The inhibitory effect of the cerebellar fastigial stimulation on ADH secretion.

1. Both cardiovascular and antidiuretic hormone (ADH) responses to some neural inputs were examined in paralysed anaesthetized cats.2. Carotid occlusion elicited cardiovascular responses and increased ADH secretion. When the electrical stimulation of discrete loci of the cerebellar fastigial nucleus (fastigial pressor area) was superimposed on carotid occlusion, cardiovascular responses were further facilitated, while ADH secretion was inhibited.3. The fastigial stimulation alone elicited facilitory cardiovascular responses composed of hypertension and tachycardia, and the fastigial pressor response (FPR), but did not evoke any consistent ADH response.4. These facts indicate that cerebellar modulation of ADH secretion occurs not directly via the hypothalamo-hypophysial system but through the lower brain stem to which both carotid sinus nerves and outflows from the fastigial pressor area project.5. We conclude that the fastigial pressor area is specific for not only cardiovascular and other autonomic responses but pituitary hormonal response.