Complex of rapid movements and vocalization induced by RX336-M in mice: possible relevance to Tourette's syndrome

RX336-M (7,8-dihydro-5',6'-dimethylcyclohex-5'-eno-1',2',8',14 codeinone) induced a complex of simultaneous rapid movements of body parts accompanied by a single squeak-vocalization, which occurred at irregular intervals, when injected i.p. in mice. The complex included whole body jerks and head-shakes and its frequency was dose dependent between 0.1 and 20 mg/kg. Frequency after a 5 mg/kg dose was reduced by haloperidol (0.5-10 mg/kg, i.p.), ritanserin (0.1-10 mg/kg, i.p.) and ICI 169,369 (2.0 mg/kg, i.p.), suggesting the possible involvement of 5-HT(2A) and/or dopamine receptors. The possible relevance of the behavioural effects of RX336-M to the tics and vocalization of Tourette's syndrome is discussed.