Syracuse

We report on the biochemical, cellular and pharmacological activities of SQA-neuropeptide FF Ser-Gln-Ala-Phe-Leu-Phe-Gln-Pro-. Ž Gln-Arg-Phe-NH , a peptide sequence contained in the human neuropeptide FF neuropeptide FF, Phe-Leu-Phe-Gln-Pro-Gln-Arg-Phe-2 . NH precursor. Quantitative autoradiography revealed that, in the superficial layers of the rat spinal cord, SQA-neuropeptide FF 2 2 i Ž . did neuropeptide FF K s 0.38 nM . In acutely dissociated mouse dorsal root ganglion neurones, SQA-neuropeptide FF reduced by 40% i the depolarisation-induced rise in intracellular Ca 2q as measured with the Ca 2q indicator, Fluo-3. In mice, 1DMe and SQA-neuropeptide Ž . FF dose-dependently inhibited the antinociceptive effect of intracerebroventricular i.c.v. injections of morphine, but SQA-neuropeptide FF was less potent than 1DMe. Furthermore, SQA-neuropeptide FF, as well as 1DMe, produced marked hypothermia following third ventricle injections in mice. These data demonstrate that the human peptide, SQA-neuropeptide FF, exhibits biochemical and pharmacological properties similar to those of neuropeptide FF or neuropeptide FF analogues, and belongs to the neuropeptide FF family.