Evaluation of behavioral, clinical and antinociceptive effects of syntetic factor CNF021.03 obtained from venom of serpents Crotalus durissus terrificus in horses: comparison with morphine, U50-488H and phenylbutazone

Abstract

There is much to be studied to care pain efficiently. Morphine, an agonist of µ receptor, is the analgesic prototype drug to promote potent analgesia. To attempt minimizing side effects (stereotopy, locomotion stimulation and respiratory depression) induced by µ opioid agonist, several studies have been conducted to evaluate kappa opioid receptors agonists. Venom of Crotalus durissus terrificus promotes expressive analgesia mediated by kappa (central and peripheral action) and delta receptors (peripheral action). Recently, an analgesic factor (ENPAK) present in crude venom was isolated and it was possible to synthesize the analgesic factor (CNF021.03). This study will evaluate antinociceptive effect of synthetic analgesic factor CNF021.03 by determination of response onset to thermal stimulation induced by a dolorimetric lamp and cutaneous primary or secondary hyperalgesy will be evaluated, by von Frey filaments, after incisional and thermal tests of inflammatory pain. These effects will be compared to standard drugs, like morphine, U50-488H and phenylbutazone. Additionally, behavioral and clinical effects of CNF021.03 will be evaluated by checking heart and respiratory rates, rectal temperature, intestinal motility, latency to urine and defecation, presence of sedation/excitation, ataxia, drooping of the labium and/or upper eyelids and spontaneous locomotor activity. (AU)