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Ben Musa R, Cornelius-Green J, Zhang H, Li DP, Kline DD, Hasser EM, Cummings KJ. Orexin Facilitates the Peripheral Chemoreflex via Corticotropin-Releasing Hormone Neurons Projecting to the Nucleus of the Solitary Tract. J Neurosci 2024; 44:e2383232024. [PMID: 38789262 PMCID: PMC11223477 DOI: 10.1523/jneurosci.2383-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 04/14/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024] Open
Abstract
We previously showed that orexin neurons are activated by hypoxia and facilitate the peripheral chemoreflex (PCR)-mediated hypoxic ventilatory response (HVR), mostly by promoting the respiratory frequency response. Orexin neurons project to the nucleus of the solitary tract (nTS) and the paraventricular nucleus of the hypothalamus (PVN). The PVN contributes significantly to the PCR and contains nTS-projecting corticotropin-releasing hormone (CRH) neurons. We hypothesized that in male rats, orexin neurons contribute to the PCR by activating nTS-projecting CRH neurons. We used neuronal tract tracing and immunohistochemistry (IHC) to quantify the degree that hypoxia activates PVN-projecting orexin neurons. We coupled this with orexin receptor (OxR) blockade with suvorexant (Suvo, 20 mg/kg, i.p.) to assess the degree that orexin facilitates the hypoxia-induced activation of CRH neurons in the PVN, including those projecting to the nTS. In separate groups of rats, we measured the PCR following systemic orexin 1 receptor (Ox1R) blockade (SB-334867; 1 mg/kg) and specific Ox1R knockdown in PVN. OxR blockade with Suvo reduced the number of nTS and PVN neurons activated by hypoxia, including those CRH neurons projecting to nTS. Hypoxia increased the number of activated PVN-projecting orexin neurons but had no effect on the number of activated nTS-projecting orexin neurons. Global Ox1R blockade and partial Ox1R knockdown in the PVN significantly reduced the PCR. Ox1R knockdown also reduced the number of activated PVN neurons and the number of activated tyrosine hydroxylase neurons in the nTS. Our findings suggest orexin facilitates the PCR via nTS-projecting CRH neurons expressing Ox1R.
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Affiliation(s)
- Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
| | - Jennifer Cornelius-Green
- Department of Biomedical Sciences, College of Veterinary Medicine, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
| | - Hua Zhang
- Department of Medicine, Center for Precision Medicine, School of Medicine, University of Missouri, Columbia, Missouri 65212
| | - De-Pei Li
- Department of Medicine, Center for Precision Medicine, School of Medicine, University of Missouri, Columbia, Missouri 65212
| | - David D Kline
- Department of Biomedical Sciences, College of Veterinary Medicine, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
| | - Eileen M Hasser
- Department of Biomedical Sciences, College of Veterinary Medicine, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
| | - Kevin J Cummings
- Department of Biomedical Sciences, College of Veterinary Medicine, Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211
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Nigro E, D’Arco D, Moscatelli F, Pisani A, Amicone M, Riccio E, Capuano I, Argentino F, Monda M, Messina G, Daniele A, Polito R. Increased Expression of Orexin-A in Patients Affected by Polycystic Kidney Disease. Int J Mol Sci 2024; 25:6243. [PMID: 38892431 PMCID: PMC11172798 DOI: 10.3390/ijms25116243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 05/02/2024] [Accepted: 06/04/2024] [Indexed: 06/21/2024] Open
Abstract
Orexin-A is a neuropeptide product of the lateral hypothalamus that acts on two receptors, OX1R and OX2R. The orexinergic system is involved in feeding, sleep, and pressure regulation. Recently, orexin-A levels have been found to be negatively correlated with renal function. Here, we analyzed orexin-A levels as well as the incidence of SNPs in the hypocretin neuropeptide precursor (HCRT) and its receptors, HCRTR1 and HCRTR2, in 64 patients affected by autosomal dominant polycystic kidney disease (ADPKD) bearing truncating mutations in the PKD1 or PKD2 genes. Twenty-four healthy volunteers constituted the control group. Serum orexin-A was assessed by ELISA, while the SNPs were investigated through Sanger sequencing. Correlations with the main clinical features of PKD patients were assessed. PKD patients showed impaired renal function (mean eGFR 67.8 ± 34.53) and a statistically higher systolic blood pressure compared with the control group (p < 0.001). Additionally, orexin-A levels in PKD patients were statistically higher than those in healthy controls (477.07 ± 69.42 pg/mL vs. 321.49 ± 78.01 pg/mL; p < 0.001). Furthermore, orexin-A inversely correlated with blood pressure (p = 0.0085), while a direct correlation with eGFR in PKD patients was found. None of the analyzed SNPs showed any association with orexin-A levels in PKD. In conclusion, our data highlights the emerging role of orexin-A in renal physiology and its potential relevance to PKD. Further research is essential to elucidate the intricate mechanisms underlying orexin-A signaling in renal function and its therapeutic implications for PKD and associated cardiovascular complications.
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Affiliation(s)
- Ersilia Nigro
- Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, Farmaceutiche, Università della Campania “Luigi Vanvitelli”, Via Vivaldi 43, 81100 Caserta, Italy;
- CEINGE-Biotecnologie Avanzate Scarl “Franco Salvatore”, Via G. Salvatore 486, 80145 Napoli, Italy; (D.D.); (F.A.)
| | - Daniela D’Arco
- CEINGE-Biotecnologie Avanzate Scarl “Franco Salvatore”, Via G. Salvatore 486, 80145 Napoli, Italy; (D.D.); (F.A.)
| | - Fiorenzo Moscatelli
- Department of Human Sciences, Telematic University Pegaso, 80100 Naples, Italy;
| | - Antonio Pisani
- Unità di Nefrologia, Dipartimento di Sanità Pubblica, Università di Napoli “Federico II”, Via Pansini 5, 80131 Napoli, Italy; (A.P.); (M.A.); (E.R.); (I.C.)
| | - Maria Amicone
- Unità di Nefrologia, Dipartimento di Sanità Pubblica, Università di Napoli “Federico II”, Via Pansini 5, 80131 Napoli, Italy; (A.P.); (M.A.); (E.R.); (I.C.)
| | - Eleonora Riccio
- Unità di Nefrologia, Dipartimento di Sanità Pubblica, Università di Napoli “Federico II”, Via Pansini 5, 80131 Napoli, Italy; (A.P.); (M.A.); (E.R.); (I.C.)
| | - Ivana Capuano
- Unità di Nefrologia, Dipartimento di Sanità Pubblica, Università di Napoli “Federico II”, Via Pansini 5, 80131 Napoli, Italy; (A.P.); (M.A.); (E.R.); (I.C.)
| | - Francesca Argentino
- CEINGE-Biotecnologie Avanzate Scarl “Franco Salvatore”, Via G. Salvatore 486, 80145 Napoli, Italy; (D.D.); (F.A.)
| | - Marcellino Monda
- Sezione di Fisiologia Umana e Unità di Dietetica e Medicina dello Sport, Dipartimento di Medicina Sperimentale, Università degli Studi della Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.M.); (G.M.)
| | - Giovanni Messina
- Sezione di Fisiologia Umana e Unità di Dietetica e Medicina dello Sport, Dipartimento di Medicina Sperimentale, Università degli Studi della Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (M.M.); (G.M.)
| | - Aurora Daniele
- CEINGE-Biotecnologie Avanzate Scarl “Franco Salvatore”, Via G. Salvatore 486, 80145 Napoli, Italy; (D.D.); (F.A.)
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi “Federico II”, Via Pansini 5, 80131 Napoli, Italy
| | - Rita Polito
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy;
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Cavalu S, Saber S, Hamad RS, Abdel-Reheim MA, Elmorsy EA, Youssef ME. Orexins in apoptosis: a dual regulatory role. Front Cell Neurosci 2024; 18:1336145. [PMID: 38699177 PMCID: PMC11064656 DOI: 10.3389/fncel.2024.1336145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 04/03/2024] [Indexed: 05/05/2024] Open
Abstract
The orexins, also referred to as hypocretins, are neuropeptides that originate from the lateral hypothalamus (LH) region of the brain. They are composed of two small peptides, orexin-A, and orexin-B, which are broadly distributed throughout the central and peripheral nervous systems. Orexins are recognized to regulate diverse functions, involving energy homeostasis, the sleep-wake cycle, stress responses, and reward-seeking behaviors. Additionally, it is suggested that orexin-A deficiency is linked to sleepiness and narcolepsy. The orexins bind to their respective receptors, the orexin receptor type 1 (OX1R) and type 2 (OX2R), and activate different signaling pathways, which results in the mediation of various physiological functions. Orexin receptors are widely expressed in different parts of the body, including the skin, muscles, lungs, and bone marrow. The expression levels of orexins and their receptors play a crucial role in apoptosis, which makes them a potential target for clinical treatment of various disorders. This article delves into the significance of orexins and orexin receptors in the process of apoptosis, highlighting their expression levels and their potential contributions to different diseases. The article offers an overview of the existing understanding of the orexin/receptor system and how it influences the regulation of apoptosis.
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Affiliation(s)
- Simona Cavalu
- Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
| | - Sameh Saber
- Department of Pharmacology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
| | - Rabab S. Hamad
- Biological Sciences Department, College of Science, King Faisal University, Al Ahsa, Saudi Arabia
- Central Laboratory, Theodor Bilharz Research Institute, Giza, Egypt
| | - Mustafa Ahmed Abdel-Reheim
- Department of Pharmaceutical Sciences, College of Pharmacy, Shaqra University, Shaqra, Saudi Arabia
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Beni-Suef University, Beni Suef, Egypt
| | - Elsayed A. Elmorsy
- Department of Pharmacology and Therapeutics, College of Medicine, Qassim University, Buraidah, Saudi Arabia
- Department of Clinical Pharmacology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Mahmoud E. Youssef
- Department of Pharmacology, Faculty of Pharmacy, Delta University for Science and Technology, Gamasa, Egypt
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Narai E, Yoshimura Y, Honaga T, Mizoguchi H, Yamanaka A, Hiyama TY, Watanabe T, Koba S. Orexinergic neurons contribute to autonomic cardiovascular regulation for locomotor exercise. J Physiol 2024. [PMID: 38380995 DOI: 10.1113/jp285791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/26/2024] [Indexed: 02/22/2024] Open
Abstract
While the hypothalamic orexinergic nervous system is established as having a pivotal role in the long-term regulation of various organismic functions, including wakefulness, metabolism and hypertensive states, whether this system contributes to the rapid autonomic cardiovascular regulation during physical activity remains elusive. This study aimed to elucidate the role of the orexinergic nervous system in transmitting volitional motor signals, i.e. central command, to drive somatomotor and sympathetic cardiovascular responses. We first found that this system is activated by voluntary locomotor exercise as evidenced by an increased expression of Fos, a marker of neural activation, in the orexinergic neurons of Sprague-Dawley rats engaged in spontaneous wheel running. Next, using transgenic Orexin-Cre rats for optogenetic manipulation of orexinergic neurons, we found that optogenetic excitation of orexinergic neurons caused sympathoexcitation on a subsecond timescale under anaesthesia. In freely moving conscious rats, this excitatory stimulation rapidly elicited exploration-like behaviours, predominantly locomotor activity, along with pressor and tachycardiac responses. Meanwhile, optogenetic inhibition of orexinergic neurons during spontaneous wheel running immediately suppressed locomotor activities and blood pressure elevation without affecting basal cardiovascular homeostasis. Taken together, these findings demonstrate the essential role of the orexinergic nervous system in the central circuitry that transmits central command signals for locomotor exercise. This study not only offers insights into the brain circuit mechanisms precisely regulating autonomic cardiovascular systems during voluntary exercise but also likely contributes to our understanding of brain mechanisms underlying abnormal cardiovascular adjustments to exercise in pathological conditions, such as hypertension. KEY POINTS: The hypothalamic orexinergic nervous system plays various roles in the long-term regulation of autonomic and endocrine functions, as well as motivated behaviours. We present a novel, rapid role of the orexinergic nervous system, revealing its significance as a crucial substrate in the brain circuit mechanisms that coordinate somatomotor and autonomic cardiovascular controls for locomotor exercise. Our data demonstrate that orexinergic neurons relay volitional motor signals, playing a necessary and sufficient role in the autonomic cardiovascular regulation required for locomotor exercise in rats. The findings contribute to our understanding of how the brain precisely regulates autonomic cardiovascular systems during voluntary exercise, providing insights into the central neural mechanisms that enhance physical performance moment-by-moment during exercise.
