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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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Faesel N, Koch M, Fendt M. Orexin deficiency modulates the dipsogenic effects of angiotensin II in a sex-dependent manner. Peptides 2024; 171:171127. [PMID: 38043589 DOI: 10.1016/j.peptides.2023.171127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 11/10/2023] [Accepted: 11/28/2023] [Indexed: 12/05/2023]
Abstract
The orexin (hypocretin) neuropeptide system is an important regulator of ingestive behaviors, i.e., it promotes food and water intake. Here, we investigated the role of orexin in drinking induced by the potent dipsogen angiotensin II (ANG II). Specifically, male and female orexin-deficient mice received intracerebroventricular (ICV) injections of ANG II, followed by measuring their water intake within 15 min. We found that lower doses of ANG II (100 ng) significantly stimulated drinking in males but not in females, indicating a general sex-dependent effect that was not affected by orexin deficiency. However, higher doses of ANG II (500 ng) were sufficient to induce drinking in female wild-type mice, while female orexin-deficient mice still did not respond to the dipsogenic properties of ANG II. In conclusion, these results suggest sex-dependent effects in ANG II-induced drinking and further support the sexual dimorphism of orexin system functions.
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Affiliation(s)
- Nadine Faesel
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany; Department of Neuropharmacology, Brain Research Institute, University of Bremen, Hochschulring 18, D-28359 Bremen, Germany.
| | - Michael Koch
- Department of Neuropharmacology, Brain Research Institute, University of Bremen, Hochschulring 18, D-28359 Bremen, Germany.
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, Leipziger Straße 44, D-39120 Magdeburg, Germany.
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Todini L, Fantuz F. Thirst: neuroendocrine regulation in mammals. Vet Res Commun 2023; 47:1085-1101. [PMID: 36932281 DOI: 10.1007/s11259-023-10104-2] [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: 12/05/2022] [Accepted: 03/13/2023] [Indexed: 03/19/2023]
Abstract
Animals can sense their changing internal needs and then generate specific physiological and behavioural responses in order to restore homeostasis. Water-saline homeostasis derives from balances of water and sodium intake and output (drinking and diuresis, salt appetite and natriuresis), maintaining an appropriate composition and volume of extracellular fluid. Thirst is the sensation which drives to seek and consume water, regulated in the central nervous system by both neural and chemical signals. Water and electrolyte homeostasis depends on finely tuned physiological mechanisms, mainly susceptible to plasma Na+ concentration and osmotic pressure, but also to blood volume and arterial pressure. Increases of osmotic pressure as slight as 1-2% are enough to induce thirst ("homeostatic" or cellular), by activation of specialized osmoreceptors in the circumventricular organs, outside the blood-brain barrier. Presystemic anticipatory signals (by oropharyngeal or gastrointestinal receptors) inhibit thirst when fluids are ingested, or stimulate thirst associated with food intake. Hypovolemia, arterial hypotension, Angiotensin II stimulate thirst ("hypovolemic thirst", "extracellular dehydration"). Hypervolemia, hypertension, Atrial Natriuretic Peptide inhibit thirst. Circadian rhythms of thirst are also detectable, driven by suprachiasmatic nucleus in the hypothalamus. Such homeostasis and other fundamental physiological functions (cardiocircolatory, thermoregulation, food intake) are highly interdependent.
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Affiliation(s)
- Luca Todini
- Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via della Circonvallazione 93/95, 62024, Matelica, MC, Italy.
