title: Type A and B gaba receptors mediate inhibition of acetylcholine release from cholinergic nerve terminals in the superior cervical ganglion of rat.
abstract: The effects of ?-amino-n-butyric acid (GABA), (+)bicuculline, isoguvacine and 3-(4-chlorophenyl)-4-aminobutyrate [(+/-)baclofen] on the K-induced release of [(3)H]acetylcholine (ACh) were studied in the superior cervical ganglia of the rat in vitro. GABA and isoguvacine inhibited [(3)H]ACh release and these inhibitions were reversible by (+)bicuculline. Furthermore, the release of [(3)H]ACh was also inhibited by (+/-)baclofen. In receptor-binding studies, binding of [(3)H]GABA to membrane preparations from the superior cervical ganglia was inhibited by both (+/-)baclofen and (+)bicuculline. It is concluded that the inhibitory effect of GABA on the release of ACh can be mediated by GABA(A)(bicuculline-sensitive) and by GABA(B) (baclofen-activated) receptors. Our findings are compatible with the existence of a non-synaptic GABAergic inhibitory system involving GABA(A) and GABA(B) receptors on cholinergic nerve terminals in the superior cervical ganglion of rat.
authors.affiliation: Central Research Laboratory, Medical University, Szeged, Hungary.
authors.forename: Z
authors.initials: Z
authors.lastname: Farkas
authors.forename: P
authors.initials: P
authors.lastname: Kása
authors.forename: V J
authors.initials: VJ
authors.lastname: Balcar
authors.forename: F
authors.initials: F
authors.lastname: Joó
authors.forename: J R
authors.initials: JR
authors.lastname: Wolff