N-ethylmaleimide selectively blocks presynaptic GABA-B autoreceptor but not heteroreceptor-mediated inhibition in adult rat striatal slices.
Intracellular recording techniques were used in slices of adult rat striatum to compare the sensitivity of presynaptic gamma-aminobutyric acid type B (GABA-B) autoreceptor and heteroreceptor-mediated inhibition to the sulfhydryl alkylating agent, N-ethylmaleimide (NEM). NEM (100 microM) alone had no significant effect on resting potential or input resistance and did not consistently effect stimulus-evoked responses. Treatment of slices with NEM for up to 1 h, either in the presence or the absence of the GABA-B receptor-specific agonist, baclofen (BAC; 100 microM), completely blocked the BAC-induced depression of inhibitory, but not excitatory, postsynaptic potentials. This differential sensitivity to NEM alkylation suggests that in the adult rat striatum, the presynaptic GABA-B autoreceptors and heteroreceptors may exhibit distinct receptor-effector coupling mechanisms.
Phelan
K D
KD
Department of Anatomy/Slot 510, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA. phelankevind@exchange.uams.edu
D000818:Animals; D017660:Autoreceptors / Q000037:antagonists & inhibitors* / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects* / Q000502:physiology; D005033:Ethylmaleimide / Q000494:pharmacology*; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018080:Receptors, GABA-B / Q000187:drug effects* / Q000502:physiology; D013439:Sulfhydryl Reagents / Q000494:pharmacology*; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D017660:Autoreceptors; D018080:Receptors, GABA-B; D013439:Sulfhydryl Reagents; D005033:Ethylmaleimide