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Speigel I, Patel K, Osman V, Hemmings HC. Volatile anesthetics inhibit presynaptic cGMP signaling to depress presynaptic excitability in rat hippocampal neurons. Neuropharmacology 2023; 240:109705. [PMID: 37683886 PMCID: PMC10772825 DOI: 10.1016/j.neuropharm.2023.109705] [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: 01/17/2022] [Revised: 07/21/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023]
Abstract
Volatile anesthetics alter presynaptic function through effects on Ca2+ influx and neurotransmitter release. These actions are proposed to play important roles in their pleiotropic neurophysiological effects including immobility, unconsciousness and amnesia. Nitric oxide and cyclic guanosine monophosphate (NO/cGMP) signaling has been implicated in presynaptic mechanisms, and disruption of NO/cGMP signaling has been shown to alter sensitivity to volatile anesthetics in vivo. We investigated volatile anesthetic actions NO/cGMP signaling in relation to presynaptic function in cultured rat hippocampal neurons using pharmacological tools and genetically encoded biosensors and sequestering probes of cGMP levels. Using the fluorescent cGMP biosensor cGull, we found that electrical stimulation-evoked NMDA-type glutamate receptor-independent presynaptic cGMP transients were inhibited 33.2% by isoflurane (0.51 mM) and 26.4% by sevoflurane (0.57 mM) (p < 0.0001) compared to control stimulation without anesthetic. Stimulation-evoked cGMP transients were blocked by the nonselective inhibitor of nitric oxide synthase N-ω-nitro-l-arginine, but not by the selective neuronal nitric oxide synthase inhibitor N5-(1-imino-3-butenyl)-l-ornithine. Isoflurane and sevoflurane inhibition of stimulation-evoked increases in presynaptic Ca2+ concentration, measured with synaptophysin-GCaMP6f, and of synaptic vesicle exocytosis, measured with synaptophysin-pHlourin, was attenuated in neurons expressing the cGMP scavenger protein sponge (inhibition of exocytosis reduced by 54% for isoflurane and by 53% for sevoflurane). The anesthetic-induced reduction in presynaptic excitability was partially occluded by inhibition of HCN channels, a cGMP-modulated excitatory ion channel that can facilitate glutamate release. We propose that volatile anesthetics depress presynaptic cGMP signaling and downstream effectors like HCN channels that are essential to presynaptic function and excitability. These findings identify novel mechanisms by which volatile anesthetics depress synaptic transmission via second messenger signaling involving the NO/cGMP pathway in hippocampal neurons.
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Affiliation(s)
- Iris Speigel
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Kishan Patel
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Vanessa Osman
- Department of Pharmacology, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, 10065, USA; Department of Pharmacology, Weill Cornell Medicine, New York, NY, 10065, USA.
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Yan H, Wang Y, Huo F, Yin C. Fast-Specific Fluorescent Probes to Visualize Norepinephrine Signaling Pathways and Its Flux in the Epileptic Mice Brain. J Am Chem Soc 2023; 145:3229-3237. [PMID: 36701205 DOI: 10.1021/jacs.2c13223] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Norepinephrine (NE) is synthesized in the locus coeruleus and widely projected throughout the brain and spinal cord. It regulates various actions and consciousness linked to a variety of neurological diseases. A "hunting-shooting" strategy was proposed in this work to improve the specificity and response rate of an NE fluorescent probe: 2-(cyclohex-2-en-1-ylidene)malononitrile derivatives were chosen as a fluorophore. To create a dual-site probe, an aldehyde group was added to the ortho of the ester group (or benzene sulfonate). Because of its excellent electrophilic activity, the aldehyde group could rapidly "hunt" the amino group and then form an intramolecular five-membered ring via the nucleophilic reaction with the β-hydroxyl group. The -NH- in the five-membered ring "shoots" the adjacent ester group, releasing the fluorophore and allowing for rapid and specific NE detection. The NE release and reuptake ″emetic″-″swallow″ transient process is captured and visualized under the action of the primary NE receptor drug. Furthermore, by introducing halogen into the fluorophore to lengthen the absorption wavelength, improve lipid solubility, and adjust the pKa appropriately, the probe successfully penetrated the blood-brain barrier (BBB). In situ synchronous probe imaging was used to detect the NE level in the brains of epileptic and normal mice, and abnormal expression of NE in the brain was discovered during epilepsy. Brain anatomy was used to examine the distribution and level changes of NE in various brain regions before and after epilepsy. This research provides useful tools and a theoretical foundation for diagnosing and treating central nervous system diseases early.