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Affiliation(s)
- Emi Narai
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Yuki Yoshimura
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Takaho Honaga
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Hiroyuki Mizoguchi
- Department of Neuropsychopharmacology and Hospital Pharmacy, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Akihiro Yamanaka
- Chinese Institute for Brain Research, Beijing (CIBR), Beijing, China
| | - Takeshi Y Hiyama
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Tatsuo Watanabe
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
| | - Satoshi Koba
- Division of Integrative Physiology, Tottori University Faculty of Medicine, Yonago, Japan
- Division of Veterinary Physiology, Tottori University Faculty of Agriculture, Tottori, Japan
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Jászberényi M, Thurzó B, Bagosi Z, Vécsei L, Tanaka M. The Orexin/Hypocretin System, the Peptidergic Regulator of Vigilance, Orchestrates Adaptation to Stress. Biomedicines 2024; 12:448. [PMID: 38398050 PMCID: PMC10886661 DOI: 10.3390/biomedicines12020448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 02/10/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
The orexin/hypocretin neuropeptide family has emerged as a focal point of neuroscientific research following the discovery that this family plays a crucial role in a variety of physiological and behavioral processes. These neuropeptides serve as powerful neuromodulators, intricately shaping autonomic, endocrine, and behavioral responses across species. Notably, they serve as master regulators of vigilance and stress responses; however, their roles in food intake, metabolism, and thermoregulation appear complementary and warrant further investigation. This narrative review provides a journey through the evolution of our understanding of the orexin system, from its initial discovery to the promising progress made in developing orexin derivatives. It goes beyond conventional boundaries, striving to synthesize the multifaceted activities of orexins. Special emphasis is placed on domains such as stress response, fear, anxiety, and learning, in which the authors have contributed to the literature with original publications. This paper also overviews the advancement of orexin pharmacology, which has already yielded some promising successes, particularly in the treatment of sleep disorders.
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Affiliation(s)
- Miklós Jászberényi
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
| | - Balázs Thurzó
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
- Emergency Patient Care Unit, Albert Szent-Györgyi Health Centre, University of Szeged, H-6725 Szeged, Hungary
| | - Zsolt Bagosi
- Department of Pathophysiology, University of Szeged, H-6701 Szeged, Hungary; (M.J.); (B.T.); (Z.B.)
| | - László Vécsei
- Department of Neurology, Albert Szent-Györgyi Medical School, University of Szeged, H-6725 Szeged, Hungary;
- HUN-REN-SZTE Neuroscience Research Group, Hungarian Research Network, University of Szeged (HUN-REN-SZTE), Danube Neuroscience Research Laboratory, Tisza Lajos krt. 113, H-6725 Szeged, Hungary
| | - Masaru Tanaka
- HUN-REN-SZTE Neuroscience Research Group, Hungarian Research Network, University of Szeged (HUN-REN-SZTE), Danube Neuroscience Research Laboratory, Tisza Lajos krt. 113, H-6725 Szeged, Hungary
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Kim KT, Lee SU, Kim JB, Choi JY, Kim BJ, Kim JS. Augmented ocular vestibular-evoked myogenic potentials in postural orthostatic tachycardia syndrome. Clin Auton Res 2023; 33:479-489. [PMID: 37115468 DOI: 10.1007/s10286-023-00943-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 04/08/2023] [Indexed: 04/29/2023]
Abstract
PURPOSE To delineate the association between otolith function and changes in mean orthostatic blood pressure (BP) and heart rate (HR) in patients with postural orthostatic tachycardia syndrome (POTS). METHODS Forty-nine patients with POTS were prospectively recruited. We analyzed the results of ocular vestibular-evoked myogenic potentials (oVEMPs) and cervical vestibular-evoked myogenic potentials (cVEMPs), as well as head-up tilt table tests using a Finometer. The oVEMP and cVEMP responses were obtained using tapping stimuli and 110 dB tone-burst sounds, respectively. We measured maximal changes in 5-s averaged systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) within 15 s and during 10 min after tilting. We compared the results with those of 20 age- and sex-matched healthy participants. RESULTS The n1-p1 amplitude of oVEMPs was larger in patients with POTS than in healthy participants (p = 0.001), whereas the n1 latency (p = 0.280) and interaural difference (p = 0.199) did not differ between the two. The n1-p1 amplitude was a positive predictor for POTS (odds ratio 1.07, 95% confidence interval 1.01-1.13, p = 0.025). Body weight (p = 0.007) and n1-p1 amplitude of oVEMP (p = 0.019) were positive predictors for ΔSBP15s in POTS, whereas aging was a negative predictor (p = 0.005). These findings were not observed in healthy participants. CONCLUSIONS Augmented utricular inputs may be associated with a relative predominance of sympathetic over vagal control of BP and HR, especially for an early response during orthostasis in patients with POTS. Overt sympathoexcitation due to exaggerated utricular input and lack of readaptation may be associated with the pathomechanism of POTS.
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Affiliation(s)
- Keun-Tae Kim
- Department of Neurology, Korea University Medical Center, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea
| | - Sun-Uk Lee
- Department of Neurology, Korea University Medical Center, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea.
| | - Jung-Bin Kim
- Department of Neurology, Korea University Medical Center, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea
| | - Jeong-Yoon Choi
- Department of Neurology, Seoul National University College of Medicine, Seoul, South Korea
- Dizziness Center, Clinical Neuroscience Center, Seoul National University Bundang Hospital, Seongnam, South Korea
| | - Byung-Jo Kim
- Department of Neurology, Korea University Medical Center, 73 Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea
- BK21 FOUR Program in Learning Health Systems, Korea University, Seoul, South Korea
| | - Ji-Soo Kim
- Department of Neurology, Seoul National University College of Medicine, Seoul, South Korea
- Dizziness Center, Clinical Neuroscience Center, Seoul National University Bundang Hospital, Seongnam, South Korea
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Beckenstrom AC, Coloma PM, Dawson GR, Finlayson AK, Malik A, Post A, Steiner MA, Potenza MN. Use of experimental medicine approaches for the development of novel psychiatric treatments based on orexin receptor modulation. Neurosci Biobehav Rev 2023; 147:105107. [PMID: 36828161 PMCID: PMC10165155 DOI: 10.1016/j.neubiorev.2023.105107] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 02/08/2023] [Accepted: 02/18/2023] [Indexed: 02/25/2023]
Abstract
Despite progress in understanding the pathological mechanisms underlying psychiatric disorders, translation from animal models into clinical use remains a significant bottleneck. Preclinical studies have implicated the orexin neuropeptide system as a potential target for psychiatric disorders through its role in regulating emotional, cognitive, and behavioral processes. Clinical studies are investigating orexin modulation in addiction and mood disorders. Here we review performance-outcome measures (POMs) arising from experimental medicine research methods which may show promise as markers of efficacy of orexin receptor modulators in humans. POMs provide objective measures of brain function, complementing patient-reported or clinician-observed symptom evaluation, and aid the translation from preclinical to clinical research. Significant challenges include the development, validation, and operationalization of these measures. We suggest that collaborative networks comprising clinical practitioners, academics, individuals working in the pharmaceutical industry, drug regulators, patients, patient advocacy groups, and other relevant stakeholders may provide infrastructure to facilitate validation of experimental medicine approaches in translational research and in the implementation of these approaches in real-world clinical practice.
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Affiliation(s)
- Amy C Beckenstrom
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK.
| | - Preciosa M Coloma
- Idorsia Pharmaceuticals Ltd, Hegenheimermattweg 91, Allschwil 4123, Switzerland
| | - Gerard R Dawson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Ailidh K Finlayson
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK; Department of Psychology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Asad Malik
- P1vital Ltd, Manor House, Howbery Business Park, Wallingford OX10 8BA, UK
| | - Anke Post
- Corlieve Therapeutics, Swiss Innovation Park, Hegenheimermattweg 167A, 4123 Allschwil, Switzerland
| | | | - Marc N Potenza
- Departments of Psychiatry and Neuroscience and the Child Study Center, Yale School of Medicine, 1 Church Street, Room 726, New Haven, CT 06510, USA; Connecticut Mental Health Center, 34 Park Street, New Haven, CT 06519, USA; Connecticut Council on Problem Gambling, Wethersfield, CT, USA; The Wu Tsai Institute, Yale University, 100 College St, New Haven, CT 06510, USA
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Vraka K, Mytilinaios D, Katsenos AP, Serbis A, Baloyiannis S, Bellos S, Simos YV, Tzavellas NP, Konitsiotis S, Vezyraki P, Peschos D, Tsamis KI. Cellular Localization of Orexin 1 Receptor in Human Hypothalamus and Morphological Analysis of Neurons Expressing the Receptor. Biomolecules 2023; 13:biom13040592. [PMID: 37189339 DOI: 10.3390/biom13040592] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 03/21/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
The orexin system is related to food behavior, energy balance, wakefulness and the reward system. It consists of the neuropeptides orexin A and B, and their receptors, orexin 1 receptor (OX1R) and orexin 2 receptor (OX2R). OX1R has selective affinity for orexin A, and is implicated in multiple functions, such as reward, emotions, and autonomic regulation. This study provides information about the OX1R distribution in human hypothalamus. The human hypothalamus, despite its small size, demonstrates a remarkable complexity in terms of cell populations and cellular morphology. Numerous studies have focused on various neurotransmitters and neuropeptides in the hypothalamus, both in animals and humans, however, there is limited experimental data on the morphological characteristics of neurons. The immunohistochemical analysis of the human hypothalamus revealed that OX1R is mainly found in the lateral hypothalamic area, the lateral preoptic nucleus, the supraoptic nucleus, the dorsomedial nucleus, the ventromedial nucleus, and the paraventricular nucleus. The rest of the hypothalamic nuclei do not express the receptor, except for a very low number of neurons in the mammillary bodies. After identifying the nuclei and neuronal groups that were immunopositive for OX1R, a morphological and morphometric analysis of those neurons was conducted using the Golgi method. The analysis revealed that the neurons in the lateral hypothalamic area were uniform in terms of their morphological characteristics, often forming small groups of three to four neurons. A high proportion of neurons in this area (over 80%) expressed the OX1R, with particularly high expression in the lateral tuberal nucleus (over 95% of neurons). These results were analyzed, and shown to represent, at the cellular level, the distribution of OX1R, and we discuss the regulatory role of orexin A in the intra-hypothalamic areas, such as its special role in the plasticity of neurons, as well as in neuronal networks of the human hypothalamus.
