SENSITIVITY TO MECHANICAL PAIN BASED ON SATIETY LEVELS IN WOMEN

The recent data have shown that in addition to biological and psychosocial mechanisms, individual pain perception can be altered by satiety level as well. Some studies confirm that there is a relationship between being fed by sucrose and hyperalgesia in animals, while others show that ketogenic diet can be associated with decreased pain sensitivity to thermal stimuli. It can be argued that the effect of satiety level on pain perception is mediated by gastrointestinal hormones and endogenous opioids. Pharmacological stimulation of kappa-opioid receptors decreases stress and promotes analgesia. Accordingly, these changes can be inhibited by applying antagonists. Our study aims to assess pain perception induced by mechanical experimental irritation in women during different satiety levels in follicular phase of ovarian-menstrual cycle. The sample of the study was comprised of volunteer students aged 18-23 (women, mean age 19,5±2,9). Ovarian-menstrual cycle of the women participating in the research were evaluated using the questionnaires. All the studies were performed in the follicular phase of menstrual cycle (7-11 days of the cycle). At the first stage, study was conducted in starvation state - after 10-12 hours after the last meal, the second stage - in primary, sensory-motor satiety 20-30 minutes after a mixed meal intake. Every participant has been offered a standard, mixed meal (including proteins, fats, carbohydrates). Mechanical pain sensitivity was evaluated using computerized algometer - AlgoMed (Medoc, Ltd, Ramat Yishai, Israel), which was delivering mechanical stimuli to the participants; Meanwhile, mechanical pressure threshold, mechanical pain threshold and pain tolerance threshold were determined. According to this data, the reason of relatively diminished pain perception during primary satiety should be alterations of gastrointestinal tract that take place after food ingestion: Mechano- and chemoreceptors of initial segments in digestive system, particularly in stomach and in duodenum get irritated; that is followed by activation of several humoral factors and duodenal afferentation. In addition, by some authors duodenal release of cholecystokinin is believed to be hypothetical cause of decreased pain sensitivity after 20-30 minutes from the last mixed meal and is thought to have antinociceptive effect on endogenous opioid system.