Antihypertensive effects of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) in conscious dogs.

Low doses of 8-OH-DPAT (10 and 25 micrograms/kg) administered subcutaneously (s.c.) to renal hypertensive mongrel dogs caused decreases in systolic blood pressure which persisted for 3 h. Mild salivation and hyperventilation were observed with both doses. A short-lasting (less than 60 min) depressor response was seen with 100 micrograms/kg s.c. Prominent hyperventilation and salivation accompanied this response. A still higher dose (250 micrograms/kg s.c.) induced tremor, signs of anxiety and occasional vomiting in addition to the hyperventilation and salivation. Paradoxically, no cardiovascular activity was noted at this dose.