Stereotypy after intracaudate injection of atropine in the rat

Bilateral injection of atropine in the caudate nucleus evokes a dose-related stereotyped rearing in the rat. The response was measured in an objective and quantitative way by means of an automatic device (erigometer) developed in this laboratory. The effect of intracaudate atropine is fully abolished by intraperitoneal pretreatment with triperidol. Previous experiments had shown that also the stereotypy caused by i.p. atropine was inhibited by intracaudate injection of triperidol. Thus, it can be concluded that the cause of atropine stereotypy is a disequilibrium of the striatal dopaminergic-cholinergic systems, irrespective of the fact whether the original dopaminergic tone within the striatum is decreased, normal or higher than normal.