gzr-123 and Pain

The pain threshold effects of a neurotensin NT (8 - 13) dipeptide analog (dilept), morphine, and their combination have been studied using the tail flick test in rats. The animals of another experimental group were administered with morphine in increasing doses (10 - 20 mg/kg, i.p.) for 5 days in order to induce the state of dependence. The physical dependence on morphine was evaluated in the open-field test by monitoring 16 specific behavioral signs of withdrawal syndrome (WS) induced by the opioid receptor antagonist naloxone, after which the WS total index was calculated. It was established, that dilept (1.6 mg/kg, i.p.) produced a mild analgesic effect via increasing the pain threshold by 34% (p < 0.01), did not effect on the morphine analgesic effect, and decreased the expression of morphine WS by 29.1 and 37.5% (p < 0.01) after a single or subchronic administration, respectively. These behavioral effects of dilept were accompanied by normalization of dopamine and serotonin turnover in the hypothalamus, frontal cortex, and striatum of experimental animals.

Topics: Animals; Dopamine; Frontal Lobe; Hypothalamus; Male; Morphine; Naloxone; Narcotic Antagonists; Narcotics; Neurotensin; Pain; Pain Threshold; Peptide Fragments; Proline; Rats; Serotonin; Severity of Illness Index; Substance Withdrawal Syndrome; Tyrosine