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Affiliation(s)
- Huming Yan
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Yuting Wang
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Fangjun Huo
- Research Institute of Applied Chemistry, Shanxi University, Taiyuan, Shanxi 030006, China
| | - Caixia Yin
- Key Laboratory of Chemical Biology and Molecular Engineering of Ministry of Education, Key Laboratory of Materials for Energy Conversion and Storage of Shanxi Province, Institute of Molecular Science, Shanxi University, Taiyuan, Shanxi 030006, China
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Dhillon SK, Gunn ER, Pedersen MV, Lear CA, Wassink G, Davidson JO, Gunn AJ, Bennet L. Alpha-adrenergic receptor activation after fetal hypoxia-ischaemia suppresses transient epileptiform activity and limits loss of oligodendrocytes and hippocampal neurons. J Cereb Blood Flow Metab 2023; 43:947-961. [PMID: 36703575 DOI: 10.1177/0271678x231153723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Exposure to hypoxic-ischaemia (HI) is consistently followed by a delayed fall in cerebral perfusion. In preterm fetal sheep this is associated with impaired cerebral oxygenation, consistent with mismatch between perfusion and metabolism. In the present study we tested the hypothesis that alpha-adrenergic inhibition after HI would improve cerebral perfusion, and so attenuate mismatch and reduce neural injury. Chronically instrumented preterm (0.7 gestation) fetal sheep received sham-HI (n = 10) or HI induced by complete umbilical cord occlusion for 25 minutes. From 15 minutes to 8 hours after HI, fetuses received either an intravenous infusion of a non-selective alpha-adrenergic antagonist, phentolamine (10 mg bolus, 10 mg/h infusion, n = 10), or saline (n = 10). Fetal brains were processed for histology 72 hours post-HI. Phentolamine infusion was associated with increased epileptiform transient activity and a greater fall in cerebral oxygenation in the early post-HI recovery phase. Histologically, phentolamine was associated with greater loss of oligodendrocytes and hippocampal neurons. In summary, contrary to our hypothesis, alpha-adrenergic inhibition increased epileptiform transient activity with an exaggerated fall in cerebral oxygenation, and increased neural injury, suggesting that alpha-adrenergic receptor activation after HI is an important endogenous neuroprotective mechanism.
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Affiliation(s)
| | - Eleanor R Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Mette V Pedersen
- Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | - Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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Alpha2-Adrenergic Receptors as a Pharmacological Target for Spike-Wave Epilepsy. Int J Mol Sci 2023; 24:ijms24021477. [PMID: 36674992 PMCID: PMC9862736 DOI: 10.3390/ijms24021477] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/30/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Spike-wave discharges are the hallmark of idiopathic generalized epilepsy. They are caused by a disorder in the thalamocortical network. Commercially available anti-epileptic drugs have pronounced side effects (i.e., sedation and gastroenterological concerns), which might result from a low selectivity to molecular targets. We suggest a specific subtype of adrenergic receptors (ARs) as a promising anti-epileptic molecular target. In rats with a predisposition to absence epilepsy, alpha2 ARs agonists provoke sedation and enhance spike-wave activity during transitions from awake/sedation. A number of studies together with our own observations bring evidence that the sedative and proepileptic effects require different alpha2 ARs subtypes activation. Here we introduce a new concept on target pharmacotherapy of absence epilepsy via alpha2B ARs which are presented almost exclusively in the thalamus. We discuss HCN and calcium channels as the most relevant cellular targets of alpha2 ARs involved in spike-wave activity generation.
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Liu L, Shang L, Jin D, Wu X, Long B. General anesthesia bullies the gut: a toxic relationship with dysbiosis and cognitive dysfunction. Psychopharmacology (Berl) 2022; 239:709-728. [PMID: 35187594 DOI: 10.1007/s00213-022-06096-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 02/15/2022] [Indexed: 12/12/2022]
Abstract
Perioperative neurocognitive disorder (PND) is a common surgery outcome affecting up to a third of the elderly patients, and it is associated with high morbidity and increased risk for Alzheimer's disease development. PND is characterized by cognitive impairment that can manifest acutely in the form of postoperative delirium (POD) or after hospital discharge as postoperative cognitive dysfunction (POCD). Although POD and POCD are clinically distinct, their development seems to be mediated by a systemic inflammatory reaction triggered by surgical trauma that leads to dysfunction of the blood-brain barrier and facilitates the occurrence of neuroinflammation. Recent studies have suggested that the gut microbiota composition may play a pivotal role in the PND development by modulating the risk of neuroinflammation establishment. In fact, modulation of gut microbiome composition with pre- and probiotics seems to be effective for the prevention and treatment of PND in animals. Interestingly, general anesthetics seem to have major responsibility on the gut microbiota composition changes following surgery and, consequently, can be an important element in the process of PND initiation. This concept represents an important milestone for the understanding of PND pathogenesis and may unveil new opportunities for the development of preventive or mitigatory strategies against the development of these conditions. The aim of this review is to discuss how anesthetics used in general anesthesia can interact and alter the gut microbiome composition and contribute to PND development by favoring the emergence of neuroinflammation.
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Affiliation(s)
- Lidan Liu
- Department of Anesthesiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China
| | - Lihua Shang
- Department of Anesthesiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China
| | - Dongxue Jin
- Department of Anesthesiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China
| | - Xiuying Wu
- Department of Anesthesiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China
| | - Bo Long
- Department of Anesthesiology, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang, 110004, Liaoning Province, China.