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Knez R, Niksic M, Omerovic E. Orexin/hypocretin system dysfunction in patients with Takotsubo syndrome: A novel pathophysiological explanation. Front Cardiovasc Med 2022; 9:1016369. [PMID: 36407467 PMCID: PMC9670121 DOI: 10.3389/fcvm.2022.1016369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 10/05/2022] [Indexed: 09/19/2023] Open
Abstract
Takotsubo syndrome (TTS) is an acute heart failure syndrome. Emotional or physical stressors are believed to precipitate TTS, while the pathophysiological mechanism is not yet completely understood. During the coronavirus disease (COVID-19) pandemic, an increased incidence of TTS has been reported in some countries; however, the precise pathophysiological mechanism for developing TTS with acute COVID-19 infection is unknown. Nevertheless, observing the symptoms of COVID-19 might lead to new perspectives in understanding TTS pathophysiology, as some of the symptoms of the COVID-19 infection could be assessed in the context of an orexin/hypocretin-system dysfunction. Orexin/hypocretin is a cardiorespiratory neuromodulator that acts on two orexin receptors widely distributed in the brain and peripheral tissues. In COVID-19 patients, autoantibodies against one of these orexin receptors have been reported. Orexin-system dysfunction affects a variety of systems in an organism. Here, we review the influence of orexin-system dysfunction on the cardiovascular system to propose its connection with TTS. We propose that orexin-system dysfunction is a potential novel explanation for the pathophysiology of TTS due to direct or indirect dynamics of orexin signaling, which could influence cardiac contractility. This is in line with the conceptualization of TTS as a cardiovascular syndrome rather than merely a cardiac abnormality or cardiomyopathy. To the best of our knowledge, this is the first publication to present a plausible connection between TTS and orexin-system dysfunction. We hope that this novel hypothesis will inspire comprehensive studies regarding orexin's role in TTS pathophysiology. Furthermore, confirmation of this plausible pathophysiological mechanism could contribute to the development of orexin-based therapeutics in the treatment and prevention of TTS.
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Affiliation(s)
- Rajna Knez
- Gillberg Neuropsychiatry Centre, Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Research and Development, Department of Women's and Child Health, Skaraborg Hospital, Skövde, Sweden
- Institution for Health, School of Health Sciences, University of Skövde, Skövde, Sweden
| | - Milan Niksic
- Department of Cardiology, Skaraborg Hospital, Skövde, Sweden
| | - Elmir Omerovic
- Department of Molecular and Clinical Medicine/Cardiology, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
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Li MT, Robinson CL, Ruan QZ, Surapaneni S, Southerland W. The Influence of Sleep Disturbance on Chronic Pain. Curr Pain Headache Rep 2022; 26:795-804. [PMID: 36190680 DOI: 10.1007/s11916-022-01074-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/27/2022] [Indexed: 12/01/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to present an overview of common sleep disturbance pathologies and their impact on chronic pain, while examining various factors that are implicit in the relationship between sleep disturbance and chronic pain, including neurobiochemistry, anatomy, and systemic mediators, and reviewing recent and landmark literature. RECENT FINDINGS Earlier literature reviews and studies have introduced the bidirectional relationship between sleep disturbance and chronic pain; that is, impaired sleep may worsen chronic pain, and chronic pain causes sleep disturbance. However, more recent reviews and studies seem to show a more associative, rather than causative relationship. There have been recent studies that attempt to determine mechanisms that link sleep disturbance and chronic pain; the results of these studies were more varied, ultimately concluding that there may be a separate, yet-to-be discovered mechanism that shows the causative relationship between sleep disturbance and pain. There are several neurotransmitters that are involved in the mediation of chronic pain and sleep disturbance as separate entities, and some studies have shown that there may be mechanisms that govern both chronic pain and sleep disturbance as a single unit. Other neuroendocrine substances also serve to mediate chronic pain and sleep disturbance. All these substances are found to be associated with various sleep disorders and are also associated with chronic pain symptoms as well. Inflammation plays a role in chronic pain and sleep disturbance, with an increase in inflammatory substances and mediators associated with an increase or worsening in chronic pain symptoms and sleep disorders. The HPA axis plays a role in chronic pain and sleep disorders, influencing pain and sleep pathways through stress response, inflammation, and maintenance of homeostasis. There are several variables that influence both chronic pain and sleep disturbance, and more research into these variables may further our understanding into the complex pathways governing the influence of sleep disturbance on pain, and ultimately to improve treatment for this issue.
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Affiliation(s)
- Michael T Li
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Christopher Louis Robinson
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Qing Zhao Ruan
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Sindhuja Surapaneni
- Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Warren Southerland
- Department of Anesthesia, The Hospital of the University of Pennsylvania, Philadelphia, PA, USA
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11
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Spinieli RL, Ben Musa R, Cornelius-Green J, Hasser EM, Cummings KJ. Orexin facilitates the ventilatory and behavioral responses of rats to hypoxia. Am J Physiol Regul Integr Comp Physiol 2022; 322:R581-R596. [PMID: 35380477 PMCID: PMC9109809 DOI: 10.1152/ajpregu.00334.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 03/22/2022] [Accepted: 03/30/2022] [Indexed: 02/03/2023]
Abstract
Orexin neurons are sensitive to CO2 and contribute to cardiorespiratory homeostasis as well as sensorimotor control. Whether orexin facilitates respiratory and behavioral responses to acute hypoxia is unclear. We hypothesized that orexin neurons are activated by acute hypoxia and that orexin facilitates the hypoxic ventilatory response (HVR), as well as the arterial blood pressure (ABP) and behavioral (movement) responses to acute hypoxia. We further hypothesized that orexin has greater effects in the active phase of the rat circadian cycle, when orexin neurons have high activity. Using whole body plethysmography with EEG, EMG, and the dual-orexin receptor (OxR) antagonist suvorexant (20 mg/kg ip), we determined the effect of OxR blockade on the respiratory, ABP, and behavioral responses of adult rats to acute, graded hypoxia ([Formula: see text]= 0.15, 0.13, 0.11, and 0.09) and hyperoxic hypercapnia ([Formula: see text]= 0.05; [Formula: see text]= 0.95). OxR blockade had no effect on eupnea. OxR blockade significantly reduced the HVR in both inactive and active phases, with a stronger effect in the active phase. OxR blockade reduced the behavioral response to acute hypoxia in the active phase. The central component of the ventilatory and the ABP responses to hypercapnia were reduced by OxR blockade solely in the inactive phase. In the inactive phase, hypoxia activated ∼10% of orexin neurons in the perifornical hypothalamus. These data suggest that orexin neurons participate in the peripheral chemoreflex to facilitate the ventilatory and behavioral responses to acute hypoxia in rats, particularly in the active phase. Orexin also facilitates central chemoreflex responses to CO2 in the inactive phase.
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Affiliation(s)
- Richard L Spinieli
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Jennifer Cornelius-Green
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Eileen M Hasser
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Kevin J Cummings
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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12
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Parekh RU, White A, Leffler KE, Biancardi VC, Eells JB, Abdel-Rahman AA, Sriramula S. Hypothalamic kinin B1 receptor mediates orexin system hyperactivity in neurogenic hypertension. Sci Rep 2021; 11:21050. [PMID: 34702886 PMCID: PMC8548389 DOI: 10.1038/s41598-021-00522-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/13/2021] [Indexed: 12/05/2022] Open
Abstract
Brain orexin system hyperactivity contributes to neurogenic hypertension. We previously reported upregulated neuronal kinin B1 receptor (B1R) expression in hypertension. However, the role of central B1R activation on the orexin system in neurogenic hypertension has not been examined. We hypothesized that kinin B1R contributes to hypertension via upregulation of brain orexin-arginine vasopressin signaling. We utilized deoxycorticosterone acetate (DOCA)-salt hypertension model in wild-type (WT) and B1R knockout (B1RKO) mice. In WT mice, DOCA-salt-treatment increased gene and protein expression of orexin A, orexin receptor 1, and orexin receptor 2 in the hypothalamic paraventricular nucleus and these effects were attenuated in B1RKO mice. Furthermore, DOCA-salt- treatment increased plasma arginine vasopressin levels in WT mice, but not in B1RKO mice. Cultured primary hypothalamic neurons expressed orexin A and orexin receptor 1. B1R specific agonist (LDABK) stimulation of primary neurons increased B1R protein expression, which was abrogated by B1R selective antagonist R715 but not by the dual orexin receptor antagonist, ACT 462206, suggesting that B1R is upstream of the orexin system. These data provide novel evidence that B1R blockade blunts orexin hyperactivity and constitutes a potential therapeutic target for the treatment of salt-sensitive hypertension.
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Affiliation(s)
- Rohan Umesh Parekh
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
| | - Acacia White
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
| | - Korin E Leffler
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
| | - Vinicia C Biancardi
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA
- Center for Neuroscience Initiative, Auburn University, Auburn, AL, USA
| | - Jeffrey B Eells
- 4Department of Anatomy and Cell Biology, Brody School of Medicine at East, Carolina University, Greenville, NC, 27834, USA
| | - Abdel A Abdel-Rahman
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA
| | - Srinivas Sriramula
- Department of Pharmacology and Toxicology, Brody School of Medicine at East Carolina University, 600 Moye Blvd, Greenville, NC, 27834, USA.
