Experimental study of antinociceptive potency of dipeptide GB-115 during chemical and thermal stimulation

The study examined the antinociceptive potency of dipeptide compound GB-115 (amide N-6-phenylhexanoyl-glycyl-L-tryptophan) during thermal and chemical noxious stimulation of mice. Peroral administration of GB-115 (0.1-20 mg/kg) decreased the incidence of abdominal contractions induced with intraperitoneal acetic acid (0.75%). This effect was comparable to that of sodium diclofenac (20 mg/kg); it was only partially antagonized with naloxone indicating the presence of significant non-opioid component in analgesic effect of GB-115. Ability of this dipeptide to moderate the nociceptive response in tail flick test under a non-selective blockade of the opioid receptors with naloxone and the absence of similar analgesic potency assessed in the hot plate test attest to predominant effect of GB-115 on spinal opioid receptors.