| First Author | McClure-Begley TD | Year | 2014 |
| Journal | Biochem Pharmacol | Volume | 91 |
| Issue | 1 | Pages | 87-96 |
| PubMed ID | 24953818 | Mgi Jnum | J:215485 |
| Mgi Id | MGI:5605438 | Doi | 10.1016/j.bcp.2014.06.010 |
| Citation | McClure-Begley TD, et al. (2014) Presynaptic GABAB autoreceptor regulation of nicotinic acetylcholine receptor mediated [(3)H]-GABA release from mouse synaptosomes. Biochem Pharmacol 91(1):87-96 |
| abstractText | Activation of nicotinic acetylcholine receptors (nAChRs) can elicit neurotransmitter release from presynaptic nerve terminals. Mechanisms contributing to cell-and-terminal specific regulation of nAChR-mediated neurotransmitter exocytosis are not fully understood. The experiments discussed here examine how activation of GABAB auto- and hetero-receptors suppress nAChR-mediated release of [(3)H]-GABA and [(3)H]-dopamine ((3)H-DA) from mouse striatal synaptosomes. Activation of presynaptic GABAB receptors with (R)-baclofen decreased both [(3)H]-GABA and [(3)H]-DA release evoked by potassium depolarization. However, when nAChRs were activated with ACh to evoke neurotransmitter release, (R)-baclofen had no effect on [(3)H]-DA release, but potently inhibited ACh-evoked [(3)H]-GABA release. Inhibition of nAChR-evoked [(3)H]-GABA release by (R)-baclofen was time sensitive and the effect was lost after prolonged exposure to the GABAB agonist. The early inhibitory effect of GABAB activation on ACh-evoked [(3)H]-GABA release was partially attenuated by antagonists of the phosphatase, calcineurin. Furthermore, antagonists of protein kinase C (PKC) prevented the time-dependent loss of the inhibitory (R)-baclofen effect on [(3)H]-GABA release. These results suggest that alpha4beta2*-nAChRs present on GABAergic nerve terminals in the striatum are subject to functional regulation by GABAB autoreceptors that is apparently cell-type specific, since it is absent from DAergic striatal nerve terminals. In addition, the functional modulation of alpha4beta2*-type nAChRs on striatal GABAergic nerve terminals by GABAB autoreceptor activation is time-sensitive and appears to involve opposing actions of calcineurin and PKC. |
