INTRACEREBROVENTRICULAR LA3-INDUCED MOTOR ACTIVATION IN RATS( BUT NOTGD3+ INHIBITS COCAINE)

In the present work the effects of i.c.v. administration of La3+ and G d3+ on the motor stimulant effect of cocaine in rats were studied. Bot h La3+ and Gd3+ failed to influence basal motor activity. However, the two metal ions differ in modulation of cocaine-induced activation of motor activity. While Gd3+ (10.0, 20.0 and 40.0 mM/1 ml) did not influ ence significantly the cocaine effect, La3+ (0.1, 1.0 and 10 mM/1 mi) inhibited cocaine-induced motor activation in a dose-dependent manner. The results suggest the possible involvement of La3+- but not Gd3+-se nsitive calcium channels in the locomotor stimulant effect of cocaine.