Adrenergic Control of the Peripheral Circulation in Cardiomyopathic Hamsters with Heart Failure

¹ Cardiovascular Division, Department of Internal Medicine, University of Iowa College of Medicine, and the Veterans Administration Hospital Iowa City, Iowa 52240

Adrenergic control of the peripheral circulation was studied in cardiomyopathic hamsters to determine if the functional status of terminal vascular sympathetic nerve endings is augmented in heart failure. Four groups of hamsters were studied: myopathic hamsters with heart failure (average age 296 days), myopathic hamsters without heart failure (average age 171 days), and two corresponding control groups of randomly bred hamsters matched for age. In hamsters with heart failure, the concentration of catecholamines in hearts, aortas, and femoral arteries was reduced compared with that in corresponding control hamsters. In myopathic hamsters without heart failure, the concentration of catecholamines was reduced in femoral arteries, but it was not reduced in hearts or aortas. Resting vascular resistance and vasoconstrictor responses to sympathetic nerve stimulation, norepinephrine, and angiotensin in the perfused hindquarters was reduced in hamsters with heart failure but not in myopathic hamsters without heart failure. These studies suggest that the functional status of terminal sympathetic nerve endings in blood vessels of the extremities is not augmented and may be reduced in this model of heart failure. Studies on other models of heart failure are needed to determine whether the absence of increased vascular catecholamines and the absence of augmented responses to sympathetic nerve stimulation are characteristic of heart failure in general or are unique to this model that has characteristics of highoutput failure.

Submitted on August 21, 1972
Accepted on May 14, 1973