Deltorphin pharmacological activity

Role of D-glucopyranosyl moiety in the pharmacological activity of Deltorphin C and dermorphin. 

Further pharmacological effects of deltorphins have been demonstrated under various experimental conditions. D-Ala-deltorphin improves memory consolidation in a passive avoidance apparatus in mice this effect is abolished by naltrindole [75]. D-Ala-deltorphin-II caused hypothermia in cold-adapted animals [76]. In contrast to mu opiate agonists, D-Ala-deltorphin-I, at low doses, stimulates respiratory activity in fetal lambs, and this effect is blocked by simultaneous administration of naltrindole [77], The peptide D-Ala-deltorphin-II inhibits diarrhea induced by castor oil and colonic bead expulsion, but it leaves the rate of transit through the small intestine unchanged [78,79]. By the SC route D-Ala-deltorphin-I inhibits acidified alcohol-induced gastric mucosal lesions [80], but by the ICV route, it fails to affect gastric secretion [81], The peptide is involved also in the control of ingestive behavior. It stimulates the intake of food [82] and of sucrose [83],... 

While the high affinity for the g-opioid receptor was confirmed in the in vitro pharmacological assay (guinea- pig ileum), in vivo antinociception apparently failed to correlate with high g-opioid receptor activity however, the activity profile of peptide 1 [DMT1] deltorphin B was more closely related to that of the 8- selective opioid peptides 2 (deltorphin B) and 3 (deltorphin C). 

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