info:eu-repo/semantics/article
Muscarinic inhibition of hippocampal and striatal adenylyl cyclase is mainly due to the m4 receptor
Fecha
2009-08Registro en:
Sánchez, Gonzalo Manuel; Colettis, Natalia Claudia; Vazquez, Pablo; Cerveñansky, Carlos; Aguirre, Alejandra Inés; et al.; Muscarinic inhibition of hippocampal and striatal adenylyl cyclase is mainly due to the m4 receptor; Springer/Plenum Publishers; Neurochemical Research; 34; 8; 8-2009; 1363-1371
0364-3190
CONICET Digital
CONICET
Autor
Sánchez, Gonzalo Manuel
Colettis, Natalia Claudia
Vazquez, Pablo
Cerveñansky, Carlos
Aguirre, Alejandra Inés
Quillfeldt, Jorge A.
Jerusalinsky, Diana Alicia
Kornisiuk, Edgar Ernesto
Resumen
The five muscarinic acetylcholine receptors (M(1)-M(5)) are differentially expressed in the brain. M(2) and M(4) are coupled to inhibition of stimulated adenylyl cyclase, while M(1), M(3) and M(5) are mainly coupled to the phosphoinositide pathway. We studied the muscarinic receptor regulation of adenylyl cyclase activity in the rat hippocampus, compared to the striatum and amygdala. Basal and forskolin-stimulated adenylyl cyclase activity was higher in the striatum but the muscarinic inhibition was much lower. Highly selective muscarinic toxins MT1 and MT2-affinity order M(1) > or = M(4) >> others-and MT3-highly selective M(4) antagonist-did not show significant effects on basal or forskolin-stimulated cyclic AMP production but, like scopolamine, counteracted oxotremorine inhibition. Since MTs have negligible affinity for M(2), M(4) would be the main subtype responsible for muscarinic inhibition of forskolin-stimulated enzyme. Dopamine stimulated a small fraction of the enzyme (3.1% in striatum, 1.3% in the hippocampus). Since MT3 fully blocked muscarinic inhibition of dopamine-stimulated enzyme, M(4) receptor would be responsible for this regulation.