Cold-induced potentiation of alpha 2-adrenergic vasoconstriction in primary Raynaud's disease.

Objective: To determine the effects of local cooling on alpha-adrenergic responses in the fingers of patients with idiopathic Raynaud's disease.

Methods: Clonidine HCl and phenylephrine HCl were administered through a brachial artery catheter while blood flow was measured by plethysmography in cooled and uncooled fingers.

Results: Cooling potentiated alpha 2-adrenergic vasoconstriction in the patients but depressed this response in the controls.

Local temperature modulates alpha 1- and alpha 2-adrenergic vasoconstriction in men.

Previous work in the canine saphenous vein has shown that cooling augments alpha 2- but not alpha 1-mediated contractile responses and that warming produces the opposite effects. Here we sought to determine whether these results occur in the human finger, a cutaneous vascular bed. Healthy men received brachial artery infusions of phenylephrine and clonidine with and without yohimbine while sympathetic tone was reduced by hearing the legs.

Plasma catecholamines during behavioral treatments for Raynaud's disease.

We have previously demonstrated that the vasospastic attacks of Raynaud's disease can be induced despite blockade of efferent digital nerves and that feedback-induced vasodilation is mediated through a non-neural, beta-adrenergic mechanism. Here, we sought to determine the role of sympathetic activity, as measured by plasma epinephrine and norepinephrine, during finger temperature feedback and autogenic training. Thirty-one female patients with idiopathic Raynaud's disease were randomly assigned to receive finger temperature feedback or autogenic training over 28 days.

Stress-induced desensitization of alpha 2-adrenergic receptors in human platelets.

Although agonist-induced desensitization of adrenergic receptors has been previously demonstrated, the regulation of adrenergic receptors during acute psychological stress has not been investigated in humans. We studied 30 first year medical students during final examination week and one month earlier. Platelet alpha 2 receptor binding was measured using 3H-yohimbine and leukocyte beta 2 receptor binding was measured with 125I-CYP (Iodocyanopindolol).