B-HT 920 STIMULATES FEEDING AND ANTAGONIZES ANOREXIA INDUCED BY ACTH AND IMMOBILIZATION

The influence of immobilisation and i.c.v. injection of ACTH on feeding in rats was examined using a new experimental model. An X-maze with alternate open and covered arms, each baited with standard laboratory chow was used, where individual rats were placed and observed for 5 min. Two essential aspects of the behaviour towards food were considered, namely, lasting and feeding. A number of parameters were applied to demonstrate the anorectic activity of ACTH and immobilisation, in accordance with data obtained using classical procedures for feeding analysis. ACTH at the dose used did not modify rat exploratory activity and grooming in the X-maze without food pellets. In the same X-maze feeding test, B-HT 920, a selective agonist of dopamine D2 receptors and alpha-2-adrenoceptors, shown earlier to have anxiolytic- and antidepressive-like properties in rats, enhanced appetite and exerted anxiolytic activity when injected ia.p. Pretreatment with B-HT 920 counteracted the restraint- and ACTH-induced effects. The results are discussed in the light of the relation between control of feeding and affective disorders. B-HT 920 activity seems to be of particular interest in view of its antagonism towards the anorexia elicited by two different agents reputed to have in common a key role in the stress-related disturbances of food intake.