Activity on the central nervous system of Himanthalia elongata.

We report the effects of a fraction (F1) obtained from Himanthalia elongata on spontaneous locomotor activity, hypermotility, motor coordination, rectal temperature, pentobarbitone-induced hypnosis, pentylenetetrazole-induced convulsions and analgesic activity in the writhing and hot-plate tests. This fraction caused very significant reductions in spontaneous locomotor activity, hypermotility, and rectal temperature. It postponed pentylenetetrazole-induced death and a slight increase of sleeping time was noted in the sodium pentobarbital-induced sleep test . A significant effect was only noted on motor coordination at high doses. F1 showed significant analgesic effects on the hot-plate test at all of the assayed doses but not on the writhing test, where only the highest dose showed significant activity.