ISSN:
1432-1912
Keywords:
Serotonin autoreceptors
;
Rat hippocampus
;
5-HT receptor subtypes
;
Serotonin release
;
Superfused synaptosomes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The 5-hydroxytryptamine (5-HT) autoreceptors mediating inhibition of [3H]5-HT release in rat hippocampus have been characterized pharmacologically in terms of 5-HT receptor subtype by using superfused synaptosomes depolarized with 15 mM KCl. Exogenous 5-HT inhibited in a concentration-dependent way (pEC30=8.74) the K+-evoked release of [3H]5-HT. Methiothepin shifted the concentration-response curve of 5-HT to the right (pA2=8.62). The 5-HT2 receptor antagonists, ketanserin, methysergide or spiperone were ineffective against 5-HT. The 5-HT1 receptor agonist, 5-methoxy-3-[1,2,3,6-tetra-hydropyridin-4-yl]-1H-indole (RU 24969) mimicked 5-HT and was equipotent as an inhibitor of the release of [3H]5-HT. In contrast, the putative 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) was almost ineffective at 1 μM. Finally, (−)propranolol, used as a non-selective 5-HT1A/5-HT1B receptor antagonist, shifted to the right (pA2=7.91) the concentration-response curve of 5-HT whereas the 5-HT1C receptor antagonist mesulergine was ineffective. In conclusion, 5-HT nerve terminals of rat hippocampus possess autoreceptors which appear to belong to the 5-HT1B subtype.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00569364
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