MU-RECEPTOR AND G(I)2-ALPHA ANTISENSE ATTENUATE [D-MET(2)]-FMRFAMIDE ANTINOCICEPTION IN MICE

FMRFamide (Phe-Met-Arg-Phe-NH2) and several analogs produce centrally- mediated, naloxone-reversible antinociception, but have minimal affini ty for opioid receptor (sub)types. In the present study, the antinocic eption in mice (55 degrees C tail-flick test) produced by supraspinal (intracerebroventricular; ICV) administration of [D-Met(2)]-FMRFamide (a stable analog of FMRFamide) was attenuated by pretreatment with ICV oligodeoxyribonucleotide antisense to the opioid mu receptor or by an tisense to the G(i)2 alpha(G-protein subunit. These data suggest that [D-Met(2)]-FMRFamide produces its antinociception via an opioid intern euron. (C) 1998 Elsevier Science Inc.