INVOLVEMENT OF 5-HT3 RECEPTOR IN THE PRESSURE-INDUCED INCREASE IN STRIATAL AND ACCUMBENS DOPAMINE RELEASE AND THE OCCURRENCE OF BEHAVIORAL-DISORDERS IN FREE-MOVING RATS

Rats exposed to high pressure developed locomotor and motor activity ( LMA) that correlated with. an increase of DA release in both the nucle us accumbens and the caudate-putamen. We investigated the effects of t he 5-HT3 receptor antagonist MDL 72222 on these pressure-induced neuro chemical and behavioral disorders. MDL 72222 totally blocked the press ure-induced increase in accumbens DA release and the development of LM A, whereas it only reduced the increase in striatal DA release. This s uggest that both LMA and the increase of DA release in the nucleus acc umbens, but not in the caudate-putamen, could specifically result from a 5-HT3 receptor activation in rats exposed to high pressure.