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Speigel IA, Hemmings HC. Selective inhibition of gamma aminobutyric acid release from mouse hippocampal interneurone subtypes by the volatile anaesthetic isoflurane. Br J Anaesth 2021; 127:587-599. [PMID: 34384592 DOI: 10.1016/j.bja.2021.06.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The cellular and molecular mechanisms by which general anaesthesia occurs is poorly understood. Hippocampal interneurone subpopulations, which are critical regulators of cognitive function, have diverse neurophysiological and synaptic properties, but their responses to anaesthetics are unclear. METHODS We used live-cell imaging of fluorescent biosensors expressed in mouse hippocampal neurones to delineate interneurone subtype-specific effects of isoflurane on synaptic vesicle exocytosis. The role of voltage-gated sodium channel (Nav) subtype expression in determining isoflurane sensitivity was probed by overexpression or knockdown of specific Nav subtypes in identified interneurones. RESULTS Clinically relevant concentrations of isoflurane differentially inhibited synaptic vesicle exocytosis: to 83.1% (11.7%) of control in parvalbumin-expressing interneurones, and to 58.6% (13.3%) and 64.5% (8.5%) of control in somatostatin-expressing interneurones and glutamatergic neurones, respectively. The relative expression of Nav1.1 (associated with lower sensitivity) and Nav1.6 (associated with higher sensitivity) determined the sensitivity of exocytosis to isoflurane. CONCLUSIONS Isoflurane inhibits synaptic vesicle exocytosis from hippocampal glutamatergic neurones and GABAergic interneurones in a cell-type-specific manner depending on their expression of voltage-gated sodium channel subtypes.
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Affiliation(s)
- Iris A Speigel
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA.
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA
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Lu J, Wang X, Feng Z, Chen Y, Wen D, Liu Z. The protective effect of isoflurane pretreatment on liver IRI by suppressing noncanonical pyroptosis of liver macrophages. Int Immunopharmacol 2021; 99:107977. [PMID: 34332342 DOI: 10.1016/j.intimp.2021.107977] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 06/24/2021] [Accepted: 07/08/2021] [Indexed: 11/18/2022]
Abstract
BACKGROUND Liver ischaemia-reperfusion injury (IRI) is a major complication in the perioperative period and often leads to liver failure and even systemic inflammation. Sufficient evidence has demonstrated that isoflurane has anti-inflammatory effects. We aimed to determine whether isoflurane pretreatment protects against liver IRI and to investigate the mechanisms involved in this protection. METHODS Male C57BL/6 mice were pretreated with or without isoflurane and subjected to 90 min of 70% liver ischaemia, followed by reperfusion for 6 h. Liver tissues and serum were analysed to assess liver IRI. To probe the mechanisms, liver macrophages isolated from C57BL/6 mice were pretreated with or without emulsified isoflurane for 30 min before incubation with 1 µg/ml lipopolysaccharide (LPS) for 24 h. Inflammatory cytokine production, intracellular Ca2+ levels, caspase-11 expression, NF-κB transcription, and NLRP3 inflammasome activation were assessed by ELISA, an intracellular Ca2+ concentration assay, immunohistochemistry, or Western blotting. RESULTS Isoflurane preconditioning significantly relieved liver IRI in mice and LPS-induced inflammation in liver macrophages. Additionally, isoflurane pretreatment inhibited caspase-11 expression and noncanonical pyroptosis-related production of cytokines (IL-1β and IL-18). Interestingly, isoflurane preconditioning reduced intracellular Ca2+ levels, NF-κB translocation, and NLRP3 inflammasome activation in LPS-induced macrophages. Our results indicated that isoflurane preconditioning ameliorated liver IRI by suppressing noncanonical pyroptosis in liver macrophages. These findings suggest that isoflurane could be a pharmacological agent for liver IRI prevention and thus deserves more attention and further investigation.
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Affiliation(s)
- Jiao Lu
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China
| | - Xiaoying Wang
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China; The Third Affliated Hospital of Chongqing Medical University, Chongqing 40010, China
| | - Zhihao Feng
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China
| | - Yucheng Chen
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China
| | - Diguang Wen
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China
| | - Zuojin Liu
- Department of Hepatobiliary Surgery, Second Affiliated Hospital, Chongqing Medical University, Chongqing 40010, China.
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Bukharaeva E, Khuzakhmetova V, Dmitrieva S, Tsentsevitsky A. Adrenoceptors Modulate Cholinergic Synaptic Transmission at the Neuromuscular Junction. Int J Mol Sci 2021; 22:ijms22094611. [PMID: 33924758 PMCID: PMC8124642 DOI: 10.3390/ijms22094611] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/26/2021] [Indexed: 02/07/2023] Open
Abstract
Adrenoceptor activators and blockers are widely used clinically for the treatment of cardiovascular and pulmonary disorders. More recently, adrenergic agents have also been used to treat neurodegenerative diseases. Recent studies indicate a location of sympathetic varicosities in close proximity to neuromuscular junctions. The pressing question is whether there could be any effects of endo- or exogenous catecholamines on cholinergic neuromuscular transmission. It was shown that the pharmacological stimulation of adrenoceptors, as well as sympathectomy, can affect both acetylcholine release from motor nerve terminals and the functioning of postsynaptic acetylcholine receptors. In this review, we discuss the recent data regarding the effects of adrenergic drugs on neurotransmission at the neuromuscular junction. The elucidation of the molecular mechanisms by which the clinically relevant adrenomimetics and adrenoblockers regulate quantal acetylcholine release from the presynaptic nerve terminals and postsynaptic sensitivity may help in the design of highly effective and well-tolerated sympathomimetics for treating a number of neurodegenerative diseases accompanied by synaptic defects.
