Possible involvement of a dopaminergic pathway in the depressant effe ts of ouabain on the central nervous system

Small doses of ouabain given by intracerebroventricular (i.c.v.) injection in the conscious mouse and rat produce both catalepsy and hypothermia. In addition, pimozide, which can selectively inactivate dopamine receptors in the brain, produces similar pharmacological effects to ouabain when given by the same route of administration in the mouse, although a significant degree of sedation and catalepsy can be induced using doses of pimozide that have little effect on body temperature. Further observations involving the interaction of ouabain with the dopamine receptor stimulant apomorphine suggest that the catalepsy and hypothermia produced by ouabain both involve central dopaminergic pathways. Whereas the production of catalepsy appears to be the result of a dopamine receptor blockade, possibly in the corpus striatum, the production of hypothermia, although associated with increased brain dopamine levels, is not.