Muscarinic receptors depress gabaergic synaptic transmission in rat midbrain dopamine neurons

被引:50
作者
Grillner, P
Berretta, N
Bernardi, G
Svensson, TH
Mercuri, NB
机构
[1] IRCCS, Clin S Lucia, I-00179 Rome, Italy
[2] Karolinska Inst, Div Neuropsychopharmacol, Dept Physiol & Pharmacol, S-17177 Stockholm, Sweden
[3] Univ Roma Tor Vergata, I-00173 Rome, Italy
关键词
acetylcholine; muscarine; nicotine; inhibitory postsynaptic potentials; miniature inhibitory postsynaptic currents; presynaptic inhibition;
D O I
10.1016/S0306-4522(99)00579-5
中图分类号
Q189 [神经科学];
学科分类号
071006 ;
摘要
The effects of muscarine and nicotine on evoked and spontaneous release of GABA were studied using intracellular and whole-cell patch-clamp recordings from rat midbrain dopamine neurons in an in vitro slice preparation. Muscarine (30 mu M) reversibly depressed the pharmacologically isolated inhibitory postsynaptic potential evoked by local electrical stimulation. The maximal inhibition of the inhibitory postsynaptic potential amplitude was 39.6 +/- 5%. This depressant effect of muscarine was blocked by the M3/M1 receptor antagonist 3-diphenylacetoxy-N-methylpiperidine methiodide (100 nM), but was slightly affected by the M1/M3 receptor antagonist pirenzepine (1 mu M). In addition, muscarine decreased the frequency of the miniature synaptic currents without any effect on their amplitude. Moreover, muscarine did not change the GABA-induced hyperpolarization, indicating that its effect on the inhibitory postsynaptic potential is mediated by presynaptic receptors. On the contrary, the cholinergic agonist nicotine did not change the frequency or the amplitude of the spontaneous glutamatergic and GABAergic synaptic currents. Our data indicate that a prevalent activation of presynaptic M3 muscarinic receptors inhibits the GABA-mediated synaptic events, while the activation of nicotinic receptors does not affect the release of glutamate and GABA on midbrain dopamine neurons. (C) 2000 IBRO. Published by Elsevier Science Ltd.
引用
收藏
页码:299 / 307
页数:9
相关论文
共 45 条