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Ahmadirad N, Fathollahi Y, Janahmadi M, Ghasemi Z, Shojaei A, Rezaei M, Barkley V, Mirnajafi-Zadeh J. The role of α adrenergic receptors in mediating the inhibitory effect of electrical brain stimulation on epileptiform activity in rat hippocampal slices. Brain Res 2021; 1765:147492. [PMID: 33887250 DOI: 10.1016/j.brainres.2021.147492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 04/06/2021] [Accepted: 04/14/2021] [Indexed: 10/21/2022]
Abstract
The Inhibitory effect of electrical low-frequency stimulation (LFS) on neuronal excitability and seizure occurrence has been indicated in experimental models, but the precise mechanism has not established. This investigation was intended to figure out the role of α1 and α2 adrenergic receptors in LFS' inhibitory effect on neuronal excitability. Epileptiform activity induced in an in vitro rat hippocampal slice preparation by high K+ ACSF and LFS (900 square wave pulses at 1 Hz) was administered at the beginning of epileptiform activity to the Schaffer collaterals. In CA1 pyramidal neurons, the electrophysiological properties were measured at the baseline, before high K+ ACSF washout, and at 15 min after high K+ ACSF washout using whole-cell, patch-clamp recording. Results indicated that after high K+ ACSF washout, prazosine (10 µM; α1 adrenergic receptor antagonist) and yohimbine (5 µM; α2 adrenergic receptor antagonist) suppressed the LFS' effect of reducing rheobase current and utilization time following depolarizing ramp current, the latency to the first spike following a depolarizing current and latency to the first rebound action potential following hyperpolarizing current pulses. Thus, it may be proposed that LFS' inhibitory action on the neuronal hyperexcitability, in some way, is mediated by α1 and α2 adrenergic receptors.
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Affiliation(s)
- Nooshin Ahmadirad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Yaghoub Fathollahi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mahyar Janahmadi
- Department of Physiology, Faculty of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zahra Ghasemi
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Amir Shojaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Mahmoud Rezaei
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Victoria Barkley
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Javad Mirnajafi-Zadeh
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Institute for Brain Sciences and Cognition, Tarbiat Modares University, Tehran, Iran.
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Evdokimovskii EV, Jeon R, Park S, Pimenov OY, Alekseev AE. Role of α2-Adrenoceptor Subtypes in Suppression of L-Type Ca 2+ Current in Mouse Cardiac Myocytes. Int J Mol Sci 2021; 22:ijms22084135. [PMID: 33923625 PMCID: PMC8072751 DOI: 10.3390/ijms22084135] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/07/2021] [Accepted: 04/14/2021] [Indexed: 12/31/2022] Open
Abstract
Sarcolemmal α2 adrenoceptors (α2-AR), represented by α2A, α2B and α2C isoforms, can safeguard cardiac muscle under sympathoadrenergic surge by governing Ca2+ handling and contractility of cardiomyocytes. Cardiomyocyte-specific targeting of α2-AR would provide cardiac muscle-delimited stress control and enhance the efficacy of cardiac malfunction treatments. However, little is known about the specific contribution of the α2-AR subtypes in modulating cardiomyocyte functions. Herein, we analyzed the expression profile of α2A, α2B and α2C subtypes in mouse ventricle and conducted electrophysiological antagonist assay evaluating the contribution of these isoforms to the suppression of L-type Ca2+ current (ICaL). Patch-clamp electro-pharmacological studies revealed that the α2-agonist-induced suppression of ICaL involves mainly the α2C, to a lesser extent the α2B, and not the α2A isoforms. RT-qPCR evaluation revealed the presence of adra2b and adra2c (α2B and α2C isoform genes, respectively), but was unable to identify the expression of adra2a (α2A isoform gene) in the mouse left ventricle. Immunoblotting confirmed the presence only of the α2B and the α2C proteins in this tissue. The identified α2-AR isoform-linked regulation of ICaL in the mouse ventricle provides an important molecular substrate for the cardioprotective targeting.
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Affiliation(s)
- Edward V. Evdokimovskii
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, 142290 Pushchino, Russia; (E.V.E.); (O.Y.P.)
| | - Ryounghoon Jeon
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Mayo Clinic, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA; (R.J.); (S.P.)
| | - Sungjo Park
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Mayo Clinic, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA; (R.J.); (S.P.)
| | - Oleg Y. Pimenov
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, 142290 Pushchino, Russia; (E.V.E.); (O.Y.P.)
| | - Alexey E. Alekseev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Institutskaya 3, 142290 Pushchino, Russia; (E.V.E.); (O.Y.P.)
- Department of Cardiovascular Medicine, Center for Regenerative Medicine, Mayo Clinic, Stabile 5, Mayo Clinic, 200 1st Street SW, Rochester, MN 55905, USA; (R.J.); (S.P.)
