[D-Met2]-FMRFamide (DMFa): production of naloxone-sensitive antinociception in mouse tail-flick test.
Considerable data support the hypothesis that mammalian FMRFamide (Phe-Met-Arg-Phe-NH2) or mammalian FMRFamide-related peptides (FaRPs) function as endogenous antiopiates (for review see Raffa, 1988). We report here that central administration (i.c.v.) of a FaRP with D-amino acid substitution in the second position, i.e. [D-Met2]-FMRFamide (DMFa), produces dose-related, naloxone-reversible antinociception in the mouse tail-flick test. Hence, this modification appears to confer agonist-like activity.
Raffa
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RB
CNS Research, R.W. Johnson Pharmaceutical Research Institute, Spring House, PA 19477-0776.
Connelly
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CD
D000700:Analgesics; D000818:Animals; D004305:Dose-Response Relationship, Drug; D019835:FMRFamide; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D009270:Naloxone / Q000494:pharmacology*; D009479:Neuropeptides / Q000494:pharmacology*; D011930:Reaction Time / Q000187:drug effects*; D013237:Stereoisomerism
D000700:Analgesics; D009479:Neuropeptides; D009270:Naloxone; D019835:FMRFamide