Serotonin (5-HT) Receptor Subtypes Mediate Regulation of Neuromodulin Secretion in Rat Hypothalamic Neurons.
- Author:
Chur CHIN
1
;
Seong Il KIM
Author Information
1. Nano-Science Research Division, Korea Institute of Science & Technology, Seoul 136-791, Korea. s-ikim@kist.re.kr
- Publication Type:Original Article
- Keywords:
neuromodulin signaling;
selective serotonin agonists;
rat hypothalamus;
cAMP;
intracellular Ca2+
- MeSH:
Animals;
Calcium;
GAP-43 Protein*;
GTP-Binding Proteins;
Inositol;
Neurons*;
Rats*;
Receptor, Serotonin, 5-HT1A;
Receptor, Serotonin, 5-HT2C;
Receptors, Serotonin, 5-HT4;
RNA, Messenger;
Sarcoplasmic Reticulum;
Serotonin*;
Adenylyl Cyclases
- From:Genomics & Informatics
2007;5(2):77-82
- CountryRepublic of Korea
- Language:English
-
Abstract:
Serotonin (5-HT), the endogenous nonselective 5-HT receptor agonist, activates the inositol -1,4,5- triphosphate / calcium (InsP3/Ca2+) signaling pathway and exerts both stimulatory and inhibitory actions on cAMP production and neuromodulin secretion in rat hypothalamic neurons. Specific mRNA transcripts for 5-HT1A, 5-HT2C and 5-HT4 were identified in rat hypothalamic neurons. These experiments were supported by combined techniques such as cAMP and a Ca2+ assays in order to elucidate the associated receptors and signaling pathways. The cAMP production and neuromodulin release were profoundly inhibited during the activation of the Gi-coupled 5-HT1A receptor. Treatment with a selective agonist to activate the Gq-coupled 5-HT2C receptor stimulated InsP3 production and caused Ca2+ release from the sarcoplasmic reticulum. Selective activation of the Gs-coupled 5-HT4 receptor also stimulated cAMP production, and caused an increase in neuromodulin secretion. These findings demonstrate the ability of 5-HT receptor subtypes expressed in neurons to induce neuromodulin production. This leads to the activation of single or multiple G-proteins which regulate the InsP3/Ca2+/PLC-gamma and adenyl cyclase / cAMP signaling pathways.