| | - Francesco Fantuz
- Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via della Circonvallazione 93/95, 62024, Matelica, MC, Italy
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Kurt G, Kodur N, Quiles CR, Reynolds C, Eagle A, Mayer T, Brown J, Makela A, Bugescu R, Seo HD, Carroll QE, Daniels D, Robison AJ, Mazei-Robison M, Leinninger G. Time to drink: Activating lateral hypothalamic area neurotensin neurons promotes intake of fluid over food in a time-dependent manner. Physiol Behav 2022; 247:113707. [PMID: 35063424 PMCID: PMC8844224 DOI: 10.1016/j.physbeh.2022.113707] [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: 08/05/2021] [Revised: 11/24/2021] [Accepted: 01/16/2022] [Indexed: 10/19/2022]
Abstract
The lateral hypothalamic area (LHA) is essential for ingestive behavior but has primarily been studied in modulating feeding, with comparatively scant attention on drinking. This is partly because most LHA neurons simultaneously promote feeding and drinking, suggesting that ingestive behaviors track together. A notable exception are LHA neurons expressing neurotensin (LHANts neurons): activating these neurons promotes water intake but modestly restrains feeding. Here we investigated the connectivity of LHANts neurons, their necessity and sufficiency for drinking and feeding, and how timing and resource availability influence their modulation of these behaviors. LHANts neurons project broadly throughout the brain, including to the lateral preoptic area (LPO), a brain region implicated in modulating drinking behavior. LHANts neurons also receive inputs from brain regions implicated in sensing hydration and energy status. While activation of LHANts neurons is not required to maintain homeostatic water or food intake, it selectively promotes drinking during the light cycle, when ingestive drive is low. Activating LHANts neurons during this period also increases willingness to work for water or palatable fluids, regardless of their caloric content. By contrast, LHANts neuronal activation during the dark cycle does not promote drinking, but suppresses feeding during this time. Finally, we demonstrate that the activation of the LHANts → LPO projection is sufficient to mediate drinking behavior, but does not suppress feeding as observed after generally activating all LHANts neurons. Overall, our work suggests how and when LHANts neurons oppositely modulate ingestive behaviors.
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Key Words
- ARC, Arcuate nucleus
- CEA, Central amygdala
- CNO, Clozapine N-Oxide
- CPP, Conditioned place preference
- DR, Dorsal raphe
- DREADD
- DREADD, Designer receptor exclusively activated by designer drugs
- FR-1, Fixed ratio-1
- LHA
- LHA(Nts), Lateral hypothalamic area neuotensin-expressing
- LHA, Lateral hypothalamic area
- LPO, Lateral preoptic area
- LT, Lateral terminalis
- LepRb, Long form of the leptin receptor
- MnPO, Median preoptic area
- ModRabies, Genetically modified rabies virus, EnvA-∆G-Rabies-mCherry
- NTS, Nucleus of solitary tract
- Nts, Neurotensin
- NtsR1, Neurotensin receptor-1
- NtsR2, Neurotensin receptor-2
- OVLT, Organum vasculosum lamina terminalis
- PAG, Periaqueductal gray
- PB, Parabrachial area
- PR, Progressive ratio
- PVH, Paraventricular nucleus of hypothalamus
- SFO, Subfornical organ
- SNc, Substantia nigra compacta
- SO, Supraoptic nucleus
- TVA, avian viral receptor protein
- VEH, Vehicle
- VTA, Ventral tegmental area
- WT, Wild type
- Water
- aCSF, Artificial cerebrospinal fluid
- body weight
- feeding
- homeostasis
- lHb, Lateral habenula
- lateral preoptic area (LPO)
- neurotensin receptor
- reward
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Affiliation(s)
- Gizem Kurt
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Nandan Kodur
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Chelsea Reynolds
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Andrew Eagle
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Tom Mayer
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Juliette Brown
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI 48824, USA
| | - Anna Makela
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Raluca Bugescu
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Harim Delgado Seo
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | - Quinn E Carroll
- Department of Psychology and the Center for Ingestive Behavior Research, University at Buffalo, the State University of New York, Buffalo, NY 14226, USA
| | - Derek Daniels
- Department of Psychology and the Center for Ingestive Behavior Research, University at Buffalo, the State University of New York, Buffalo, NY 14226, USA
| | - A J Robison
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA
| | | | - Gina Leinninger
- Department of Physiology, Michigan State University, East Lansing, MI 48824, USA.
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A Portable Biodevice to Monitor Salivary Conductivity for the Rapid Assessment of Fluid Status. J Pers Med 2021; 11:jpm11060577. [PMID: 34205354 PMCID: PMC8235451 DOI: 10.3390/jpm11060577] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/12/2021] [Accepted: 06/17/2021] [Indexed: 01/29/2023] Open
Abstract
The evaluation of fluid status can save adults from life-threatening conditions, but the current methods are invasive or time-consuming. Therefore, we developed a portable device for measuring salivary conductivity. This prospective observational study enrolled 20 volunteers with no history of systemic diseases. Participants were observed for 13 h, including water restriction for 12 h followed by rehydration with 1000 mL water within 1 h. Serum and urine biomarkers for fluid status, thirst scales, and salivary conductivity were collected during dehydration and rehydration. No significant differences in age, body mass index, glycohemoglobin, and estimated glomerular filtration rate were noted between sexes. Salivary conductivity increased after water restriction and decreased after rehydration. Similarly, urine osmolality, urine specific gravity, thirst intensity scales, and body weight followed the same trend and were statistically significant. The angiotensin-converting enzyme and aldosterone levels showed the same trend, without reaching statistical significance. The red blood cell count and hemoglobin concentration also followed the same trend. Analyzing the receiver operating characteristic curves, the area under the curve was 0.707 (95% confidence interval 0.542–0.873, p = 0.025). Using the Youden index, the optimal cutoff determined as 2678.09 μs/cm (sensitivity: 90%, specificity: 55%). This biodevice effectively screened dehydration among healthy adults.