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13
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Spinieli RL, Ben Musa R, Kielhofner J, Cornelius-Green J, Cummings KJ. Orexin contributes to eupnea within a critical period of postnatal development. Am J Physiol Regul Integr Comp Physiol 2021; 321:R558-R571. [PMID: 34405704 PMCID: PMC8560369 DOI: 10.1152/ajpregu.00156.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/10/2021] [Accepted: 08/10/2021] [Indexed: 02/03/2023]
Abstract
Orexin neurons are active in wakefulness and mostly silent in sleep. In adult rats and humans, orexin facilitates the hypercapnic ventilatory response but has little effect on resting ventilation. The influence of orexin on breathing in the early postnatal period, and across states of vigilance, have not been investigated. This is relevant as the orexin system may be impaired in Sudden Infant Death Syndrome (SIDS) cases. We addressed three hypotheses: 1) orexin provides a drive to breathe in infancy; 2) the effect of orexin depends on stage of postnatal development; and 3) orexin has a greater influence on breathing in wakefulness compared with sleep. Whole body plethysmography was used to monitor breathing of infant rats at three ages: postnatal days (P) 7-8, 12-14, and 17-19. Respiratory variables were analyzed in wakefulness (W), quiet sleep (QS), and active sleep (AS), following suvorexant (5 mg/kg ip), a dual orexin receptor antagonist, or vehicle (DMSO). Effects of suvorexant on ventilatory responses to graded hypercapnia ([Formula: see text] = 0.02, 0.04, 0.06), hypoxia ([Formula: see text] = 0.10), and hyperoxia ([Formula: see text] = 1.0) at P12-14 were also tested. At P12-14, but not at other ages, suvorexant significantly reduced respiratory frequency in all states, reduced the ventilatory equivalent in QW and QS, and increased [Formula: see text] to ∼5 mmHg. Suvorexant had no effect on ventilatory responses to graded hypercapnia or hypoxia. Hyperoxia eliminated the effects of suvorexant on respiratory frequency at P12-14. Our data suggest that orexin preserves eupneic frequency and ventilation in rats, specifically at ∼2 wk of age, perhaps by facilitating tonic peripheral chemoreflex activity.
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Affiliation(s)
- Richard L Spinieli
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - Ruwaida Ben Musa
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | - Jane Kielhofner
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri
| | | | - Kevin J Cummings
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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14
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Fan Y, Jiang E, Gao H, Bigalke J, Chen B, Yu C, Chen Q, Shan Z. Activation of Orexin System Stimulates CaMKII Expression. Front Physiol 2021; 12:698185. [PMID: 34276418 PMCID: PMC8282234 DOI: 10.3389/fphys.2021.698185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/08/2021] [Indexed: 11/18/2022] Open
Abstract
Hyperactivity of the orexin system within the paraventricular nucleus (PVN) has been shown to contribute to increased sympathetic nerve activity (SNA) and blood pressure (BP) in rodent animals. However, the underlying molecular mechanisms remain unclear. Here, we test the hypothesis that orexin system activation stimulates calcium/calmodulin-dependent kinase II (CaMKII) expression and activation, and stimulation of CaMKII expressing PVN neurons increases SNA and BP. Real-time PCR and/or western blot were carried out to test the effect of orexin-A administration on CaMKII expression in the PVN of normal Sprague Dawley (SD) rats and orexin receptor 1 (OX1R) expressing PC12 cells. Immunostaining was performed to assess OX1R cellular localization in the PVN of SD rats as well as orexin-A treatment on CaMKII activation in cultured hypothalamic neurons. In vivo sympathetic nerve recordings were employed to test the impact of optogenetic stimulation of CaMKII-expressing PVN neurons on the renal SNA (RSNA) and BP. The results showed that intracerebroventricular injection of orexin-A into the SD rat increases mRNA expression of CaMKII subunits in the PVN. In addition, Orexin-A treatment increases CaMKII expression and its phosphorylation in OX1R-expressing PC12 cells. Furthermore, Orexin-A treatment increases CaMKII activation in cultured hypothalamic neurons from neonatal SD rats. Finally, optogenetic excitation of PVN CaMKII-expressing neurons results in robust increases in RSNA and BP in SD rats. Our results suggest that increased orexin system activity activates CaMKII expression in cardiovascular relevant regions, and this may be relevant to the downstream cardiovascular effects of CaMKII.
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Affiliation(s)
- Yuanyuan Fan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,School of Life Sciences, Henan University, Kaifeng, China
| | - Enshe Jiang
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Institute of Nursing and Health, Henan University, Kaifeng, China
| | - Huanjia Gao
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,The Second Clinical College, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jeremy Bigalke
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
| | - Bojun Chen
- Department of Emergency, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Chunxiu Yu
- Health Research Institute, Michigan Technological University, Houghton, MI, United States.,Department of Biological Sciences, Michigan Technological University, Houghton, MI, United States
| | - Qinghui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
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15
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Izumida T, Nakamura Y, Sato Y, Ishikawa S. The Association between Sleeping Pill Use and Metabolic Syndrome in an Apparently Healthy Population in Japan: JMS-II Cohort Study. J Epidemiol 2020; 32:145-150. [PMID: 33162423 PMCID: PMC8824657 DOI: 10.2188/jea.je20200361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background Sleeping pills are widely used for sleep disorders and insomnia. This population-based study aimed to evaluate the association between the use of sleeping pills and metabolic syndrome (MetS) and metabolic components in an apparently healthy Japanese cohort. Methods We examined baseline cross-sectional data from the JMS-II Cohort Study. The criteria for MetS and its components were based on The National Cholesterol Education Program Adult Treatment Panel III. Sleep habits including the sleep duration of the subjects and the frequency of sleeping pill use were obtained using The Pittsburgh Sleep Quality Index questionnaire. For different sleep durations, the association between sleeping pill use and MetS was assessed. Odds ratios (ORs) and their 95% confidence intervals (CIs) were estimated using multiple logistic regression models to quantify this association. Results Our study included 6,153 individuals (mean age, 63.8 [standard deviation 11.2] years), and 3,348 (54.4%) among them were women. The association between sleep duration and MetS was an inverted J-shaped curve among sleeping pill users and a J-shaped curve among non-users. After adjustment for various confounders, less than 6 h of sleep among sleeping pill users was associated with increased rates of MetS (<6 h, OR 3.08; 95% CI, 1.29–7.34]). The frequency of sleeping pill use in individuals with short sleep duration showed a positive association with the prevalence of MetS and its components. Conclusions Sleeping pill users with a short sleep duration had a 3-fold higher chance of having MetS than non-users with a short sleep duration.
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Affiliation(s)
- Toshihide Izumida
- Division of Community Medicine, Kanawaza Medical University Himi Municipal Hospital
| | - Yosikazu Nakamura
- Division of Public Health, Center for Community Medicine, Jichi Medical University
| | | | - Shizukiyo Ishikawa
- Division of Public Health, Center for Community Medicine, Jichi Medical University
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16
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Williams DL, Coiduras II, Parise EM, Maske CB. Hindbrain orexin 1 receptors blunt intake suppression by gastrointestinal nutrients and cholecystokinin in male rats. Peptides 2020; 133:170351. [PMID: 32579900 PMCID: PMC7556705 DOI: 10.1016/j.peptides.2020.170351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/19/2020] [Accepted: 06/19/2020] [Indexed: 01/06/2023]
Abstract
Hypothalamic orexin neurons project to many brain areas, including hindbrain structures such as the nucleus of the solitary tract (NTS) and area postrema (AP), where orexin 1 receptors (OX1Rs) are expressed. Hindbrain administration of orexin-A increases feeding and meal size, and blockade of hindbrain OX1Rs with the selective antagonist SB334867 has the opposite effect. Here we asked whether hindbrain OX1R stimulation or blockade alter rats' sensitivity to gastrointestinal satiety signals. Rats received 4th intracerebroventricular (icv) injections of vehicle or orexin-A, at a dose with no effect on its own, prior to an intragastric (IG) infusion of saline or a satiating volume of Ensure. IG Ensure suppressed subsequent chow intake, but orexin-A pretreatment significantly attenuated this IG nutrient-induced satiety at 2 h into the dark phase. In a second experiment, rats received NTS injections of vehicle or orexin-A before intraperitoneal (IP) injection of vehicle or the satiation hormone cholecystokinin (CCK). NTS orexin-A pretreatment completely blocked the intake-suppressive effect of CCK on dark-phase chow intake. Finally, we investigated the role of endogenous hindbrain OX1R activation by pretreating rats with 4th-icv injection of vehicle or SB334867 followed by IG infusion of saline or Ensure just before a chocolate Ensure licking test session. IG nutrient infusion suppressed Ensure intake, and blockade of hindbrain OX1Rs significantly prolonged that intake-suppressive effect. We conclude that hindbrain OX1Rs are a mechanism though which hypothalamic orexin neurons can reduce animals' sensitivity to gastrointestinal nutrient load, allowing them to consume more food.
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Affiliation(s)
- Diana L Williams
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306-4301 USA.
| | - Isabel I Coiduras
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306-4301 USA
| | - Eric M Parise
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306-4301 USA
| | - Calyn B Maske
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, FL, 32306-4301 USA
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17
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Kowalewski S, Czarzasta K, Puchalska L, Szczepańska-Sadowska E, Wsol A, Cudnoch-Jędrzejewska A. Interaction of Orexin A and Vasopressin in the Brain Plays a Role in Blood Pressure Regulation in WKY and SHR Rats. Med Sci Monit 2020; 26:e926825. [PMID: 33048914 PMCID: PMC7568440 DOI: 10.12659/msm.926825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Background Orexin A (OXA) and vasopressin (AVP) exert a central hypertensive effect due to an increase in sympathetic nerve activity. To date, little is known about the interaction of these 2 neuropeptides in the central regulation of blood pressure. The present study compared the consequences of infusion into the left cerebral ventricle (ICV) of OXA on mean arterial blood pressure (MABP) in normotensive (WKY) and spontaneously hypertensive (SHR) rats, and explored whether the central pressor action of OXA in these 2 strains depends on activation of brain AVP V1a receptors (V1aR). Material/Methods Ten groups of experiments were performed on 12-week-old WKY and SHR rats implanted with ICV cannulas for infusion of OXA (3 nmol) and V1aR antagonist (V1aRANT, 500 ng), administered separately and together. Levels of V1aR and OXR in the medulla oblongata of WKY and SHR rats were compared in separate series. Results We found that: 1) OXA significantly increased MABP only in WKY rats, 2) V1aRANT prevented an increase in MABP induced by OXA in WKY rats and decreased MABP in SHR rats, 3) OXA abolished the hypotensive action of V1aRANT in SHR rats, and 4) SHR rats had significantly higher levels of OX1R and V1aR proteins and OX1R mRNA in the brain medulla. Conclusions The present study shows that OXA and AVP can interact in the brain to affect blood pressure regulation, and that this interaction differs in normotension and hypertension.
