MOLECULAR MECHANISMS INVOLVED IN THE IMPLEMENTATION OF ANALGESIC EFFECTS OF 1-DEAMINO-8-D-ARGININE-VASOPRESSIN UNDER THERMAL EXPOSURE AND ELECTROCUTANEOUS STIMULATION IN RATS

The aim of the study was to evaluate the effect of a synthetic vasopressin analog, 1-

deamino-8-D-arginine-vasopressin (DDAVP) on pain sensitivity, monoamine and brain-derived neurotrophic factor (BDNF) content in the parietal cortex and spinal cord in the tail-immersion test and electrocutaneous stimulation in rats. DDAVP was administered intranasally in a thermal pain model at 0.002 µg/day (0.01 µg/course) and 2 µg/day (10 µg/course); for electrocutaneous irritation ― 0.02 µg/day (0.1 µg/course) and 2 µg/day (10 µg/course). Serum corticosterone and BDNF levels in the parietal cortex and spinal cord were determined using enzyme-linked immunosorbent assay. The levels of NE, 5-HT, DA and their metabolites (DOPAC, HVA, 5-HIAA) in the brain were determined using high-performance liquid chromatography. DDAVP reduced pain sensitivity regardless of the type of pain and doses administered. During electrocutaneous stimulation, DA and 5-HT contributed to analgesia at the supraspinal level; 5-HT, DA and NE ― at the spinal level. DDAVP did not affect the corticosterone level in the blood of rats with different types of pain. The participation of monoamines and BDNF in the analgesic effects depended on the type of exposure and dose of the drug. NE and BDNF at the supraspinal and spinal levels, 5-HT at the spinal cord level were involved in the implementation of analgesia in the thermal pain model. During electrocutaneous stimulation, DA and 5-HT contributed to analgesia at the supraspinal level; 5-HT, DA and NE ― at the spinal level.