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The medial preoptic area (MPOA) of the hypothalamus is critically involved in the regulation of male sexual behavior and has been implicated in several homeostatic processes. Serotonin (5-hydroxytryptamine, 5-HT) inhibits sexual behavior via effects in the MPOA, where there are high densities of 5-HT(1A) and 5-HT(1B) receptor subtypes. We used whole-cell recordings under voltage-clamp conditions to investigate the serotonergic modulation of gamma-aminobutyric acid (GABA)ergic and glutamatergic synaptic transmission in mechanically dissociated rat MPOA neurons with native presynaptic nerve endings. Spontaneous GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in the MPOA were completely blocked by bicuculline. Serotonin reversibly reduced the GABAergic mIPSC frequency without affecting the mean current amplitude. Serotonergic inhibition of mIPSC frequency was mimicked by (+/-)-8-hydroxy-2-dipropylaminotetralin hydrobromide, a specific 5-HT(1A) receptor agonist, and blocked by 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide, a specific 5-HT(1A) receptor antagonist. 6-Cyano-7-nitroquinoxaline-2,3-dione completely blocked spontaneous glutamatergic miniature excitatory postsynaptic currents (mEPSCs) in the MPOA. Serotonin reversibly decreased the glutamatergic mEPSC frequency without affecting the mean current amplitude. Serotonergic inhibition of mEPSC frequency was mimicked by CGS 12066B, a specific 5-HT(1B) receptor agonist, and blocked by SB 216641, a specific 5-HT(1B) receptor antagonist. Stimulation of adenylyl cyclase with forskolin increased the frequencies of GABAergic mIPSCs and glutamatergic mEPSCs, and blocked the inhibitory effects of 5-HT. H-89, a selective protein kinase A (PKA) inhibitor, decreased the frequencies of GABAergic mIPSCs and glutamatergic mEPSCs, and blocked their reduction by 5-HT. These findings suggest that 5-HT reduces the frequency of GABAergic mIPSCs and glutamatergic mEPSCs through 5-HT(1A) and 5-HT(1B) receptor-mediated inhibition, respectively, of the PKA-dependent pathway in the presynaptic nerve terminals of MPOA neurons.
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http://dx.doi.org/10.1038/sj.npp.1301396 | DOI Listing |
bioRxiv
August 2025
Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90025-7239, USA.
Unlabelled: Serotonin (5-HT) is a hormonal messenger that confers state-level changes upon the nervous system in both humans and flies. In , lobula columnar (LC) cells are feature-detecting neurons that project from the optic lobe to the central brain, where each population forms an anatomically-distinct glomerulus with heterogeneous synaptic partners. Here, we investigated serotonin's effect on two LC populations with different 5-HT receptor expression profiles.
View Article and Find Full Text PDFNat Commun
August 2025
Department of Pharmacology and Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA.
Through its widespread reciprocal connections with the cerebral cortex, the claustrum is implicated in sleep and waking cortical network states. Yet, basic knowledge of neuromodulation in this structure is lacking. The claustrum is richly innervated by serotonergic fibers, expresses serotonin receptors, and is suggested to play a role in the ability of psilocybin, which is metabolized to the non-specific serotonin receptor agonist psilocin, to disrupt cortex-wide network states.
View Article and Find Full Text PDFJ Neurophysiol
August 2025
Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA 90025-7239, USA.
Serotonin (5-HT) is a hormonal messenger that confers state-level changes upon the nervous system in both humans and flies. In , lobula columnar (LC) cells are feature-detecting neurons that project from the optic lobe to the central brain, where each population forms an anatomically distinct glomerulus with heterogeneous synaptic partners. Here, we investigated serotonin's effect on two LC populations with different 5-HT receptor expression profiles.
View Article and Find Full Text PDFCephalalgia
July 2025
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan.
BackgroundThe antimigraine drug sumatriptan causes adverse chest effects, namely dyspnea and chest tightness, through unclear mechanisms. Dyspnea is an unpleasant sensation evoked by peripheral sensory signals transmitted to the central nervous system. Capsaicin-sensitive lung vagal (CSLV) afferents are nociceptive-like fibers that provide sensory input from the airways and lungs, mediating airway defense reflexes and evoking unpleasant respiratory sensations.
View Article and Find Full Text PDFKorean J Physiol Pharmacol
September 2025
Department of Physiology, Institute of Bioscience and Biotechnology, Kangwon National University College of Medicine, Chuncheon 24341, Korea.
Alprenolol is a nonselective β-adrenoceptor antagonist used in treating cardiovascular diseases by stabilizing elevated heart rates and myocardial contractility through the inhibition of sympathetic nerve transmissions alongside its role as an antagonist of 5-HT and 5-HT receptors. This study aimed to examine whether alprenolol can affect human Kv1.3 channel (hKv1.
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