Previous investigations have allowed for stratification of patients with postural tachycardia syndrome (POTS) on the basis of peripheral blood flow. One such subset, comprising "normal-flow POTS" patients, is characterized by normal peripheral resistance and blood volume in the supine position but thoracic hypovolemia and splanchnic blood pooling in the upright position. We studied 32 consecuti...

We hypothesized that alpha(1)-adrenoceptor stimulation of cardiac myocytes results in the production of an endothelin (ET)-releasing factor that stimulates the coronary vasculature to release ET and, by manipulating the redox state of cardiac and vascular cells, may influence the extent of alpha(1)-adrenergic-ET-1 vasoconstriction. Dihydroethidium (DHE) and dichlorodihydrofluorescein (DCF) inte...

OBJECTIVE Sphingosylphosphorylcholine (SPC) is an important lipid mediator that has been implicated in vascular disease. As it has not been studied in the pulmonary circulation, we examined its mechanisms of action in rat small intrapulmonary arteries (IPA). METHODS IPA were mounted on a myograph for recording tension and intracellular Ca2+ concentration ([Ca2+]i). Ca2+ sensitisation was exam...

Acute hypoxia induces pulmonary vasoconstriction and chronic hypoxia causes structural changes of the pulmonary vasculature including arterial medial hypertrophy. Electro- and pharmacomechanical mechanisms are involved in regulating pulmonary vasomotor tone, whereas intracellular Ca(2+) serves as an important signal in regulating contraction and proliferation of pulmonary artery smooth muscle c...

JUST, T.P., I.R. COOPER, and D.S. DELOREY. Sympathetic vasoconstriction in skeletal muscle: adaptations to exercise training. Exerc. Sport Sci. Rev., Vol. 44, No. 4, pp. 137–143, 2016. Sympathetic vasoconstriction in the skeletal muscle vascular bed is essential for the regulation of vascular resistance and therefore control of blood pressure and muscle blood flow at rest and during exercise. I...