1. Academic Validation
  2. CGP 36216 is a selective antagonist at GABA(B) presynaptic receptors in rat brain

CGP 36216 is a selective antagonist at GABA(B) presynaptic receptors in rat brain

  • Eur J Pharmacol. 2001 Mar;415(2-3):191-5. doi: 10.1016/s0014-2999(01)00842-1.
J Ong 1 S Bexis V Marino D A Parker D I Kerr W Froestl
Affiliations

Affiliation

  • 1 Department of Anaesthesia and Intensive Care, The University of Adelaide, South Australia 5005, Adelaide, Australia. jennifer.ong@adelaide.edu.au
Abstract

In rat neocortical preparations maintained in Mg(2+)-free Krebs medium, baclofen depressed the frequency of spontaneous discharges in a concentration-dependent manner (EC(50) = 6 microM), sensitive to (3-aminopropyl)ethylphosphinic acid (CGP 36216) (100, 300 and 500 microM) (pA(2) = 3.9 +/- 0.1). By contrast, CGP 36216, up to 1 mM, was ineffective in antagonising baclofen-induced hyperpolarisations, mediated through gamma-aminobutyric acid(B) (GABA(B)) postsynaptic receptors. In electrically stimulated brain slices preloaded with [3H]GABA, CGP 36216 increased [3H]GABA release (IC(50) = 43 microM), which was reversed by baclofen (20 microM). While CGP 36216 is ineffective at GABA(B) postsynaptic receptors, it is appreciably more active at presynaptic receptors.

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