Effect of indoramin and propranolol on cardiovascular response to cold in hypertensive patients

Immersion of the hand into ice water (cold-pressor test) in nine hypertensive subjects induced elevation of mean blood pressure, increase of vascular resistance in the extremities, decrease of blood flow in the extremities, and increase in heart rate. The preejection phase of systole was not altered. Indoramin and propranolol, each alone and together, attenuated the pressor and other cardiovascular responses. Submaximal exercise increased heart rate during placebo treatment, a response only partially attenuated by indoramin, propranolol, and their combination, but it did not induce changes in mean blood pressure during any of the treatments.