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Affiliation(s)
- Stanisław Kowalewski
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Katarzyna Czarzasta
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Liana Puchalska
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Ewa Szczepańska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Agnieszka Wsol
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Agnieszka Cudnoch-Jędrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of the Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
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18
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Cui SY, Huang YL, Cui XY, Zhao HL, Hu X, Liu YT, Qin Y, Kurban N, Zhang YH. A common neuronal mechanism of hypertension and sleep disturbances in spontaneously hypertensive rats: Role of orexinergic neurons. Prog Neuropsychopharmacol Biol Psychiatry 2020; 100:109902. [PMID: 32109507 DOI: 10.1016/j.pnpbp.2020.109902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/31/2020] [Accepted: 02/24/2020] [Indexed: 10/24/2022]
Abstract
Epidemiologic studies have shown that sleep disorders are associated with the development of hypertension. The present study investigated dynamic changes in sleep patterns during the development of hypertension across the lifespan in spontaneously hypertensive rats (SHRs) and the neural mechanism that underlies these comorbidities, with a focus on the orexinergic system. Blood pressure in rats was measured using a noninvasive blood pressure tail cuff. Sleep was monitored by electroencephalographic and electromyographic recordings. Immunohistochemistry was used to detect the density and activity of orexinergic neurons in the perifornical nucleus. Hcrt2-SAP (400 or 800 ng) was microinjected in the lateral hypothalamus to lesion orexinergic neurons. Compared with Wistar-Kyoto rats, SHRs exhibited various patterns of sleep disturbances. In SHRs, dynamic changes in hypersomnia in the rats' active phase was not synchronized with the development of hypertension, but hyperarousal in the inactive phase and difficulties in falling asleep were observed concurrently with the development of hypertension. Furthermore, the density and activity of orexinergic neurons in the perifornical nucleus were significantly higher in SHRs than in age-matched Wistar-Kyoto rats. The reduction of orexinergic neurons in the lateral hypothalamus partially ameliorated the development of hypertension and prevented difficulties in falling asleep in SHRs. These results indicate that although the correlation between sleep disturbances and hypertension is very complex, common mechanisms may underlie these comorbidities in SHRs. Overactivity of the orexin system may be one such common mechanism.
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Affiliation(s)
- Su-Ying Cui
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Yuan-Li Huang
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Xiang-Yu Cui
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Hui-Ling Zhao
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Xiao Hu
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Yu-Tong Liu
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Yu Qin
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Nurhumar Kurban
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China
| | - Yong-He Zhang
- Department of Pharmacology, Peking University, School of Basic Medical Science, 38 Xueyuan Road, Beijing 100191, China.
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19
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Kim JS, Martin-Fardon R. Possible Role of CRF-Hcrt Interaction in the Infralimbic Cortex in the Emergence and Maintenance of Compulsive Alcohol-Seeking Behavior. Alcohol Clin Exp Res 2020; 44:354-367. [PMID: 31840823 DOI: 10.1111/acer.14264] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 11/28/2019] [Indexed: 12/19/2022]
Abstract
Alcohol use disorder (AUD) is a chronic, relapsing disorder that is characterized by the compulsive use of alcohol despite numerous health, social, and economic consequences. Initially, the use of alcohol is driven by positive reinforcement. Over time, however, alcohol use can take on a compulsive quality that is driven by the desire to avoid the negative consequences of abstinence, including negative affect and heightened stress/anxiety. This transition from positive reinforcement- to negative reinforcement-driven consumption involves the corticotropin-releasing factor (CRF) system, although mounting evidence now suggests that the CRF system interacts with other neural systems to ultimately produce behaviors that are symptomatic of compulsive alcohol use, such as the hypocretin (Hcrt) system. Hypocretins are produced exclusively in the hypothalamus, but Hcrt neurons project widely throughout the brain and reach regions that perform regulatory functions for numerous behavioral and physiological responses-including the infralimbic cortex (IL) of the medial prefrontal cortex (mPFC). Although the entire mPFC undergoes neuroadaptive changes following prolonged alcohol exposure, the IL appears to undergo more robust changes compared with other mPFC substructures. Evidence to date suggests that the IL is likely involved in EtOH-seeking behavior, but ambiguities with respect to the specific role of the IL in this regard make it difficult to draw definitive conclusions. Furthermore, the manner in which CRF interacts with Hcrt in this region as it pertains to alcohol-seeking behavior is largely unknown, although immunohistochemical and electrophysiological experiments have shown that CRF and Hcrt directly interact in the mPFC, suggesting that the interaction between CRF and Hcrt in the IL may be critically important for the development and subsequent maintenance of compulsive alcohol seeking. This review aims to consolidate recent literature regarding the role of the IL in alcohol-seeking behavior and to discuss evidence that supports a functional interaction between Hcrt and CRF in the IL.
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Affiliation(s)
- Jung S Kim
- From the, Department of Molecular Medicine, Scripps Research, La Jolla, California
| | - Rémi Martin-Fardon
- From the, Department of Molecular Medicine, Scripps Research, La Jolla, California
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Jackson KL, Head GA, Gueguen C, Stevenson ER, Lim K, Marques FZ. Mechanisms Responsible for Genetic Hypertension in Schlager BPH/2 Mice. Front Physiol 2019; 10:1311. [PMID: 31681017 PMCID: PMC6813185 DOI: 10.3389/fphys.2019.01311] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 09/30/2019] [Indexed: 01/18/2023] Open
Abstract
It has been 45 years since Gunther Schlager used a cross breeding program in mice to develop inbred strains with high, normal, and low blood pressure (BPH/2, BPN/3, and BPL/1 respectively). Thus, it is timely to gather together the studies that have characterized and explored the mechanisms associated with the hypertension to take stock of exactly what is known and what remains to be determined. Growing evidence supports the notion that the mechanism of hypertension in BPH/2 mice is predominantly neurogenic with some of the early studies showing aberrant brain noradrenaline levels in BPH/2 compared with BPN/3. Analysis of the adrenal gland using microarray suggested an association with the activity of the sympathetic nervous system. Indeed, in support of this, there is a larger depressor response to ganglion blockade, which reduced blood pressure in BPH/2 mice to the same level as BPN/3 mice. Greater renal tyrosine hydroxylase staining and greater renal noradrenaline levels in BPH/2 mice suggest sympathetic hyperinnervation of the kidney. Renal denervation markedly reduced the blood pressure in BPH/2 but not BPN/3 mice, confirming the importance of renal sympathetic nervous activity contributing to the hypertension. Further, there is an important contribution to the hypertension from miR-181a and renal renin in this strain. BPH/2 mice also display greater neuronal activity of amygdalo-hypothalamic cardiovascular regulatory regions. Lesions of the medial nucleus of the amygdala reduced the hypertension in BPH/2 mice and abolished the strain difference in the effect of ganglion blockade, suggesting a sympathetic mechanism. Further studies suggest that aberrant GABAergic inhibition may play a role since BPH/2 mice have low GABAA receptor δ, α4 and β2 subunit mRNA expression in the hypothalamus, which are predominantly involved in promoting tonic neuronal inhibition. Allopregnanolone, an allosteric modulator of GABAA receptors, which increase the expression of these subunits in the amygdala and hypothalamus, is shown to reduce the hypertension and sympathetic nervous system contribution in BPH/2 mice. Thus far, evidence suggests that BPH/2 mice have aberrant GABAergic inhibition, which drives neuronal overactivity within amygdalo-hypothalamic brain regions. This overactivity is responsible for the greater sympathetic contribution to the hypertension in BPH/2 mice, thus making this an ideal model of neurogenic hypertension.
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Affiliation(s)
- Kristy L Jackson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Geoffrey A Head
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Cindy Gueguen
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Emily R Stevenson
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
| | - Kyungjoon Lim
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Melbourne, VIC, Australia
| | - Francine Z Marques
- Neuropharmacology Laboratory, Baker Heart and Diabetes Institute, Melbourne, VIC, Australia.,Hypertension Research Laboratory, School of Biological Sciences, Monash University, Clayton, VIC, Australia
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Wang L, He T, Wan B, Wang X, Zhang L. Orexin A ameliorates HBV X protein-induced cytotoxicity and inflammatory response in human hepatocytes. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2019; 47:2003-2009. [PMID: 31106596 DOI: 10.1080/21691401.2019.1614014] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Li Wang
- Department of Hepatopancreatobiliary Surgery, He’nan Tumor Hospital, Affiliated to Zhengzhou University, Zhengzhou, China
| | - Tao He
- Department of Hepatopancreatobiliary Surgery, He’nan Tumor Hospital, Affiliated to Zhengzhou University, Zhengzhou, China
| | - Baishun Wan
- Department of Hepatopancreatobiliary Surgery, He’nan Tumor Hospital, Affiliated to Zhengzhou University, Zhengzhou, China
| | - Xiaoqian Wang
- Department of Hepatopancreatobiliary Surgery, He’nan Tumor Hospital, Affiliated to Zhengzhou University, Zhengzhou, China
| | - Ling Zhang
- Department of Hepatopancreatobiliary Surgery, He’nan Tumor Hospital, Affiliated to Zhengzhou University, Zhengzhou, China
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Kario K, Yamasaki K, Yagi K, Tsukamoto M, Yamazaki S, Okawara Y, Tomitani N, Kanegae H. Effect of suvorexant on nighttime blood pressure in hypertensive patients with insomnia: The SUPER‐1 study. J Clin Hypertens (Greenwich) 2019; 21:896-903. [DOI: 10.1111/jch.13505] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Kazuomi Kario
- Jichi Medical University School of Medicine Tochigi Japan
| | | | | | | | - Shoji Yamazaki
- Jichi Medical University School of Medicine Tochigi Japan
| | - Yukie Okawara
- Jichi Medical University School of Medicine Tochigi Japan
| | - Naoko Tomitani
- Jichi Medical University School of Medicine Tochigi Japan
| | - Hiroshi Kanegae
- Jichi Medical University School of Medicine Tochigi Japan
- Genki Plaza Medical Center for Health Care Tokyo Japan
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Takekawa D, Kushikata T, Akaishi M, Nikaido Y, Hirota K. Influence of Orexinergic System on Survival in Septic Rats. Neuropsychobiology 2018; 77:45-48. [PMID: 30326465 DOI: 10.1159/000493739] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/13/2018] [Indexed: 11/19/2022]
Abstract
BACKGROUND The orexinergic (OXergic) system contributes to the defense system. It has also been reported that the degeneration of OXergic neurons occurs during sepsis. Thus, the decline of OXergic activity may contribute to impairment of the defense system in sepsis. In this study, we determined whether: (i) lipopolysaccharide (LPS) reduces the brain orexin A (OXA) content and (ii) the OXergic system contributes to survival from sepsis in rats. METHODS With approval of our protocol by our University Animal Ethics Committee, OX neuron-ablated (OX/ataxin-3 transgenic [OX/AT3 TG]) and wild-type Sprague-Dawley rats, weighing 250-350 g, were used. LPS (10 mg/kg) was administered intraperitonally to the wild-type rats (group SD, n = 26) and OX/AT3 TG rats (group TG, n = 14). Another 7 SD rats were included as a saline control (group C). Survival analysis was then performed over a period of 3 days. All surviving rats were decapitated and the brain OXA contents (from the cerebrocortex, hippocampus, hypothalamus, and pons) were quantified using ELISA kits. RESULTS In group SD, 61.5% rats survived, while in group TG, only 21.4% survived (p < 0.05). LPS significantly reduced OXA content (pg/mg of tissue) in group SD (2.92 ± 0.38) compared to in group C (4.10 ± 1.21) in the pons (p < 0.05). OXA content in group TG was substantially lower than in group C and group SD in all brain regions. CONCLUSIONS LPS significantly reduced OXA contents in the pons which contains the locus coeruleus to regulate sympathetic activity in the defense system.
