[Effect of GABA-ergic substances on the analgesic effect of morphine in rats].

The effect of GABA-ergic compounds on morphine-induced analgesia was studied to reveal probable interaction of GABA and opiates. As an index for morphine effect the reaction of vocalization in response to electrical stimulation of the rat tail was used. It was shown that thiosemicarbazide, the inhibitor of glutamate decarboxylase and bicuculline, GABA-ergic receptor blocking agent, which were proposed to be joined in a group of GABA-negative compounds, reduce and shorten the effect of morphine. Depakine, the inhibitor of alpha-ketoglutarate-GABA-transaminase, as well as GABA itself administered in high doses (GABA-positive actions) make morphine analgesia more pronounced and longer. Probable causes of the described interrelationship between GABA and opiates are discussed.