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Abstract
Thirst is a highly potent drive that motivates organisms to seek out and consume balance-restoring stimuli. The detection of dehydration is well understood and involves signals of peripheral origin and the sampling of internal milieu by first order homeostatic neurons within the lamina terminalis-particularly glutamatergic neurons of the subfornical organ expressing CaMKIIa (SFOCaMKIIa). However, it remains unknown whether mesolimbic dopamine pathways that are critical for motivation and reinforcement integrate information from these "early" dehydration signals. We used in vivo fiber photometry in the ventral tegmental area and measured phasic dopamine responses to a water-predictive cue. Thirst, but not hunger, potentiated the phasic dopamine response to the water cue. In euvolemic rats, the dipsogenic hormone angiotensin II, but not the orexigenic hormone ghrelin, potentiated the dopamine response similarly to that observed in water-deprived rats. Chemogenetic manipulations of SFOCaMKIIa revealed bidirectional control of phasic dopamine signaling during cued water reward. Taking advantage of within-subject designs, we found predictive relationships between changes in cue-evoked dopamine response and changes in behavioral responses-supporting a role for dopamine in motivation induced by homeostatic need. Collectively, we reveal a putative mechanism for the invigoration of goal-directed behavior: internal milieu communicates to first order, need state-selective circuits to potentiate the mesolimbic dopamine system's response to cues predictive of restorative stimuli.
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D'Aquila PS, Elia D, Galistu A. Role of dopamine D 1-like and D 2-like receptors in the activation of ingestive behaviour in thirsty rats licking for water. Psychopharmacology (Berl) 2019; 236:3497-3512. [PMID: 31273401 DOI: 10.1007/s00213-019-05317-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/30/2019] [Indexed: 12/21/2022]
Abstract
RATIONALE Analysis of lick pattern for sucrose and NaCl and of the forced swimming response after dopamine antagonist administration led us to suggest that dopamine on D1-like receptors is involved in behavioural activation, and the level of activation is "reboosted" on the basis of an evaluation process involving D2-like receptors. Although some studies investigated licking microstructure for water after dopamine antagonists, the within-session time course of their effect was never investigated. OBJECTIVES The aims of this study were to further investigate the role of dopamine receptors in the mechanisms governing water ingestion, focussing on the within-session time course of the microstructure parameters, and to test the proposed hypothesis. MATERIALS AND METHODS The effects of the dopamine D1-like receptor antagonist SCH 23390 (0.01-0.04 mg/kg) and of the dopamine D2-like receptor antagonist raclopride (0.025-0.25 mg/kg) on licking microstructure for water were examined in 20-h water-deprived rats in 30-min sessions. RESULTS As previously observed with sucrose and NaCl, SCH 23390 reduced licking by reducing burst number, suggesting reduced behavioural activation. Moreover, it resulted in an increased burst size. Raclopride reduced the size of licking bursts, while their number was either increased or decreased depending on the dose. CONCLUSION The results support the suggestion that D1 receptors are involved in behavioural activation and D2 receptors are involved in a related evaluation process. Within the framework of the proposed hypothesis, the increased burst size after D1-like receptor blockade might be interpreted as a pro-hedonic effect consequent to the increased cost of the activation of the licking response.
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Affiliation(s)
- Paolo S D'Aquila
- Dipartimento di Scienze Biomediche, Università di Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy.
| | - Domenico Elia
- Dipartimento di Scienze Biomediche, Università di Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy
| | - Adriana Galistu
- Dipartimento di Scienze Biomediche, Università di Sassari, Viale San Pietro 43/b, 07100, Sassari, Italy
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Godfrey N, Borgland SL. Diversity in the lateral hypothalamic input to the ventral tegmental area. Neuropharmacology 2019; 154:4-12. [DOI: 10.1016/j.neuropharm.2019.05.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 04/15/2019] [Accepted: 05/13/2019] [Indexed: 12/29/2022]
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