Regulation of Somatic Pain Sensitivity under the Circumstances of Indometacin‐InducedGastric Injury: Participation of Cortricotropin‐Releasing Factor

Abstract

In the present study we investigated the somatic pain sensitivity under the circumstances of indometacin (IM)‐induced gastric ulceration and effect of cortricotropin‐releasing factor (CRF) on the somatic pain sensitivity under the circumstances in conscious rats. IM (35 mg/kg) was administered subcutaneously to preliminary (24h) fasted as well as fed rats. CRF was injected 30 min before IM administration. The somatic pain sensitivity was estimated by tail flick latencies. A single IM administration caused the gastric erosion formation 4 h after the injection only in fasted but not fed rats. IM‐induced gastric injury was accompanied by an increase in tail flick latency in fasted rats. Pretreatment with CRF prevented this increase. CRF by itself did not influence the somatic pain sensitivity. Since we did not observe any changes in tail flick latency in fed IM‐treated rats without gastric mucosal lesions, it was reasonable to assume that an increase in tail flick latency in preliminary fasted IM‐treated rats was associated with the pathological changes in the gastric mucosa, but not with IM‐caused analgesic action by itself. Thus, IM‐induced gastric injury resulted in the suppression of the somatic pain sensitivity and CRF might be involved in regulation of the somatic pain sensitivity under the circumstances in conscious rats. Supported by the Russian Scientific Foundation (grant N 14‐15‐00790).