Endocrinology, Vol 114, 2148-2153, Copyright © 1984 by Endocrine Society

ARTICLES

Electrolytic lesions of the dorsal rostral pons prevent adrenocorticotropin increases after hemorrhage

AM Lefcort, DG Ward and DS Gann

To determine if a discrete area of the dorsal rostral pons in the region of the locus coeruleus (LC) is essential for the reflex response of ACTH to hemorrhage, chloralose-anesthetized cats with bilateral electrolytic (11 cats) or sham (3 cats) lesions were challenged with a 15 ml/kg X 3 min hemorrhage. Sequential arterial blood samples taken at -6, -3, 3, 6, 9, 15, and 21 min from hemorrhage were analyzed for ACTH content. Cats were grouped according to whether plasma ACTH increased in response to hemorrhage. Bilateral lesions in 7 cats with an area in common, which lay within the LC complex, blocked the reflex increase in plasma ACTH in response to hemorrhage which was seen in 3 sham-lesioned cats, in 3 cats with lesions that did not infringe in this region bilaterally, and in 1 cat with lesions that infringed only on the medial-ventral aspect of the LC-subcoeruleus. These findings suggest that hemodynamic information responsible for the reflex response of ACTH to hemorrhage of this magnitude passes through a discrete region of the dorsal rostral pons.