Humoral factors released from intracranial sources during stimulation of reticular formation

Abstract

Previous work has suggested that catecholamines might function as transmitter substances in portions of the reticular activating system. In this study, we used classical autopharmacological methods in an effort to detect catecholamine release into the systemic circulation of the encéphale isolé preparation during stimulation of the reticular formation. Fluctuations of blood pressure and movements of the denervated nictitating membrane were observed after exclusion of effects mediated by the cranial nerves and sympathoadrenal discharge. Since these effects were not blocked by Dibenzyline, and could be reproduced by small doses of Pitressin, they were ascribed to the release of vasopressin from the neurohypophysis rather than to catecholamine release. Some preliminary data were obtained on the localization in the midbrain of a pathway that appears to influence the hypothalamoneurohypophysial system, and that may possibly be responsible for the antidiuretic effects of pain and emotional excitement.