Enhancement of clonidine (0.125 mg kg−1, s.c.) and guanabenz (0.30 mg kg−1, s.c.) antinociception by the KATP openers diazoxide (100 mg kg−1, p.o.), minoxidil (10 μg per mouse i.c.v.) and pinacidil (25 μg per mouse, i.c.v.) in the mouse hot plate test. Vertical lines represent s.e.mean; between 12 and 16 mice were tested. *P<0.05 in comparison with corresponding analgesic drug-treated mice.