Interactions among inflammatory mediators on edema formation in the canine forelimb.

Prostaglandin E1, 4 microgram/min, infused locally intra-arterially (ia) for 60 minutes into forelimbs perfused at constant pump controlled inflow produced decreases in perfusion pressure, increases in lymph total protein concentration (approximately equal to g/100 ml), and small increases in weight (23 g) owing to edema formation. Histamine, 16 microgram base/min, or bradykinin, 10 microgram base/min, infused locally ia for 60 minutes produced large increases in lymph flow, lymph total protein concentration, total protein transport, and weight (70 g and 130 g, respectively). However, the local ia infusion of prostaglandin E1, 4 microgram/min, together with histamine, 16 microgram base/min, or bradykinin, 10 microgram base/min, produced weight increases of 180 g and 236 g, respectively, and the rate of weight gain during the combination infusions greatly exceeded that produced by infusions of histamine or bradykinin alone.

Facilitation of cardiac sympathetic function by angiotensin II: role of presynaptic angiotensin receptors.

Intravenous infusion of two separate doses of angiotensin II in pentobarbital-anesthetized, desipramine-treated animals produced dose-related increases in arterial blood pressure and caused significant potentiation of the cardioacceleration observed during the stimulation of the right postganglionic cardiac sympathetic nerve fibers. Positive chronotropic effects of intravenous norepinephrine were not altered during angiotensin II infusion. Prior administration of Saralasin, an angiotensin receptor antagonist, caused significant attenuation of the pressor action of angiotensin II, and also significantly antagonized the facilitatory effect of angiotensin II on sympathetic transmission to the myocardium.