The pharmacological profile of GABA receptors on cultured insect neurones

Neuronal cultures of the cockroach, Periplaneta americana, were used to stu dy the pharmacological profile of GABA receptors using the whole-cell-volta ge clamp technique. The results indicated that insect GABA receptors are li nked to a chloride channel that can be activated by both GABA(A) and GABA(C ) receptor agonists. The receptors are blocked by GABA(A) chloride channel blockers and some insecticides but not by competitive GABA(A) receptor anta gonists. The GABA(C) receptor competitive antagonists were either full or p artial agonists of the cockroach GABA receptors. The receptors were modulat ed by the enantiomers of lindane. In conclusion, insect GABA receptors appe ar to have a distinct pharmacological profile that does not conform to eith er vertebrate GABA(A) or GABA(C) receptors. (C) 1999 Elsevier Science Ltd. All rights reserved.