Catalepsy after microinjection of haloperidol into the rat medial prefrontal cortex.

To investigate the behavioural role of mesocortical dopamine innervation we performed bilateral microinjections of haloperidol into various parts of the rat frontal cortex and into adjacent subcortical forebrain structures. Haloperidol (2.5 micrograms/0.5 microliter) locally injected into the medial prefrontal cortex or into the rostral part of the neostriatum resulted in the development of catalepsy as measured in the bar test. In contrast, injections of haloperidol into the nucleus accumbens, more caudal parts of the neostriatum, anterior cingulate cortex, rostral and lateral parts of the prefrontal cortex and into the lateral ventricles failed to induce catalepsy. It is concluded that blockade of dopamine receptors located in the rostral neostriatum and in the medial prefrontal cortex contributes to the development of haloperidol induced catalepsy.