- Correspondence: ; Tel.: +1-507-284-9501
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Mei B, Li J, Zuo Z. Dexmedetomidine attenuates sepsis-associated inflammation and encephalopathy via central α2A adrenoceptor. Brain Behav Immun 2021; 91:296-314. [PMID: 33039659 PMCID: PMC7749843 DOI: 10.1016/j.bbi.2020.10.008] [Citation(s) in RCA: 88] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 10/03/2020] [Accepted: 10/06/2020] [Indexed: 12/20/2022] Open
Abstract
Sepsis-associated encephalopathy (SAE) is a significant clinical issue that is associated with increased mortality and cost of health care. Dexmedetomidine, an α2 adrenoceptor agonist that is used to provide sedation, has been shown to induce neuroprotection under various conditions. This study was designed to determine whether dexmedetomidine protects against SAE and whether α2 adrenoceptor plays a role in this protection. Six- to eight-week old CD-1 male mice were subjected to cecal ligation and puncture (CLP). They were treated with intraperitoneal injection of dexmedetomidine in the presence or absence of α2 adrenoceptor antagonists, atipamezole or yohimbine, or an α2A adrenoceptor antagonist, BRL-44408. Hippocampus and blood were harvested for measuring cytokines. Mice were subjected to Barnes maze and fear conditioning 14 days after CLP to evaluate their learning and memory. CLP significantly increased the proinflammatory cytokines including tumor necrosis factor α, interleukin (IL)-6 and IL-1β in the blood and hippocampus. CLP also increased the permeability of blood-brain barrier (BBB) and impaired learning and memory. These CLP detrimental effects were attenuated by dexmedetomidine. Intracerebroventricular application of atipamezole, yohimbine or BRL-44408 blocked the protection of dexmedetomidine on the brain but not on the systemic inflammation. Astrocytes but not microglia expressed α2A adrenoceptors. Microglial depletion did not abolish the protective effects of dexmedetomidine. These results suggest that dexmedetomidine reduces systemic inflammation, neuroinflammation, injury of BBB and cognitive dysfunction in septic mice. The protective effects of dexmedetomidine on the brain may be mediated by α2A adrenoceptors in the astrocytes.
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Affiliation(s)
- Bin Mei
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22901, USA; Department of Anesthesiology, First Affiliated Hospital of Anhui Medical University, Hefei City, Anhui Province, PR China.
| | - Jun Li
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22901, USA.
| | - Zhiyi Zuo
- Department of Anesthesiology, University of Virginia, Charlottesville, VA 22901, USA.
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Tsentsevitsky A, Nurullin L, Tyapkina O, Bukharaeva E. Sympathomimetics regulate quantal acetylcholine release at neuromuscular junctions through various types of adrenoreceptors. Mol Cell Neurosci 2020; 108:103550. [PMID: 32890729 DOI: 10.1016/j.mcn.2020.103550] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/26/2020] [Accepted: 08/27/2020] [Indexed: 01/01/2023] Open
Abstract
The studies of the interaction between the sympathetic and motor nervous systems are extremely relevant due to therapy for many neurodegenerative and cardiovascular disorders involving adrenergic compounds. Evidences indicate close contact between sympathetic varicosities and neuromuscular synapses. This raises questions about the effects of catecholamines on synaptic transmission. The currently available information is contradictory, and the types of adrenoreceptors responsible for modulation of neurotransmitter release have not been identified in mammalian neuromuscular synapses. Our results have shown that the α1A, α1B, α2A, α2B, α2C, and β1 adrenoreceptor subtypes are expressed in mouse diaphragm muscle containing neuromuscular synapses and sympathetic varicosities. Pharmacological stimulation of adrenoreceptors affects both spontaneous and evoked acetylcholine quantal secretion. Agonists of the α1, α2 and β1 adrenoreceptors decrease spontaneous release. Activation of the α2 and β1 adrenoreceptors reduces the number of acetylcholine quanta released in response to a nerve stimulus (quantal content), but an agonist of the β2 receptors increases quantal content. Activation of α2 and β2 adrenoreceptors alters the kinetics of acetylcholine quantal release by desynchronizing the neurosecretory process. Specific blockers of these receptors eliminate the effects of the specific agonists. The action of blockers on quantal acetylcholine secretion indicates possible action of endogenous catecholamines on neuromuscular transmission. Elucidating the molecular mechanisms by which clinically utilized adrenomimetics and adrenoblockers regulate synaptic vesicle release at the motor axon terminal will lead to the creation of improved and safer sympathomimetics for the treatment of various neurodegenerative diseases with synaptic defects.
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Affiliation(s)
- Andrei Tsentsevitsky
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, PB 30, Kazan 420111, Russia
| | - Leniz Nurullin
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, PB 30, Kazan 420111, Russia
| | - Oksana Tyapkina
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, PB 30, Kazan 420111, Russia
| | - Ellya Bukharaeva
- Kazan Institute of Biochemistry and Biophysics FRC Kazan Scientific Center of RAS, PB 30, Kazan 420111, Russia.
