Behavioral aspects of GABAergic-dopaminergic interactions in the central nervous system.

GABAergic-dopaminergic relationships in rats were analysed quantitatively by means of behavioral studies. Acute and long-term haloperidol administration induced significant leftward displacement of the control dose-response curves for picrotoxin but not those for strychnine or 3-mercaptopropionic acid (3-MPA). Apomorphine given acutely increased the sensitivity of the animal to strychnine but not to picrotoxin or 3-MPA. In animals that presented convulsion a stereotyped gnawing and/or licking behavior was observed immediately after the ictus activity as a consequence of the combined acute administration of haloperidol and picrotoxin. Long-term haloperidol treatment increased the gnawing and/or licking behavior immediately before and/or after the ictus activity induced by picrotoxin (1 and 72 h after haloperidol withdrawal) or 3-MPA (72 h after withdrawal). A possible effect of the drugs employed on the DA-nigroamygdaloid and/or the GABA-striatonigral fiber systems is discussed.