INTRACEREBROVENTRICULAR TREATMENT WITH AN ANTISENSE OLIGODEOXYNUCLEOTIDE TO KAPPA-OPIOID RECEPTORS INHIBITED KAPPA-AGONIST-INDUCED ANALGESIA IN RATS

In vivo treatment with an antisense (AS) phosphorothioate oligodeoxynu cleotide (oligo) to the rat kappa-opioid receptor selectively inhibite d kappa-mediated analgesia in the rat cold-water tail-flick test. Intr acerebroventricular (i.c.v.) AS oligo significantly inhibited the anal gesic effect of i.c.v. spiradoline, but not that of mu- or delta-opioi d agonists. The dose-effect curve for s.c. spiradoline was shifted to the right after AS, but not missense or sense oligo treatment. Thus, A S oligos provide another technique with which to selectively manipulat e opioid receptors and further support the role of non-mu opioid recep tors in mediating analgesia in rats.