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13
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Koyanagi Y, Torturo CL, Cook DC, Zhou Z, Hemmings HC. Role of specific presynaptic calcium channel subtypes in isoflurane inhibition of synaptic vesicle exocytosis in rat hippocampal neurones. Br J Anaesth 2019; 123:219-227. [PMID: 31056238 PMCID: PMC6676046 DOI: 10.1016/j.bja.2019.03.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/24/2019] [Accepted: 03/16/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND P/Q- and N-type voltage-gated calcium channels (VGCC) are the principal subtypes mediating synaptic vesicle (SV) exocytosis. Both the degree of isoflurane inhibition of SV exocytosis and VGCC subtype expression vary between brain regions and neurotransmitter phenotype. We hypothesised that differences in VGCC subtype expression contribute to synapse-selective presynaptic effects of isoflurane. METHODS We used quantitative live-cell imaging to measure exocytosis in cultured rat hippocampal neurones after transfection of the fluorescent biosensor vGlut1-pHluorin. Selective inhibitors of P/Q- and N-type VGCCs were used to isolate subtype-specific effects of isoflurane. RESULTS Inhibition of N-type channels by 1 μM ω-conotoxin GVIA reduced SV exocytosis to 81±5% of control (n=10). Residual exocytosis mediated by P/Q-type channels was further inhibited by isoflurane to 42±4% of control (n=10). The P/Q-type channel inhibitor ω-agatoxin IVA at 0.4 μM inhibited SV exocytosis to 29±3% of control (n=10). Residual exocytosis mediated by N-type channels was further inhibited by isoflurane to 17±3% of control (n=10). Analysis of isoflurane effects at the level of individual boutons revealed no difference in sensitivity to isoflurane between P/Q- or N-type channel-mediated SV exocytosis (P=0.35). There was no correlation between the effect of agatoxin (P=0.91) or conotoxin (P=0.15) and the effect of isoflurane on exocytosis. CONCLUSIONS Sensitivity of SV exocytosis to isoflurane in rat hippocampal neurones is independent of the specific VGCC subtype coupled to exocytosis. The differential sensitivity of VGCC subtypes to isoflurane does not explain the observed neurotransmitter-selective effects of isoflurane in hippocampus.
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Affiliation(s)
- Yuko Koyanagi
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Anesthesiology, Nihon University School of Dentistry, Tokyo, Japan
| | | | - Daniel C Cook
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Zhenyu Zhou
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA.
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14
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Huang C, Ng OTW, Chu JMT, Irwin MG, Hu X, Zhu S, Chang RCC, Wong GTC. Differential effects of propofol and dexmedetomidine on neuroinflammation induced by systemic endotoxin lipopolysaccharides in adult mice. Neurosci Lett 2019; 707:134309. [PMID: 31158431 DOI: 10.1016/j.neulet.2019.134309] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 05/13/2019] [Accepted: 05/30/2019] [Indexed: 01/01/2023]
Abstract
Propofol and dexmedetomidine are commonly used in clinical situations where neuroinflammation may be imminent or even established but comparative data on their effects on neuroinflammatory and cognitive parameters are lacking. Using a murine model of neuroinflammation induced by systemic lipopolysaccharide (LPS), this study compared the effects of these two agents on cognitive function, neuroinflammatory parameters, oxidative stress and neurotransmission. Male adult C57BL/6 N mice were anaesthetised with propofol or dexmedetomidine prior to intraperitoneal injection of LPS. Cognitive and motor function were assessed by the Y-maze and Rotarod tests respectively. Inflammatory responses were evaluated by relative levels of cytokine mRNA and immunoreactivity of glia cells. LPS caused a marked elevation in IL-1β and TNF-α levels both peripherally and in the brain, together with microglia activation (p < 0.05) and cognitive impairment. These changes were accompanied by an increase in 8-hydroxy-2'-deoxyguanosine (8-OHdG) (p < 0.05). Dexmedetomidine attenuated microglia activation (p < 0.05) and the elevation in 8-OHdG level (p < 0.05). Propofol did not affect cognition. However, both drugs lowered the number of vesicular glutamate transporter 1 (VGLUT 1), but was associated with higher levels of apoptosis and 8-OHdG (p < 0.05). Data from this study suggest dexmedetomidine and propofol have different anti-neuroinflammatory and neuroprotective profiles. However, neither drug can fully attenuate the effects of LPS induced cognitive impairment.
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Affiliation(s)
- Chunxia Huang
- Department of Anesthesiology, The Second Affiliated Hospital of Anhui Medical University, Hefei city, Anhui Province, PR China; Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Olivia Tsz-Wa Ng
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - John Man-Tak Chu
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Michael Garnet Irwin
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region
| | - Xianwen Hu
- Department of Anesthesiology, The Second Affiliated Hospital of Anhui Medical University, Hefei city, Anhui Province, PR China
| | - Shoufeng Zhu
- Department of Anesthesiology, The Second Affiliated Hospital of Anhui Medical University, Hefei city, Anhui Province, PR China
| | - Raymond Chuen-Chung Chang
- Laboratory of Neurodegenerative Diseases, School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region; State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, Hong Kong Special Administrative Region.
| | - Gordon Tin-Chun Wong
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region.
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15
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Wang Y, Wang C, Zhang D, Wang H, Bo L, Deng X. Dexmedetomidine Protects Against Traumatic Brain Injury-Induced Acute Lung Injury in Mice. Med Sci Monit 2018; 24:4961-4967. [PMID: 30013022 PMCID: PMC6067036 DOI: 10.12659/msm.908133] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Background Traumatic brain injury (TBI) leads to acute lung injury (ALI), in which the inflammatory response plays an important role in its pathophysiology. Recent studies suggest that dexmedetomidine (Dex) plays a protective role in acute inflammatory diseases. However, whether Dex has a protective effect on TBI-induced ALI is not clear. The aim of this study was to investigate the effect of Dex on TBI-induced ALI in mice. Material/Methods Mice were randomly divided into 5 groups: 1) sham group; 2) TBI group; 3) TBI+Dex group; 4) TBI+atipamezole (Atip) group; and 5) TBI+Dex+Atip group. Dex (50 μg/kg) was intraperitoneal injected immediately after TBI. The α2 adrenergic antagonist Atip (250 μg/kg) was intraperitoneal injected 15 minutes prior to Dex treatment. Then 24 hours later, the protein concentration in the bronchoalveolar lavage fluid (BALF), lung wet to dry weight ratio, hematoxylin and eosin (H&E) staining of lungs, the level of high-mobility group box protein 1(HMGB1) in serum, and the receptor for advanced glycation end products (RAGE) expression in lung were detected. Results Dex ameliorated the score of lung histological examination, as well as the severity of pulmonary edema and permeability. Moreover, Dex was observed to significantly suppress the expression of HMGBI and RAGE. However, the protective effects of Dex were partially reversed by the administration of Atip. Conclusions Dex may protect against TBI-induced ALI via the HMGB1-RAGE signal pathway, and this protective effect is partly dependent on its α2 adrenoceptor agonist action.
