FURTHER EVIDENCE FOR A CENTRAL SITE OF ACTION FOR THE ANTINOCICEPTIVE EFFECT OF CLONIDINE-LIKE DRUGS

Using the mouse tail-irmersion test (48° C), the antinociceptive effects (AE) of clonidine and of a related analogue St-91 were examined after peripheral and intracerebroventricular (icv) administration. No AE was found after peripheral administration of St-91 at sub-toxic doses. Clonidine produced a profound and linear dose-dependent AE by this route. Both agents were active after icv administration, clonidine significantly more so than St-91 on a weight basis. The possibility that this evidence implicates a central site of action for the AE produced by clonidine-like agents is discussed. © 1979.