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24
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Zhang H, Liang B, Li T, Zhou Y, Shang D, Du Z. Orexin A Suppresses Oxidized LDL Induced Endothelial Cell Inflammation via
MAPK p38 and NF-κB Signaling Pathway. IUBMB Life 2018; 70:961-968. [PMID: 30207631 DOI: 10.1002/iub.1890] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/13/2018] [Accepted: 05/02/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Haiyang Zhang
- Department of Emergency; Shandong Provincial Hospital Affiliated to Shandong University; Jinan China
| | - Bin Liang
- Division of Respiration, Department of Internal Medicine; Shandong Provincial Hospital Affiliated to Shandong University; Jinan China
| | - Tao Li
- Department of Emergency; Shandong Provincial Hospital Affiliated to Shandong University; Jinan China
| | - Yi Zhou
- Department of Emergency; Shandong Provincial Hospital Affiliated to Shandong University; Jinan China
| | - Deya Shang
- Department of Emergency; Shandong Provincial Hospital Affiliated to Shandong University; Jinan China
| | - Zhongjun Du
- Department of Toxicology; Shandong Academy of Occupational Health and Occupational Medicine, Shandong Academy of Medical Sciences; Jinan China
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25
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Abreu AR, Molosh AI, Johnson PL, Shekhar A. Role of medial hypothalamic orexin system in panic, phobia and hypertension. Brain Res 2018; 1731:145942. [PMID: 30205108 DOI: 10.1016/j.brainres.2018.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 12/11/2022]
Abstract
Orexin has been implicated in a number of physiological functions, including arousal, regulation of sleep, energy metabolism, appetitive behaviors, stress, anxiety, fear, panic, and cardiovascular control. In this review, we will highlight research focused on orexin system in the medial hypothalamic regions of perifornical (PeF) and dorsomedial hypothalamus (DMH), and describe the role of this hypothalamic neuropeptide in the behavioral expression of panic and consequent fear and avoidance responses, as well as sympathetic regulation and possible development of chronic hypertension. We will also outline recent data highlighting the clinical potential of single and dual orexin receptor antagonists for neuropsychiatric conditions including panic, phobia, and cardiovascular conditions, such as in hypertension.
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Affiliation(s)
- Aline R Abreu
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrei I Molosh
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Philip L Johnson
- Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anantha Shekhar
- Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA; Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Clinical and Translational Sciences Institute, Indiana University School of Medicine, Indianapolis, IN, USA.
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26
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Kim P, During E, Miglis M. A Case of Narcolepsy Type 2 and Postural Tachycardia Syndrome Secondary to Lesions of the Thalamus and Amygdala. J Clin Sleep Med 2018; 14:479-481. [PMID: 29458703 PMCID: PMC5837851 DOI: 10.5664/jcsm.7006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/10/2017] [Accepted: 11/15/2017] [Indexed: 11/13/2022]
Abstract
ABSTRACT Although there are reports of narcolepsy type 1 caused by lesions of the central nervous system, there are far fewer reports of narcolepsy type 2 (NT2) caused by discrete brain lesions. We report a case of a patient in whom NT2 was diagnosed after a viral illness, and inflammatory lesions in the right thalamus and amygdala were found. In addition, symptoms of autonomic impairment developed and postural tachycardia syndrome was subsequently diagnosed in this patient. To our knowledge this is the first reported case of NT2 resulting from central nervous system lesions in these discrete locations, as well as the first reported case of postural tachycardia syndrome associated with narcolepsy.
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Affiliation(s)
- Paul Kim
- Department of Neurology & Neurological Sciences, Stanford University Medical Center, Palo Alto, California
| | - Emmanuel During
- Department of Neurology & Neurological Sciences, Stanford University Medical Center, Palo Alto, California
- Stanford Center for Sleep Sciences and Medicine, Department of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Palo Alto, California
| | - Mitchell Miglis
- Department of Neurology & Neurological Sciences, Stanford University Medical Center, Palo Alto, California
- Stanford Center for Sleep Sciences and Medicine, Department of Psychiatry and Behavioral Sciences, Stanford University Medical Center, Palo Alto, California
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27
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Hernandez M, Watkins J, Vu J, Hayward L. DOCA/salt hypertension alters Period1 and orexin-related gene expression in the medulla and hypothalamus of male rats: Diurnal influences. Auton Neurosci 2018; 210:34-43. [DOI: 10.1016/j.autneu.2017.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 10/18/2022]
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Huber MJ, Chen QH, Shan Z. The Orexin System and Hypertension. Cell Mol Neurobiol 2017; 38:385-391. [PMID: 28349223 DOI: 10.1007/s10571-017-0487-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 03/18/2017] [Indexed: 12/18/2022]
Abstract
In this review, we focus on the role of orexin signaling in blood pressure control and its potential link to hypertension by summarizing evidence from several experimental animal models of hypertension. Studies using the spontaneously hypertensive rat (SHR) animal model of human essential hypertension show that pharmacological blockade of orexin receptors reduces blood pressure in SHRs but not in Wistar-Kyoto rats. In addition, increased activity of the orexin system contributes to elevated blood pressure and sympathetic nerve activity (SNA) in dark-active period Schlager hypertensive (BPH/2J) mice, another genetic model of neurogenic hypertension. Similar to these two models, Sprague-Dawley rats with stress-induced hypertension display an overactive central orexin system. Furthermore, upregulation of the orexin receptor 1 increases firing of hypothalamic paraventricular nucleus neurons, augments SNA, and contributes to hypertension in the obese Zucker rat, an animal model of obesity-related hypertension. Finally, we propose a hypothesis for the implication of the orexin system in salt-sensitive hypertension. All of this evidence, coupled with the important role of elevated SNA in increasing blood pressure, strongly suggests that hyperactivity of the orexin system contributes to hypertension.
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Affiliation(s)
- Michael J Huber
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC 231, 1400 Townsend Drive, Houghton, MI, 49931, USA
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC 231, 1400 Townsend Drive, Houghton, MI, 49931, USA
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC 231, 1400 Townsend Drive, Houghton, MI, 49931, USA.
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30
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Ibrahim NE, Rabideau DJ, Gaggin HK, Belcher AM, Conrad MJ, Jarolim P, Januzzi JL. Circulating Concentrations of Orexin A Predict Left Ventricular Myocardial Remodeling. J Am Coll Cardiol 2016; 68:2238-2240. [DOI: 10.1016/j.jacc.2016.08.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Revised: 07/29/2016] [Accepted: 08/07/2016] [Indexed: 11/30/2022]
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Dergacheva O, Yamanaka A, Schwartz AR, Polotsky VY, Mendelowitz D. Direct projections from hypothalamic orexin neurons to brainstem cardiac vagal neurons. Neuroscience 2016; 339:47-53. [PMID: 27693474 DOI: 10.1016/j.neuroscience.2016.09.038] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 11/29/2022]
Abstract
Orexin neurons are known to augment the sympathetic control of cardiovascular function, however the role of orexin neurons in parasympathetic cardiac regulation remains unclear. To test the hypothesis that orexin neurons contribute to parasympathetic control we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in orexin-Cre transgenic rats and examined postsynaptic currents in cardiac vagal neurons (CVNs) in the dorsal motor nucleus of the vagus (DMV). Simultaneous photostimulation and recording in ChR2-expressing orexin neurons in the lateral hypothalamus resulted in reliable action potential firing as well as large whole-cell currents suggesting a strong expression of ChR2 and reliable optogenetic excitation. Photostimulation of ChR2-expressing fibers in the DMV elicited short-latency (ranging from 3.2ms to 8.5ms) postsynaptic currents in 16 out of 44 CVNs tested. These responses were heterogeneous and included excitatory glutamatergic (63%) and inhibitory GABAergic (37%) postsynaptic currents. The results from this study suggest different sub-population of orexin neurons may exert diverse influences on brainstem CVNs and therefore may play distinct functional roles in parasympathetic control of the heart.
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Affiliation(s)
- Olga Dergacheva
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA.
| | - Akihiro Yamanaka
- Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan
| | - Alan R Schwartz
- Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | | | - David Mendelowitz
- Department of Pharmacology and Physiology, The George Washington University, 2300 Eye Street, NW, Washington, DC 20037, USA
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Hirota K. Sepsis and the orexin system. J Anesth 2016; 30:919-922. [PMID: 27580992 DOI: 10.1007/s00540-016-2246-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 08/24/2016] [Indexed: 01/15/2023]
Affiliation(s)
- Kazuyoshi Hirota
- Department of Anesthesiology, Hirosaki University Graduate School of Medicine, Hirosaki, 036-8562, Japan.
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Martin EJ, Hernandez ME, Hayward LF. Blockade of orexin receptors attenuates the cardiovascular response to air-jet stress in spontaneously hypertensive rats. Auton Neurosci 2016; 201:8-16. [PMID: 27591948 DOI: 10.1016/j.autneu.2016.08.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/15/2016] [Accepted: 08/19/2016] [Indexed: 12/28/2022]
Abstract
This study tested the hypothesis that orexin plays a role in the elevated pressor response to acute stress in the spontaneously hypertensive rat (SHR). The pressor response to air jet stress (AJS) (n=11/group) was 2.5 times greater in vehicle treated SHR versus Wistar (WIS) rats. Systemic delivery of 30mg/kg of the dual orexin receptor antagonist almorexant did not significantly change resting mean arterial pressure (MAP) but did attenuate the pressor response elicited by AJS to a greater extent in the SHR compared to the Wistar rats (~65% versus ~33% reduction respectively; n=6/group). Alternatively 100mg/kg almorexant reduced resting MAP in the SHR (~25mm Hg drop) and attenuated both the heart rate (HR; ~50% reduction) and MAP (~62% reduction) response to AJS in both strains (n=6/group). Systemic application of SB-334867 (3mg/kg), an orexin receptor type 1 antagonist (n=5/group), selectively reduced resting MAP and attenuated the HR response to AJS in the SHR but had no effect on the pressor response in either strain. The potential role of endogenous orexin release in cardiovascular control in the SHR was linked to a significant increase in brain-derived neurotrophic factor mRNA expression in the hypothalamus and elevated orexin receptor expression (type 2 only) in the dorsal pons when compared to WIS (n=4/group). These results demonstrate that the exaggerated pressor response in the SHR to stress is linked to increased orexin receptor activation and possibly altered orexin receptor expression in the dorsal pons and BDNF expression in the hypothalamus.
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Affiliation(s)
- Eric J Martin
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
| | - Morgan E Hernandez
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
| | - Linda F Hayward
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States.
