Analgesic activity of spiradoline mesylate (U-62,066E), a kappa opioid agonist in mice - PubMed (original) (raw)

Comparative Study

Analgesic activity of spiradoline mesylate (U-62,066E), a kappa opioid agonist in mice

M Kunihara et al. Life Sci. 1989.

Abstract

The present study was undertaken to evaluate the analgesic potency of spiradoline mesylate, a k(kappa) opioid agonist, in comparison with that of morphine, by hot plate, tail-pinch and acetic acid-induced writhing assay. The ED50 values of spiradoline in hot plate, tail-pinch and acetic acid-induced writhing assay were 0.46, 0.26 and 0.20 mg/kg, respectively. The analgesic potency of spiradoline was 1.5-7.0 times higher than that of morphine. Repeated treatment with spiradoline as well as morphine developed tolerance to the analgesic effect in hot plate assay. In mice developed tolerance to one analgesic, response to the other analgesic did not alter compared to saline-treated mice. Single administration of spiradoline (1.5 and 3 mg/kg, s.c.) did not inhibit morphine-induced analgesia. These results suggest that spiradoline has more potent analgesic activity than morphine, presumably mediated through stimulation of receptors different from morphine.

PubMed Disclaimer

Similar articles

Cited by

Publication types

MeSH terms

Substances