PERIPHERAL PLASMA CORTICOTROPIN‐RELEASING FACTOR CONCENTRATION DOES NOT CORRELATE WITH AUGMENTED COLONIC MOTILITY IN RESPONSE TO RESTRAINT STRESS IN RATS

Abstract

1. Corticotropin-releasing factor (CRF) alters colonic motor function in response to restraint stress. It remains unclear whether peripheral CRF released by restraint stress correlates with stress-mediated colonic motility. 2. One strain gauge transducer was sutured on the serosal surface of the mid colon and a silastic cannula was inserted into the jugular vein. Seven days after surgery, the wires from the transducers were connected to the recording system and colonic motility was recorded. Rats were subjected to restraint stress for 90 min and blood samples were obtained every 30 min. 3. Immediately after the start of stress loading, phasic contractions were observed that lasted during restraint stress loading. Intracisternal injection of CRF elicited rapid augmentation of colonic motility, similar to that of restraint stress. 4. The plasma CRF concentration (4 pg/mL) remained unaltered within the first 30 min after stress loading, but increased gradually to 23 pg/mL at 90 min after the beginning of restraint stress. There was no positive correlation observed between plasma CRF concentrations and restraint stress-stimulated colonic motility. 5. These findings indicate that central CRF has a predominant role in stress-induced augmentation of colonic motility. It remains unclear whether a delayed response of plasma CRF concentrations in response to restraint stress is involved in mediating colonic motility.