STRESS THROUGH HANDLING FOR VAGINAL SCREENING, SEROTONIN, AND ACTH RESPONSE TO ETHER

The effect of duration of handling for vaginal smear screening on the adrenal weight and acute ACTH response to ether were examined in 4-day -cycling female rats, sacrificed at 97-103 days of age on diestrus-2 a fter evaluation of resistance to handling, thymus weight, and hypothal amic serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). Prolong ed handling paralleled increased resistance (behavioral response) to h andling and adrenal weight but was inversely related to thymus weight. The hypothalamic 5-HT, 5-HIAA, and 5-HIAA/5-HT ratio, compared to con trols with similar conditions of handling, were not modified after 2.5 min of ether despite the ACTH rise. In ether-stressed rats, the ACTH response to ether was lower after prolonged handling compared to short handling paralleling decreased thymus weight. In contrast, 5-HT, 5-HI AA, and the 5-HIAA/5-HT ratio were higher, paralleling increased resis tance and adrenal weight. The results suggest chronic activation of th e hypothalamo-pituitary-adrenal axis with positive serotonergic involv ement after prolonged handling and resistance during vaginal screening and a negative implication of this activation on the acute ACTH respo nse to ether.