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Orexin, Stress and Central Cardiovascular Control. A Link with Hypertension? Neurosci Biobehav Rev 2016; 74:376-392. [PMID: 27477446 DOI: 10.1016/j.neubiorev.2016.06.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 05/28/2016] [Accepted: 06/13/2016] [Indexed: 01/28/2023]
Abstract
Orexin, the arousal peptide, originates from neurons located in an area of the dorsal hypothalamus well known for integrating defense responses and their cardiovascular component. Orexin neurons, which are driven in large part by the limbic forebrain, send projections to many regions in the brain, including regions involved in cardiovascular control, as far down as sympathetic preganglionic neurons in the spinal cord. Central injections of orexin evoke sympathetically mediated cardiovascular responses. Conversely, blockade of orexin receptors reduce the cardiovascular responses to acute stressors, preferentially of a psychological nature. More importantly, lasting upregulation of orexin signaling can lead to a hypertensive state. This can be observed in rats exposed to chronic stress as well as in strains known to display spontaneous hypertension such as the spontaneously hypertensive rat (SHR) or the hypertensive BPH/2J Schlager mouse. Thus, there is a link between orexin, stress and hypertension, and orexin upregulation could be a factor in the development of essential hypertension. Orexin receptor antagonists have anti-hypertensive effects that could be of clinical use.
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Göktalay G, Millington WR. Hypovolemic hemorrhage induces Fos expression in the rat hypothalamus: Evidence for involvement of the lateral hypothalamus in the decompensatory phase of hemorrhage. Neuroscience 2016; 322:464-78. [PMID: 26947128 DOI: 10.1016/j.neuroscience.2016.02.068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 02/10/2016] [Accepted: 02/27/2016] [Indexed: 01/02/2023]
Abstract
This study tested the hypothesis that the hypothalamus participates in the decompensatory phase of hemorrhage by measuring Fos immunoreactivity and by inhibiting neuronal activity in selected hypothalamic nuclei with lidocaine or cobalt chloride. Previously, we reported that inactivation of the arcuate nucleus inhibited, but did not fully prevent, the fall in arterial pressure evoked by hypotensive hemorrhage. Here, we report that hemorrhage (2.2 ml/100g body weight over 20 min) induced Fos expression in a high percentage of cells in the paraventricular, supraoptic and arcuate nuclei of the hypothalamus as shown previously. Lower densities of Fos immunoreactive cells were also found in the medial preoptic area (mPOA), anterior hypothalamus, lateral hypothalamus (LH), dorsomedial hypothalamus, ventromedial hypothalamus (VMH) and posterior hypothalamus. Bilateral injection of lidocaine (2%; 0.1 μl or 0.3 μl) or cobalt chloride (5mM; 0.3 μl) into the tuberal portion of the LH immediately before hemorrhage was initiated reduced the magnitude of hemorrhagic hypotension and bradycardia significantly. Lidocaine injection into the VMH also attenuated the fall in arterial pressure and heart rate evoked by hemorrhage although inactivation of the mPOA or rostral LH was ineffective. These findings indicate that hemorrhage activates neurons throughout much of the hypothalamus and that a relatively broad area of the hypothalamus, extending from the arcuate nucleus laterally through the caudal VMH and tuberal LH, plays an important role in the decompensatory phase of hemorrhage.
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Affiliation(s)
- G Göktalay
- Department of Medical Pharmacology, Uludag University, Faculty of Medicine, Bursa, Turkey
| | - W R Millington
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY, United States.
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36
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Major Autonomic Neuroregulatory Pathways Underlying Short- and Long-Term Control of Cardiovascular Function. Curr Hypertens Rep 2016; 18:18. [DOI: 10.1007/s11906-016-0625-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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37
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Beig MI, Horiuchi J, Dampney RAL, Carrive P. Both Ox1R and Ox2R orexin receptors contribute to the cardiorespiratory response evoked from the perifornical hypothalamus. Clin Exp Pharmacol Physiol 2015; 42:1059-67. [DOI: 10.1111/1440-1681.12461] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/23/2015] [Accepted: 07/09/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Mirza I Beig
- School of Medical Sciences; University of New South Wales; Sydney NSW Australia
| | - Jouji Horiuchi
- Department of Biomedical Engineering; Toyo University; Kawagoe Saitama Japan
| | - Roger AL Dampney
- School of Medical Sciences; University of New South Wales; Sydney NSW Australia
- School of Medical Sciences and Bosch Institute for Biomedical Research; University of Sydney; Sydney NSW Australia
| | - Pascal Carrive
- School of Medical Sciences; University of New South Wales; Sydney NSW Australia
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38
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Hayward LF, Hampton EE, Ferreira LF, Christou DD, Yoo JK, Hernandez ME, Martin EJ. Chronic heart failure alters orexin and melanin concentrating hormone but not corticotrophin releasing hormone-related gene expression in the brain of male Lewis rats. Neuropeptides 2015; 52:67-72. [PMID: 26111703 DOI: 10.1016/j.npep.2015.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 11/27/2022]
Abstract
OBJECTIVE The aim of this study was to investigate the effect of chronic heart failure (HF; 16 weeks post left coronary artery ligation) on the brain's orexin (ORX) and related neuropeptide systems. METHODS Indicators of cardiac function, including the percent fractional shortening (%FS) left ventricular posterior wall shortening velocity (LVPWSV) were assessed via echocardiography at 16 weeks post myocardial infarction or sham treatment in male Lewis rats (n=5/group). Changes in gene expression in HF versus control (CON) groups were quantified by real-time PCR in the hypothalamus, amygdala and dorsal pons. RESULTS HF significantly reduced both the %FS and LVPWSV when compared to CON animals (P<0.02). In the hypothalamus ORX gene expression was significantly reduced in HF and correlated with changes in cardiac function when compared to CON (P<0.02). No significant changes in hypothalamic ORX receptor (type 1 or type 2) gene expression were identified. Alternatively hypothalamic melanin concentrating hormone (MCH) gene expression was significantly upregulated in HF animals and negatively correlated with LVPWSV (P<0.006). In both the amygdala and dorsal pons ORX type 2 receptor expression was significantly down-regulated in HF compared to CON. ORX receptor type 1, CRH and CRH type 1 and type 2 receptor expressions were unchanged by HF in all brain regions analyzed. CONCLUSION These observations support previous work demonstrating that cardiovascular disease modulates the ORX system and identify that in the case of chronic HF the ORX system is altered in parallel with changes in MCH expression but independent of any significant changes in the central CRH system. This raises the new possibility that ORX and MCH systems may play an important role in the pathophysiology of HF.
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Affiliation(s)
- Linda F Hayward
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
| | - Erin E Hampton
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
| | - Leonardo F Ferreira
- University of Florida, College of Health and Human Performance, Dept. of Applied Physiology and Kinesiology, Gainesville, FL 32610, United States
| | - Demetra D Christou
- University of Florida, College of Health and Human Performance, Dept. of Applied Physiology and Kinesiology, Gainesville, FL 32610, United States
| | - Jeung-Ki Yoo
- University of Florida, College of Health and Human Performance, Dept. of Applied Physiology and Kinesiology, Gainesville, FL 32610, United States
| | - Morgan E Hernandez
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
| | - Eric J Martin
- University of Florida, College of Veterinary Medicine, Dept. of Physiological Sciences, Gainesville, FL 32610, United States
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Clifford L, Dampney BW, Carrive P. Spontaneously hypertensive rats have more orexin neurons in their medial hypothalamus than normotensive rats. Exp Physiol 2015; 100:388-98. [PMID: 25640802 DOI: 10.1113/expphysiol.2014.084137] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/07/2015] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Blockade of orexin receptors reduces blood pressure in spontaneously hypertensive rats (SHRs) but not in normotensive Wistar-Kyoto (WKY) rats, suggesting that upregulation of orexin signalling underlies the hypertensive phenotype of the SHR. However, it is not known what causes this upregulation. What is the main finding and its importance? Using orexin immunolabelling, we show that SHRs have 20% more orexin neurons than normotensive WKY and Wistar rats in the medial hypothalamus, which is a good match to their blood pressure phenotype. In contrast, there is no such match for the orexin neurons of the lateral hypothalamus. Essential hypertension may be linked to an increase in orexin neurons in the medial hypothalamus. The neuropeptide orexin contributes to the regulation of blood pressure as part of its role in the control of arousal during wakefulness and motivated behaviour (including responses to psychological stress). Recent work shows that pharmacological blockade of orexin receptors reduces blood pressure in spontaneously hypertensive rats (SHRs) but not in normotensive Wistar-Kyoto (WKY) rats. It is not clear why orexin signalling is upregulated in the SHR, but one possibility is that these animals have more orexin neurons than their normotensive WKY and Wistar relatives. To test this possibility, SHRs, WKY and Wistar male rats (6-16 weeks old) were killed, perfused and their brains sectioned and immunolabelled for orexin A. Labelled neurons were plotted and counted in the six best labelled hemisections (120 μm apart) of each brain. There were significantly more orexin neurons (+20%) in the medial hypothalamus (medial to fornix) of SHRs compared with WKY and Wistar rats (126 ± 4 versus 106 ± 5 and 104 ± 5 per hemisection, respectively, P < 0.05), which matches well the blood pressure phenotypes. In contrast, counts in the lateral hypothalamus did not match the blood pressure phenotypes (69 ± 2 versus 50 ± 3 and 76 ± 4, respectively). The results support the idea that orexin signalling is upregulated in the SHR and suggest that this is due, at least in part, to a greater number of orexin neurons in the medial hypothalamus. These medial orexin neurons, which are also involved in hyperarousal and stress responses, may contribute to the development of essential hypertension.
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Affiliation(s)
- Liam Clifford
- School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
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Mahler SV, Moorman DE, Smith RJ, James MH, Aston-Jones G. Motivational activation: a unifying hypothesis of orexin/hypocretin function. Nat Neurosci 2014; 17:1298-303. [PMID: 25254979 PMCID: PMC4335648 DOI: 10.1038/nn.3810] [Citation(s) in RCA: 264] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 08/19/2014] [Indexed: 12/15/2022]
Abstract
Orexins (hypocretins) are two peptides (orexin A and B) produced from the pre-pro-orexin precursor and expressed in a limited region of dorsolateral hypothalamus. Orexins were originally thought to specifically mediate feeding and promote wakefulness, but it is now clear that they participate in a wide range of behavioral and physiological processes under select circumstances. Orexins primarily mediate behavior under situations of high motivational relevance, such as during physiological need states, exposure to threats or reward opportunities. We hypothesize that many behavioral functions of orexins (including regulation of sleep/wake cycling) reflect a fundamentally integrated function for orexins in translating motivational activation into organized suites of psychological and physiological processes supporting adaptive behaviors. We also discuss how numerous forms of neural heterogeneity modulate this function, allowing orexin neurons to organize diverse, adaptive responses in a variety of motivationally relevant situations. Thus, the involvement of orexins in diverse behaviors may reflect a common underlying function for this peptide system.
