There is evidence that platelet activation in the coronary circulation may be important in the pathogenesis of myocardial ischemia. Since organic nitrate vasodilators are commonly used in coronary artery disease, we have studied the in vitro effects of these drugs on platelet function. Nitroglycerin, isosorbide dinitrate, and their biotransformation product, inorganic nitrite, inhibited platele...

External potassium ions have long been known as mediators of vasodilation of several vascular beds, including the coronary and cerebral circulations.1–6 Indeed, potassium ions have been viewed as communicators of the metabolic state of the cells that surround blood vessels. For example, release of potassium ions from neurons is communicated through glial cells to regulate cerebral artery diamet...

Long-term response to vasodilator therapy was assessed in six patients with PPH. Following an acute trial, each patient was restudied after (1) two months of drug administration, (2) one month of abstinence from therapy, and (3) an additional two months of therapy. Three of six patients had no long-term reduction of PVR after treatment; one showed a progressive increase. Of the three patients w...

Twenty-three children were admitted to a pediatric intensive care unit for scorpion envenomation with severe hypertension. The hypertension responded to analgesics and sedatives in 15 (65 percent) of the 23. The remaining eight children required specific antihypertensive therapy, and their condition promptly responded to intravenous hydralazine and sublingual nifedipine; rebound hypertension wa...

Microvascular functions have been shown to be sensitive to agents associated with changes in cyclic nucleotide levels. The central hypothesis of the current study was that one measure of capillary exchange capacity, hydraulic conductivity (Lp), would be elevated by agents shown to elevate cellular levels of cGMP. To evaluate the hypothesis, frog mesenteric capillary Lp was measured during lumin...

an 0.2 mg/min infusion ofTNG, and also after 1 mg/kg i.v. dipyridamole, ischemic flow was maintained in the face of a 20-30%o reduction in blood pressure. In this setting, nonischemic flow was unchanged during TNG and doubled after dipyridamole. With the addition of methoxamine in both dilator groups, blood pressure retumed to base line while flow to ischemic areas increased above base-line val...