TURNING IN CIRCLES - NEUROPHARMACOLOGY OF ROTATION

Rats with unilateral lesions of the nigrostrial system rotate when administered dopaminergic agents. The same agents also induce rotation, though at lower rates, in normal animals. Despite the apparent simplicity of the rotatory response, variations in methodology among studies may alter the kind and/or magnitude of rotation data obtained. In some cases, due to insufficient control procedures, inaccurate or erroneous interpretations may be reached. The importance of considering several testing parameters is discussed. It is concluded that rotation is primarily due to asymmetric dopaminergic nigrostriatal function, although other pathways mediated by norepinephrine, serotonin, acetylcholine and GABA [.gamma.-aminobutyric acid] appear to have modulatory roles.