Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Abstract
MAS MT is a myotropic decapeptide isolated from Manduca sexta.
This peptide exerts stimulatory effect on insects heart-beat frequency. The present
study was undertaken in order to determine a probable antinociceptive effect in
rats of native synthetic decapeptide, MAS MT-I and its two analogs, heptapeptides
MAS MT-II and MAS MT-III. All these peptides were applied directly into the
lateral brain ventricle (icv) at three doses: 10, 25 and 50 nmol. The analgesic
(antinociceptive) effect was evaluated by a tail immersion test. It was found that
two doses of MAS MT-I: 25 and 50 nmol induced significant antinociceptive
effect, while MAS MT-II and MAS MT-III exert a less antinociceptive effect in
comparison with native MAS MT-I. Prior icv administration of naloxone, an opioid
antagonist weakly blocked MAS MT-I effect. We conclude that antinociceptive
effect of MAS MT-I in rats is not mediated by central opioid system