Amphetamine-induced locomotor activity and stereotypy after kainic acid lesions of the striatum.

Kainic acid injections were used to destroy cell bodies in the striatum without affecting afferent terminals of fibres of passage. Substantial decreases in choline acetyltransferase and glutamic acid decarboxylase were found particularly in the dorsal half of the striatum but no alteration in the marker enzyme for dopamine terminals, tyrosine hydroxylase. The locomotor activity inducing and stereotypical effects of the psychomotor stimulant drug, d-amphetamine, were tested in these animals and a marked and consistent $\text{increase}$ in the effects of amphetamine was found on both measures. This is interpreted in terms of a disruption of the striatonigral feedback system and as suggesting a possible dissociation of function within the striatum between the dorsal and the ventral parts.