Localized Response in the Posterior Hypothalamus Following Intravenous Administration of Pitressin

¹ From the Department of Anatomy, University of California, Los Angeles and Veterans Administration Center, Los Angeles, California

Electrical recording experiments performed on adult cats have revealed an area in the hypothalamus, lateral and slightly rostral to the mammillary bodies, which responds characteristically to intravenous injections of Pitressin. Spike activity at a frequency of 4–10/sec. was observed in this area and generally started 4–8 minutes after the injection of 1 or 2 pressor units of Pitressin. The electrical discharge was observed to last for periods of up to 35 minutes and commenced well after the blood pressure response returned to normal. Epinephrine and other vasopressor drugs did not elicit the hypothalamic response observed with Pitressin.