Regulation of muscarinic acetylcholine receptor-mediated synaptic responses by GABA(B) receptors in the rat hippocampus. Export

@article{citeulike:1076288, abstract = {1. Both GABA(B) and muscarinic acetylcholine receptors (mAChRs) influence hippocampal-dependent mnemonic processing. Here the possibility of a direct interaction between GABA(B) receptors and mAChR-mediated synaptic responses has been studied using intracellular recording in rat hippocampal slices. 2. The GABA(B) receptor agonist (-)-baclofen (5-10 microM) depressed an atropine-sensitive slow EPSP (EPSP(M)) and occluded the GABA(B)-receptor-mediated IPSP (IPSP(B)) which preceded it. These inhibitory effects were accompanied by postsynaptic hyperpolarization (9 +/- 2 mV) and a reduction in cell input resistance (12 +/- 3 \%). 3. The selective GABA(B) receptor antagonist CGP 55845A (1 microM) fully reversed the depressant effects of (-)-baclofen (5-10 microM) such that in the combined presence of (-)-baclofen and CGP 55845A the EPSP(M) was 134 +/- 21 \% of control. 4. (-)-Baclofen (5-10 microM) caused a small (28 +/- 11 \%) inhibition of carbachol-induced (3.0 microM) postsynaptic depolarizations and increases in input resistance. 5. CGP 55845A (1 microM) alone caused an increase in the amplitude of the EPSP(M) (253 +/- 74 \% of control) and blocked the IPSP(B) that preceded it. 6. In contrast, the selective GABA uptake inhibitor NNC 05-0711 (10 microM) increased the amplitude of the IPSP(B) by 141 +/- 38 \% and depressed the amplitude of the EPSP(M) by 58 +/- 10 \%. This inhibition was abolished by CGP 55845A (1 microM). 7. Taken together these data provide good evidence that synaptically released GABA activates GABA(B) receptors that inhibit mAChR-mediated EPSPs in hippocampal CA1 pyramidal neurones. The mechanism of inhibition may involve both pre- and postsynaptic elements.}, address = {MRC Centre for Synaptic Plasticity, University of Bristol, University Walk, Bristol BS8 1TD, UK.}, author = {Morton, R. A. and Manuel, N. A. and Bulters, D. O. and Cobb, S. R. and Davies, C. H.}, citeulike-article-id = {1076288}, citeulike-linkout-0 = {http://view.ncbi.nlm.nih.gov/pubmed/11559773}, citeulike-linkout-1 = {http://www.hubmed.org/display.cgi?uids=11559773}, day = {15}, issn = {0022-3751}, journal = {J Physiol}, keywords = {acetylcholine, gabab, hippocampe, muscarinique}, month = {September}, number = {Pt 3}, pages = {757--766}, posted-at = {2007-01-30 13:41:12}, priority = {2}, title = {Regulation of muscarinic acetylcholine receptor-mediated synaptic responses by GABA(B) receptors in the rat hippocampus.}, url = {http://view.ncbi.nlm.nih.gov/pubmed/11559773}, volume = {535}, year = {2001} }

TY - JOUR ID - citeulike:1076288 L3 - citeulike-article-id:1076288 N2 - 1. Both GABA(B) and muscarinic acetylcholine receptors (mAChRs) influence hippocampal-dependent mnemonic processing. Here the possibility of a direct interaction between GABA(B) receptors and mAChR-mediated synaptic responses has been studied using intracellular recording in rat hippocampal slices. 2. The GABA(B) receptor agonist (-)-baclofen (5-10 microM) depressed an atropine-sensitive slow EPSP (EPSP(M)) and occluded the GABA(B)-receptor-mediated IPSP (IPSP(B)) which preceded it. These inhibitory effects were accompanied by postsynaptic hyperpolarization (9 +/- 2 mV) and a reduction in cell input resistance (12 +/- 3 %). 3. The selective GABA(B) receptor antagonist CGP 55845A (1 microM) fully reversed the depressant effects of (-)-baclofen (5-10 microM) such that in the combined presence of (-)-baclofen and CGP 55845A the EPSP(M) was 134 +/- 21 % of control. 4. (-)-Baclofen (5-10 microM) caused a small (28 +/- 11 %) inhibition of carbachol-induced (3.0 microM) postsynaptic depolarizations and increases in input resistance. 5. CGP 55845A (1 microM) alone caused an increase in the amplitude of the EPSP(M) (253 +/- 74 % of control) and blocked the IPSP(B) that preceded it. 6. In contrast, the selective GABA uptake inhibitor NNC 05-0711 (10 microM) increased the amplitude of the IPSP(B) by 141 +/- 38 % and depressed the amplitude of the EPSP(M) by 58 +/- 10 %. This inhibition was abolished by CGP 55845A (1 microM). 7. Taken together these data provide good evidence that synaptically released GABA activates GABA(B) receptors that inhibit mAChR-mediated EPSPs in hippocampal CA1 pyramidal neurones. The mechanism of inhibition may involve both pre- and postsynaptic elements. IS - Pt 3 JF - J Physiol SN - 0022-3751 AD - MRC Centre for Synaptic Plasticity, University of Bristol, University Walk, Bristol BS8 1TD, UK. EP - 766 TI - Regulation of muscarinic acetylcholine receptor-mediated synaptic responses by GABA(B) receptors in the rat hippocampus. VL - 535 SP - 757 KW - acetylcholine KW - gabab KW - hippocampe KW - muscarinique AU - Morton, RA AU - Manuel, NA AU - Bulters, DO AU - Cobb, SR AU - Davies, CH PY - 2001/09/15/ UR - http://view.ncbi.nlm.nih.gov/pubmed/11559773 ER -