Effects of Skeletonema costatum extracts on the central nervous system.

We report the effects of aqueous extracts of the microalga Skeletonema costatum Greve (Cleve) (Bacillariophyceae) on spontaneous motor activity, rectal temperature, motor coordination, amphetamine-induced hypermotility, exploratory behaviour, muscle relaxation, catalepsy, conditioned avoidance responses, oxotremorin-induced cholinergic syndrome, and pentylenetetrazole-induced convulsions. The S. costatum extract at dosages of 310 and 620 mg/kg works like an antidopaminergic drug with anticholinergic properties, that does not induce catalepsy and with a notable muscle relaxing activity.