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Affiliation(s)
- Yuanyuan Wang
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, China (mainland).,Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China (mainland)
| | - Changli Wang
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, China (mainland)
| | - Dan Zhang
- Department of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, China (mainland).,Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China (mainland)
| | - Huihui Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China (mainland)
| | - Lulong Bo
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, China (mainland)
| | - Xiaoming Deng
- Faculty of Anesthesiology, Changhai Hospital, Naval Medical University, Shanghai, China (mainland).,Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, China (mainland)
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16
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Banks MI, Moran NS, Krause BM, Grady SM, Uhlrich DJ, Manning KA. Altered stimulus representation in rat auditory cortex is not causal for loss of consciousness under general anaesthesia. Br J Anaesth 2018; 121:605-615. [PMID: 30115259 DOI: 10.1016/j.bja.2018.05.054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/13/2018] [Accepted: 05/21/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Current concepts suggest that impaired representation of information in cortical networks contributes to loss of consciousness under anaesthesia. We tested this idea in rat auditory cortex using information theory analysis of multiunit responses recorded under three anaesthetic agents with different molecular targets: isoflurane, propofol, and dexmedetomidine. We reasoned that if changes in the representation of sensory stimuli are causal for loss of consciousness, they should occur regardless of the specific anaesthetic agent. METHODS Spiking responses were recorded with chronically implanted microwire arrays in response to acoustic stimuli incorporating varied temporal and spectral dynamics. Experiments consisted of four drug conditions: awake (pre-drug), sedation (i.e. intact righting reflex), loss of consciousness (a dose just sufficient to cause loss of righting reflex), and recovery. Measures of firing rate, spike timing, and mutual information were analysed as a function of drug condition. RESULTS All three drugs decreased spontaneous and evoked spiking activity and modulated spike timing. However, changes in mutual information were inconsistent with altered stimulus representation being causal for loss of consciousness. First, direction of change in mutual information was agent-specific, increasing under dexmedetomidine and decreasing under isoflurane and propofol. Second, mutual information did not decrease at the transition between sedation and LOC for any agent. Changes in mutual information under anaesthesia correlated strongly with changes in precision and reliability of spike timing, consistent with the importance of temporal stimulus features in driving auditory cortical activity. CONCLUSIONS The primary sensory cortex is not the locus for changes in representation of information causal for loss of consciousness under anaesthesia.
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Affiliation(s)
- M I Banks
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA.
| | - N S Moran
- Neuroscience Training Program, University of Wisconsin, Madison, WI, USA
| | - B M Krause
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - S M Grady
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
| | - D J Uhlrich
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | - K A Manning
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
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17
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Yu X, Franks NP, Wisden W. Sleep and Sedative States Induced by Targeting the Histamine and Noradrenergic Systems. Front Neural Circuits 2018; 12:4. [PMID: 29434539 PMCID: PMC5790777 DOI: 10.3389/fncir.2018.00004] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 01/11/2018] [Indexed: 01/07/2023] Open
Abstract
Sedatives target just a handful of receptors and ion channels. But we have no satisfying explanation for how activating these receptors produces sedation. In particular, do sedatives act at restricted brain locations and circuitries or more widely? Two prominent sedative drugs in clinical use are zolpidem, a GABAA receptor positive allosteric modulator, and dexmedetomidine (DEX), a selective α2 adrenergic receptor agonist. By targeting hypothalamic neuromodulatory systems both drugs induce a sleep-like state, but in different ways: zolpidem primarily reduces the latency to NREM sleep, and is a controlled substance taken by many people to help them sleep; DEX produces prominent slow wave activity in the electroencephalogram (EEG) resembling stage 2 NREM sleep, but with complications of hypothermia and lowered blood pressure—it is used for long term sedation in hospital intensive care units—under DEX-induced sedation patients are arousable and responsive, and this drug reduces the risk of delirium. DEX, and another α2 adrenergic agonist xylazine, are also widely used in veterinary clinics to sedate animals. Here we review how these two different classes of sedatives, zolpidem and dexmedetomideine, can selectively interact with some nodal points of the circuitry that promote wakefulness allowing the transition to NREM sleep. Zolpidem enhances GABAergic transmission onto histamine neurons in the hypothalamic tuberomammillary nucleus (TMN) to hasten the transition to NREM sleep, and DEX interacts with neurons in the preoptic hypothalamic area that induce sleep and body cooling. This knowledge may aid the design of more precise acting sedatives, and at the same time, reveal more about the natural sleep-wake circuitry.
