The neurosecretory response to stress, anaesthesia, adrenalectomy and adrenal demedullation in the rat.

Abstract

1. The characteristic response to stress of hypophysial and hypothalamic neurosecretory material is described. It is encountered following a variety of stimuli involving pain, fear, or rage and is roughly proportional to the intensity and duration of the stimulus. 2. It is produced by ether anaesthesia, but not by the administration of chloroform, Nembutal or chloralose. In anaesthetized animals no further effects of pain or osmotic stimuli are detectable. Chloroform is the agent of choice when it is desired to sacrifice animals without altering neurosecretory morphology. 3. The amount of neurosecretory material in the unstimulated adrenalectomized animal is reduced but the neurosecretory response to stress persists following adrenalectomy and adrenal demedullation. 4. It is believed that the stainable neurosecretory substance is the morphological equivalent of posterior pituitary hormone and distinctions between hormone and carrier-substance are considered unnecessary. The role of the neurosecretory substance is discussed in relation to known anti-diuretic hormone responses, adrenal insufficiency, and the pituitary release of ACTH following stress.