Kamei J, Hitosugi H, Kawashima N, Misawa M, Kasuya Y
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
Neurosci Lett. 1993 Apr 16;153(1):69-72. doi: 10.1016/0304-3940(93)90079-z.
Intrathecal administration of endothelin-1 (ET-1) produced dose-dependent antinociceptive effects in the tail-flick test. The antinociceptive effects of ET-1 were attenuated significantly by pretreatment with naloxone and the delta receptor-selective antagonist naltrindole. The antinociceptive effects of ET-1 were also significantly attenuated by pretreatment with verapamil, an L-type Ca(2+)-channel blocker. These results suggest that the mechanism underlying the antinociceptive effects of ET-1 involves mediation, at least in part, by Ca(2+)-induced release of endogenous opioids, which act on delta-opioid receptors.
