[Effect of adrenoblockers on the analgesic effect of GABA-positive preparations]

The experiments on rats have shown that selective alpha 1 and alpha 2 adrenoceptor blockers (prazosin and yohimbine) and an inhibitor of dopamine-beta-hydrolase FD-008 failed to change the antinociceptive effect of baclofen, a direct GABAB receptor agonist. The antinociceptive effect of THIP and depakin, acting predominantly on GABAA receptors, was significantly reduced by prazosin, FD-008 and yohimbine in vocalization test. In tail-flick test the analgetic effect of THIP and depakin was not altered by prazosin and FD-008, but was increased by yohimbine. The role of adrenergic mechanisms in GABAA and GABAB receptor-mediated analgesia is discussed.