Adrenal catecholamine secretion during stimulation of the nasal mucous membrane in the rabbit.

1. Left adrenal venous blood was collected in anaesthetized rabbits and analysed for catecholamine content by either a fluorimetric technique or a bio-assay method using the blood pressure of the pithed rat.2. Stimulation of the nasal mucous membrane with ether vapour or water caused apnoea, bradycardia, a rise in arterial blood pressure and an increase in adrenal medullary catecholamine secretion.3. During the pre-stimulation control periods adrenaline constituted 66% of the total catecholamine present in adrenal venous blood and noradrenaline 34%. These proportions altered during stimulation of the nasal mucous membrane to 72 and 28% respectively. Electrical stimulation of the left splanchnic nerve produced a secretion composed almost entirely of adrenaline.4. The increased catecholamine output elicited during stimulation of the nose occurred in animals whose pulmonary ventilation was maintained constant by means of a pump. It was abolished, however, by local anaesthesia of the nasal passages or by surgical division of the left splanchnic nerve.5. The increased secretion of catecholamines is therefore reflex in nature, and evidence is presented that it is the result of a primary reflex from the nose.