THE ROLE OF HYPOPHYSEAL AND ADRENAL MECHANISMS IN THE HYPOALGESIC RESPONSE TO NONCONTINGENT FOOD DELIVERY IN THE RAT

Exposure to non-contingent food delivery has been shown to elicit an i ncrease in nociceptive thresholds in rats. This hypoalgesia has previo usly been shown to be reversible by the opiate antagonist naloxone. Gi ven that most opioid forms of SIA are found to rely on an intact pitui tary-adrenal axis, this research examined the possibility that the hyp oalgesic response to non-contingent food delivery is also hormonally m ediated. Hypophysectomy (Expt. 1) but not bilateral adrenalectomy (Exp t. 2) was found to completely attenuate the hypoalgesic response to no n-contingent food delivery. Preliminary data from ongoing research is presented that points to the possible involvement of the hypophyseal p eptides beta-endorphin and adrenocorticotropin hormone (ACTH).