Newly synthesized neuropeptides with central nervous activity in mice

Abstract

Aim: Object of present study are two newly synthesized neuropeptides with short chains: analogues of Tyr-MIF – 1 with code P1 and of Nociceptine with code P2. Materials and Methods: On male albino mice we studied the changes in the cognitive functions of animals after 3, 7 and 14-days pretreatment with both compounds (5 mg/kg intraperitoneally- i.p.) via: step through test (for learning and memory), Rot-a-rod test (for muscular coordination) and Hole board test (for exploratory activity). Their potential analgesic effect was evaluated by Acetic acid test and their activity on the cen-tral nervous system (CNS) was evaluated via interaction with hexobarbital (HB- 100 mg/kg i.p). Statistics were performed with Student – Fisher test.Results: On the 3rd day after treatment daily both compounds had no effect on cognitive functions of animals, but on the 7th day the analogue of Tyr- MIF –1 (peptide P1) significantly improved the memory (by 60%) and decreased also the exploratory activity of treated animals. The analogue of Nociceptine-P2 demonstrated significant dose-dependent analgesic effect. On the 14th day both compounds improved neuro-muscular coordination of animals. In single doses two compounds shorten significantly duration of hexobarbital narcosis (Р1 by 40% and Р2 by 50%) via unknown mechanism, probably related to functional antagonism between the neuropeptides and hexobarbital on CNS level. Conclusion: Newly synthesized neuropeptides are promising biological active substances with effect on CNS. The analogue of Tyr-MIF–1 improves cognitive function of animals and the analogue of Nociceptine has significant dose-dependent analgesic effect