Document Detail

Inhibition by 5-HT7 receptor stimulation of GABAA receptor-activated current in cultured rat suprachiasmatic neurones.
MedLine Citation:
PMID:  7965836     Owner:  NLM     Status:  MEDLINE    
1. Whole-cell voltage-clamp recordings were made from postnatal rat suprachiasmatic (SCN) neurones to investigate possible modulation by 5-hydroxytryptamine (5-HT) of gamma-aminobutyric acid (GABA)-activated current (IGABA). 2. 5-HT reversibly inhibited IGABA in a concentration-dependent manner (10(-10) to 10(-6) M). (+/-)-8-Hydroxy-2-N,N-dipropylaminotetralin (8-OH-DPAT, 10(-10) to 10(-5) M) and 5-carboxamidotryptamine (10(-6) M) also inhibited IGABA, whereas 1-(2,5-dimethyl-4-iodophenyl)-2-aminopropane (DOI, 10(-6) M) had no significant effect. 3. The effect of 8-OH-DPAT (10(-7) M) was blocked by ritanserin (10(-7) M), but not by pindolol (10(-7) M). The effect of 5-HT was also suppressed by ritanserin, but not by pindolol, ketanserin (10(-7) M) or ICS 205-930 (10(-6) M). 4. 8-Bromo-cAMP (10(-3) M) or forskolin (5 x 10(-5) M) suppressed IGABA. The effects of forskolin and 5-HT were not additive. Furthermore, the effect of 5-HT (10(-7) M) was significantly reduced by N-[2-(methylamino)ethyl]-5-isoquinoline sulphonamide (H-8, 10(-6) M). 5. It is concluded that 5-HT inhibits IGABA in the SCN neurones, which involves the activation of 5-HT7 receptors and cAMP-coupled systems.
F Kawahara; H Saito; H Katsuki
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  478 ( Pt 1)     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  1994 Jul 
Date Detail:
Created Date:  1994-12-08     Completed Date:  1994-12-08     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  67-73     Citation Subset:  IM    
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
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MeSH Terms
8-Hydroxy-2-(di-n-propylamino)tetralin / pharmacology
Cell Membrane / drug effects,  physiology
Cells, Cultured
Cyclic AMP / physiology
Dose-Response Relationship, Drug
Forskolin / pharmacology
Membrane Potentials / drug effects
Neurons / drug effects,  physiology*
Rats, Wistar
Receptors, GABA-A / drug effects,  physiology*
Receptors, Serotonin / drug effects,  physiology*
Ritanserin / pharmacology
Serotonin / pharmacology*
Suprachiasmatic Nucleus / physiology*
gamma-Aminobutyric Acid / pharmacology*
Reg. No./Substance:
0/Receptors, GABA-A; 0/Receptors, Serotonin; 50-67-9/Serotonin; 56-12-2/gamma-Aminobutyric Acid; 60-92-4/Cyclic AMP; 66428-89-5/Forskolin; 78950-78-4/8-Hydroxy-2-(di-n-propylamino)tetralin; 87051-43-2/Ritanserin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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