Locomotion and stereotyped behaviours induced by 1-amino-3,5-dimethyladamantane (D 145) and apomorphine in the rat: a comparison

Abstract

The locomotion and stereotyped behaviours induced by the two dopamine agonists, 1-amino-3,5-dimethyladamantane (D 145) and apomorphine in rats have been investigated using a holeboard apparatus. Unlike apomorphine, D 145 did not induce compulsive gnawing, but it did induce locomotion dose-dependently. However, the pattern of locomotion was different from that induced by apomorphine and the locomotion itself was potently antagonized by haloperidol but not by sulpiride; this is the opposite to apomorphine-induced locomotion. This indicates that locomotion induced by dopamine agonists is not a unitary phenomenon but that different 'types' of locomotion, with different pharmacological properties, can be induced. Low doses of D 145, given before apomorphine, reduced apomorphine-induced gnawing and enhanced apomorphine-induced locomotion. The long lasting 'priming' effect known to occur after repetitive injections of apomorphine was not mimicked by D 145. Apomorphine and D 145 are considered to be two specific DA agonists; their behavioural-pharmacological profiles, however, are quite different.