Comparison of behavioral changes in cats treated with intracerebroventricular 6-hydroxydopamine and reserpine.

In singly- and group-housed cats, an intraventricular injection of 6-hydroxydopamine (6-OHDA) in doses up to 1.0 mg, after a latent period of 1 to 3 days, evoked motor responses including tremor, ataxia, rigidity, weakness with adynamia and clonic-tonic convulsions. However, the intraventricular administration of 6-OHDA in a dose of 2.0 mg in group-housed cats, also after a latent period of 1 to 3 days, caused aggression, a restlessness, irritability, rage, fear, threat, attack, fighting and flight. These responses were accompanied by autonomic signs of mydriasis and dyspnoea and motor changes including tremor, ataxia, rigidity, weakness with adynamia and clinic-tonic convulsions. In the singly-housed cat only the latter motor phenomena were observed after the higher dose. Intraventricular injection of reserpine (0.5-1.0 mg) in both singly- and group-housed cats produced catalepsy, sedation, miosis, ptosis, defecation and micturition as well as motor responses of tremor, rigidity and akinesia. It is concluded that although 6-OHDA and reserpine evoke different behavioral effects, the motor changes are similar.