ADRENOCORTICAL RESPONSES TO OLFACTORY STIMULATION IN RATS WITH HYPOTHALAMIC ISLANDS

Abstract

Department of Neurology, Hadassah University Hospital, Jerusalem, Israel (Received 27 October 1975) There exists both anatomical and electrophysiological evidence that olfactory pathways project to the hypothalamus (Scott & Pfaffmann, 1967; Scott & Chafin, 1975). Hypothalamic island preparations were used to differentiate between 'systemic' stresses which produced normal adrenocortical responses and 'neurogenic' stresses which caused a reduced adrenal discharge (Feldman, Conforti, Chowers & Davidson, 1970; Feldman, Conforti & Chowers, 1975). This paper describes the role of the hypothalamic neural connexions in the mediation of the adrenocortical response following olfactory stimulation. Experiments were performed on male albino rats of the Hebrew University strain weighing approximately 250 g. Adrenocortical responses to ether stress and to olfactory stimulation, as determined by changes in plasma corticosterone levels (Click, von Redlich & Levine, 1964), were studied in 33 intact animals and in 33 rats with hypothalamic islands (Halasz & Pupp, 1965). The protocol consisted of submitting