Consolo_1996_J.Pharmacol.Exp.Ther_277_823

Reference

Title : Endogenous serotonin facilitates in vivo acetylcholine release in rat frontal cortex through 5-HT 1B receptors - Consolo_1996_J.Pharmacol.Exp.Ther_277_823
Author(s) : Consolo S , Arnaboldi S , Ramponi S , Nannini L , Ladinsky H , Baldi G
Ref : Journal of Pharmacology & Experimental Therapeutics , 277 :823 , 1996
Abstract :

We characterized the role of endogenous serotonin (5-HT) in regulating in vivo acetylcholine (ACh) output in frontal cortex of freely moving rats using the microdialysis technique. Systemic (0.63, 1.25 and 2.5 mg/kg, i.p.) or local (20 and 40 microM, reverse dialysis) administration of the 5-HT releaser and uptake inhibitor, d-norfenfluramine, dose-dependently enhanced frontal cortex ACh output. The d-norfenfluramine-induced increase in cortical ACh release was tetrodotoxin sensitive and completely prevented by a 7-day chemical degeneration of the serotonergic afferents to the frontal cortex. Investigating the 5-HT receptors that might mediate the d-norfenfluramine cholinergic effect, we found that the 5-HT4 (GR 125487) and 5-HT2A/2C (ritanserin) receptor antagonists, at doses effective in other in vivo tests, did not prevent the increase in cortical ACh output induced by the maximal effective does of d-norfenfluramine. However, the 5-HT1A/1B receptor antagonists (-)-pindolol (8 mg/kg, s.c.) or (-)-propanolol (8.8 mg/kg, i.p.) antagonized the increasing effect of d-norfenfluramine although the selective 5-HT1A receptor antagonist WAY-100635 (1 and 2 mg/kg, s.c.) did not. In accordance with an involvement of the 5-HT1B receptor in the ACh facilitation induced by d-norfenfluramine is the finding that the selective 5-HT1B agonist, CP-93,129, given locally (2, 4 and 8 micrograms/side) does-dependently raised cortical ACh release. In conclusion, the overall regulatory control exerted by endogenous 5-HT in vivo is to facilitate frontal cortex ACh release through 5-HT1B receptors located in the frontal cortex. The 5-HT1B receptors may act indirectly to facilitate ACh release probably by inhibiting cortical inhibitory inputs onto the cholinergic neurons.

PubMedSearch : Consolo_1996_J.Pharmacol.Exp.Ther_277_823
PubMedID: 8627564

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Citations formats

Consolo S, Arnaboldi S, Ramponi S, Nannini L, Ladinsky H, Baldi G (1996)
Endogenous serotonin facilitates in vivo acetylcholine release in rat frontal cortex through 5-HT 1B receptors
Journal of Pharmacology & Experimental Therapeutics 277 :823

Consolo S, Arnaboldi S, Ramponi S, Nannini L, Ladinsky H, Baldi G (1996)
Journal of Pharmacology & Experimental Therapeutics 277 :823