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Affiliation(s)
- Xiao Yu
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - William Wisden
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
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18
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Melkonyan MM, Hunanyan L, Lourhmati A, Layer N, Beer-Hammer S, Yenkoyan K, Schwab M, Danielyan L. Neuroprotective, Neurogenic, and Amyloid Beta Reducing Effect of a Novel Alpha 2-Adrenoblocker, Mesedin, on Astroglia and Neuronal Progenitors upon Hypoxia and Glutamate Exposure. Int J Mol Sci 2017; 19:ijms19010009. [PMID: 29267189 PMCID: PMC5795961 DOI: 10.3390/ijms19010009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/17/2017] [Accepted: 12/19/2017] [Indexed: 12/17/2022] Open
Abstract
Locus coeruleus-noradrenergic system dysfunction is known to contribute to the progression of Alzheimer’s disease (AD). Besides a variety of reports showing the involvement of norepinephrine and its receptor systems in cognition, amyloid β (Aβ) metabolism, neuroinflammation, and neurogenesis, little is known about the contribution of the specific receptors to these actions. Here, we investigated the neurogenic and neuroprotective properties of a new α2 adrenoblocker, mesedin, in astroglial primary cultures (APC) from C57BL/6 and 3×Tg-AD mice. Our results demonstrate that mesedin rescues neuronal precursors and young neurons, and reduces the lactate dehydrogenase (LDH) release from astroglia under hypoxic and normoxic conditions. Mesedin also increased choline acetyltransferase, postsynaptic density marker 95 (PSD95), and Aβ-degrading enzyme neprilysin in the wild type APC, while in the 3×Tg-AD APC exposed to glutamate, it decreased the intracellular content of Aβ and enhanced the survival of synaptophysin-positive astroglia and neurons. These effects in APC can at least partially be attributed to the mesedin’s ability of increasing the expression of Interleukine(IL)-10, which is a potent anti-inflammatory, neuroprotective neurogenic, and Aβ metabolism enhancing factor. In summary, our data identify the neurogenic, neuroprotective, and anti-amyloidogenic action of mesedin in APC. Further in vivo studies are needed to estimate the therapeutic value of mesedin for AD.
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Affiliation(s)
- Magda M Melkonyan
- Department of Medical Chemistry, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Lilit Hunanyan
- Department of Medical Chemistry, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Ali Lourhmati
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Nikolas Layer
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Sandra Beer-Hammer
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology and ICePhA, University of Tuebingen, Wilhelmstr. 56, D-72076 Tübingen, Germany.
| | - Konstantin Yenkoyan
- Biochemistry Department, Yerevan state Medical University after M. Heratsi, 2 Koryun St., Yerevan 0025, Armenia.
| | - Matthias Schwab
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, University of Tübingen, Stuttgart, Auerbachstr. 112, D-70376 Stuttgart, Germany.
- Department of Pharmacy and Biochemistry, University of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
| | - Lusine Danielyan
- Department of Clinical Pharmacology, Institute of Clinical and Experimental Pharmacology and Toxicology, University Hospital of Tübingen, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
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19
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Chen L, Zhang B, Shan S, Zhao X. Neuroprotective effects of vitexin against isoflurane-induced neurotoxicity by targeting the TRPV1 and NR2B signaling pathways. Mol Med Rep 2016; 14:5607-5613. [PMID: 27878303 DOI: 10.3892/mmr.2016.5948] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 07/12/2016] [Indexed: 11/05/2022] Open
Abstract
Vitexin is a bioactive compound extracted from hawthorn leaves, which reduces blood pressure and has anti‑inflammatory and potential anticancer effects. However, the mechanisms underlying the protective effects of vitexin against isoflurane‑induced neurotoxicity remain elusive. Therefore, the aim of the present study was to investigate these mechanisms further. Sprague Dawley rats received 1.4% isoflurane in a 100% oxygen environment for 2 h. Human PC12 pheochromocytoma neurosecretory cells were exposed to 2% isoflurane for 12 h before they were treated with 1, 10 or 100 µM vitexin for a further 24 h. Vitexin inhibited the isoflurane-induced cell cytotoxicity and weakened isoflurane-induced neuroinflammation and oxidative stress pathways in PC12 cells. In addition, treatment with vitexin suppressed isoflurane‑induced caspase‑3 activation and increased β-secretase 1 levels in PC12 cells. Furthermore, vitexin treatment decreased the levels of isoflurane‑induced cytosolic calcium and reactive oxygen species, and downregulated the expression of transient receptor potential cation channel subfamily V member 1 (TRPV1) and glutamate ionotropic receptor NMDA type subunit 2B (NR2B) protein expression in isoflurane-treated PC12 cells. These results suggest that vitexin mediates its protective effects against isoflurane-induced neurotoxicity by targeting the TRPV1 and NR2B signaling pathways.
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Affiliation(s)
- Linlin Chen
- Department of Anesthesiology, The Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Bin Zhang
- Department of Anesthesiology, The Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Shiqiang Shan
- Department of Anesthesiology, The Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
| | - Xin Zhao
- Department of Anesthesiology, The Cangzhou Central Hospital, Cangzhou, Hebei 061000, P.R. China
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