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Affiliation(s)
- Stephen V Mahler
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - David E Moorman
- 1] Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA. [2] Department of Psychological and Brain Sciences, University of Massachusetts Amherst, Amherst, Massachusetts, USA
| | - Rachel J Smith
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Morgan H James
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Gary Aston-Jones
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina, USA
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Paul ED, Johnson PL, Shekhar A, Lowry CA. The Deakin/Graeff hypothesis: focus on serotonergic inhibition of panic. Neurosci Biobehav Rev 2014; 46 Pt 3:379-96. [PMID: 24661986 PMCID: PMC4170046 DOI: 10.1016/j.neubiorev.2014.03.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 02/15/2014] [Accepted: 03/01/2014] [Indexed: 12/20/2022]
Abstract
The Deakin/Graeff hypothesis proposes that different subpopulations of serotonergic neurons through topographically organized projections to forebrain and brainstem structures modulate the response to acute and chronic stressors, and that dysfunction of these neurons increases vulnerability to affective and anxiety disorders, including panic disorder. We outline evidence supporting the existence of a serotonergic system originally discussed by Deakin/Graeff that is implicated in the inhibition of panic-like behavioral and physiological responses. Evidence supporting this panic inhibition system comes from the following observations: (1) serotonergic neurons located in the 'ventrolateral dorsal raphe nucleus' (DRVL) as well as the ventrolateral periaqueductal gray (VLPAG) inhibit dorsal periaqueductal gray-elicited panic-like responses; (2) chronic, but not acute, antidepressant treatment potentiates serotonin's panicolytic effect; (3) contextual fear activates a central nucleus of the amygdala-DRVL/VLPAG circuit implicated in mediating freezing and inhibiting panic-like escape behaviors; (4) DRVL/VLPAG serotonergic neurons are central chemoreceptors and modulate the behavioral and cardiorespiratory response to panicogenic agents such as sodium lactate and CO2. Implications of the panic inhibition system are discussed.
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Affiliation(s)
- Evan D Paul
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309-0354, USA.
| | - Philip L Johnson
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309-0354, USA.
| | - Anantha Shekhar
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309-0354, USA.
| | - Christopher A Lowry
- Department of Integrative Physiology and Center for Neuroscience, University of Colorado Boulder, Boulder, CO 80309-0354, USA.
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Both Ox1r and Ox2r orexin receptors contribute to the cardiovascular and locomotor components of the novelty stress response in the rat. Neuropharmacology 2014; 89:146-56. [PMID: 25239810 DOI: 10.1016/j.neuropharm.2014.09.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 09/06/2014] [Accepted: 09/08/2014] [Indexed: 11/22/2022]
Abstract
Orexin contributes to the expression of the cardiovascular and behavioural response of some forms of stress, including novelty stress. Thus, Almorexant, a dual receptor antagonist that blocks the two known orexin receptors, Ox1R and Ox2R, reduces these responses. However, it is not known if the reduction results from blockade of one receptor only or both. To answer this question, the selective Ox1R antagonist ACT335827 and the selective Ox2R antagonist EMPA were injected intragastrically (300 mg/kg) or intraperitoneally (30 and 100 mg/kg) either alone or as a cocktail and compared to Almorexant in rats exposed to novelty stress. Cardiovascular and locomotor responses were recorded by radio-telemetry. Triple immunolabelling was also conducted to establish the distribution of Ox1R and Ox2R in sympathetic preganglionic neurons and orexin neurons. Intraperitoneal injections of ACT335827 (100 mg/kg) reduced the pressor and tachycardic but not the locomotor response of novelty (by 32% and 48%, respectively). Intraperitoneal injections of EMPA (100 mg/kg) only reduced the pressor response (42%). However when given together, ACT335827 and EMPA reduced all 3 components (65%, 60% and 57% of the tachycardic, pressor and locomotor responses, respectively) as Almorexant (100 mg/kg) did (69%, 87% and 72%, respectively). Triple immunolabelling revealed that sympathetic preganglionic neurons were mainly Ox1R positive only while orexin neurons were both Ox1R and Ox2R positive. This study shows that orexin's contribution to the cardiovascular and locomotor components of the novelty stress response is not mediated by one receptor alone, but by both receptors and at different levels of the neuraxis.
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Darwinkel A, Stanić D, Booth LC, May CN, Lawrence AJ, Yao ST. Distribution of orexin-1 receptor-green fluorescent protein- (OX1-GFP) expressing neurons in the mouse brain stem and pons: Co-localization with tyrosine hydroxylase and neuronal nitric oxide synthase. Neuroscience 2014; 278:253-64. [PMID: 25168728 DOI: 10.1016/j.neuroscience.2014.08.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 11/16/2022]
Abstract
We used a reporter mouse line in which green fluorescent protein (GFP) was inserted into the orexin-1 receptor (OX1) locus to systematically map the neuroanatomical distribution of the OX1 receptor in the mouse brainstem and pons. Here, we show that the OX1 receptor is expressed in a select subset of medullary and pontine nuclei. In the medulla, we observed OX1-GFP expression in the cuneate, gracile, dorsal motor nucleus of the vagus (10N), nucleus of the solitary tract and medullary raphe areas. In the pons, the greatest expression was found in the locus coeruleus (LC) and dorsal raphe nucleus (DRN). High to moderate expression was found in the pedunculopontine tegmental nucleus (PPTg), laterodorsal tegmental nucleus, A5 noradrenergic cell group (A5) and the periaqueductal gray. Double-labeling with neuronal nitric oxide synthase (NOS1) revealed extensive co-localization in cell bodies and fibers of the 10N, A5 cell group and the PPTg. Double-staining with tyrosine hydroxylase revealed extensive co-expression in the LC, DRN and the lateral paragigantocellularis cell group in the ventral medulla. Our findings faithfully recapitulate the findings of OX1 mRNA expression previously reported. This is the first study to systematically map the neuroanatomical distribution of OX1 receptors within the mouse hindbrain and suggest that this OX1-GFP transgenic reporter mouse line might be a useful tool with which to study the neuroanatomy and physiology of OX1 receptor-expressing cells.
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Affiliation(s)
- A Darwinkel
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia
| | - D Stanić
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia
| | - L C Booth
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia
| | - C N May
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia
| | - A J Lawrence
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia
| | - S T Yao
- Florey Institute of Neuroscience and Mental Health, Howard Florey Laboratories, University of Melbourne, Royal Parade, VIC 3010, Australia.
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Mohammed M, Ootsuka Y, Yanagisawa M, Blessing W. Reduced brown adipose tissue thermogenesis during environmental interactions in transgenic rats with ataxin-3-mediated ablation of hypothalamic orexin neurons. Am J Physiol Regul Integr Comp Physiol 2014; 307:R978-89. [PMID: 25324552 DOI: 10.1152/ajpregu.00260.2014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Thermogenesis in brown adipose tissue (BAT) contributes to substantial increases in body temperature evoked by threatening or emotional stimuli. BAT thermogenesis also contributes to increases in body temperature that occur during active phases of the basic rest-activity cycle (BRAC), as part of normal daily life. Hypothalamic orexin-synthesizing neurons influence many physiological and behavioral variables, including BAT and body temperature. In conscious unrestrained animals maintained for 3 days in a quiet environment (24-26°C) with ad libitum food and water, we compared temperatures in transgenic rats with ablation of orexin neurons induced by expression of ataxin-3 (Orx_Ab) with wild-type (WT) rats. Both baseline BAT temperature and baseline body temperature, measured at the onset of BRAC episodes, were similar in Orx_Ab and WT rats. The time interval between BRAC episodes was also similar in the two groups. However, the initial slopes and amplitudes of BRAC-related increases in BAT and body temperature were reduced in Orx_Ab rats. Similarly, the initial slopes and amplitudes of the increases in BAT temperatures induced by sudden exposure to an intruder rat (freely moving or confined to a small cage) or by sudden exposure to live cockroaches were reduced in resident Orx_Ab rats. Constriction of the tail artery induced by salient alerting stimuli was also reduced in Orx_Ab rats. Our results suggest that orexin-synthesizing neurons contribute to the intensity with which rats interact with the external environment, both when the interaction is "spontaneous" and when the interaction is provoked by threatening or salient environmental events.
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Affiliation(s)
- Mazher Mohammed
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
| | - Youichirou Ootsuka
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
| | - Masashi Yanagisawa
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Japan; and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, Texas
| | - William Blessing
- Centre for Neuroscience, Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia; and
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Hypothalamic orexin-A (hypocretin-1) neuronal projections to the vestibular complex and cerebellum in the rat. Brain Res 2014; 1579:20-34. [PMID: 25017945 DOI: 10.1016/j.brainres.2014.07.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/24/2014] [Accepted: 07/04/2014] [Indexed: 12/31/2022]
Abstract
Immunohistochemistry combined with retrograde tract-tracing techniques were used to investigate the distribution of orexin-A (OX-A)- and OX-A receptor-like (OX1) immunoreactivity within the vestibular complex and cerebellum, and the location of hypothalamic OX-A neurons sending axonal projections to these regions in the Wistar rat. OX-A immunoreactive fibers and presumptive terminals were found throughout the medial (MVe) and lateral (LVe) vestibular nuclei. Light fiber labeling was also observed in the spinal and superior vestibular nuclei. Within the cerebellum, dense fiber and presumptive terminal labeling was observed in the medial cerebellar nucleus (Med; fastigial nucleus), with less dense labeling in the interposed (Int) and lateral cerebellar nuclei (Lat; dentate nucleus). A few scattered OX-A immunoreactive fibers were also observed throughout the cortex of the paraflocculus. OX1-like immunoreactivity was found densely concentrated within LVe, moderate in MVe, and scattered within the spinal and superior vestibular nuclei. Within the cerebellum, OX1-like immunoreactivity was also observed densely within Med and in the dorsolateral aspects of Int. Additionally, OX1 like-labeling was found in Lat, and within the granular layer of the caudal paraflocculus cerebellar cortex. Fluorogold (FG) microinjected into these vestibular and cerebellar regions resulted in retrogradely labeled neurons throughout the ipsilateral hypothalamus. Retrogradely labeled neurons containing OX-A like immunoreactivity were observed dorsal and caudal to the anterior hypothalamic nucleus and extending laterally into the lateral hypothalamic area, with the largest number clustered around the dorsal aspects of the fornix in the perifornical area. A few FG OX-A like-immunoreactive neurons were also observed scattered throughout the dorsomedial, and posterior hypothalamic nuclei. These data indicate that axons from OX-A neurons terminate within the vestibular complex and deep cerebellar nuclei of the cerebellum and although the function of these pathways is unknown, they likely represent pathways by which hypothalamic OX-A containing neurons co-ordinate vestibulo-cerebellar motor and autonomic functions associated with ingestive behaviors.
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Steiner MA, Winrow CJ. Opportunities and perspectives for developing orexin receptor antagonists. Front Neurosci 2014; 8:158. [PMID: 24971050 PMCID: PMC4054497 DOI: 10.3389/fnins.2014.00158] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 05/26/2014] [Indexed: 12/16/2022] Open
Affiliation(s)
- Michel A Steiner
- Actelion Pharmaceuticals Ltd., Department of Central Nervous System (CNS) Pharmacology Allschwil, Switzerland
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