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A nerve or an agent that causes blood vessel dilation.



one of a group of pharmacological agents that cause the smooth muscles of blood vessels to relax, which results in the widening of vascular lumens. Several groups of vasodilators are distinguished according to their mechanism of action and chemical structure.

Myotropic agents directly affect the muscular elements of the vascular wall, altering the metabolic processes and decreasing the tone of the elements. They include such purine derivatives as caffeine and theophylline, such isoquinoline derivatives as papaverine, drotaverine, salsoline, and such chromone derivatives as kellin.

Neurotropic agents exert a vasodilative effect through their influence on the neural regulation of vascular tone. They may have peripheral or central action. Those with peripheral action include adrenolytic agents, which block the adrenergic receptors of blood vessles (for example, phentolamine), and sympatholytics, which block the transmission of excitation from the endings of the sympathetic nerves that innervate blood vessels (for example, oktadin and ornid).

Other vasodilators include cholinomimetic and ganglion-blocking agents. The former, which include acetylcholine and carba-chol, facilitate the transmission of excitation from parasympathetic nerves to effector organs, including blood vessels. The latter, which include Tetamon (sympatektoman), Hexonium (esametina), and pentamin, impede the transmission of excitation in the sympathetic ganglia, resulting in a decrease in vascular tone. Derivatives of hydrazinophtalazine (for example, Apressin [Ap-resoline]), and of phenothiazine (for example, aminazine), affect the central regulation of vascular tone.

Some drugs have a mixed mechanism of action and may be centrally neurotropic and peripherally myotropic. These drugs include nitrites and nitrates (amyl nitrite, nitroglycerin, nitranol) and reserpine, which is an alkaloid isolated from the tropical plant rauwolfia. Reserpine weakens the central and peripheral adrenergic innervation of blood vessels, causing the vascular lumens to dilate and arterial pressure to decrease.

Vasodilators are used mainly in the treatment of ischemic heart disease, hypertension, and cerebrovascular disorders. They are also used in surgery to reduce bleeding (by lowering arterial pressure). Many vasodilators also have other pharmacological effects.


Kaverina, N. V. Farmakologiia koronarnogo krovoobrashcheniia. Moscow, 1968.
Mashkovskii, M. D. Lekarslvennyesredstva, 7th ed., part 1. Moscow, 1972.
Hoobler, S. W., and A. S. Dontas. “Drug Treatment of Hypertension.” Pharmacological Reviews, 1953, vol. 5, no. 2.


References in periodicals archive ?
Certain blood pressure lowering medications may have dangerous side effects as researchers have found a link between taking vasodilators and developing early-stage age-related macular degeneration (AMD) that could lead to vision loss and blindness, Medical journal reports.
Papaverine is a vasodilator with proven efficacy, and has been used clinically for many years.
To help clarify the relationship between AMD incidence and blood pressure lowering medications, including vasodilators, researchers from the University of Wisconsin School of Medicine and Public Health conducted a long-term population-based cohort study from 1988 to 2013 of nearly 5,000 residents of Beaver Dam, Wis.
However, which of these outcomes are true for the cerebral vasodilator effects of our DG decoction is unknown.
Keywords: Meniere's disease, endolymphatic hydrops, vertigo, hearing loss, tinnitus, diuretic therapy, vasodilator therapy.
Papaverine is the oldest vasodilator used in cardiac surgery to treat the internal mammary artery spasm.
vesica leaves, prepared as an aqueous extract, to be a potent endothelial dependant vasodilator acting via mediation of nitric oxide and cyclo-oxygenase products.
The guidelines point to a study of 557 patients with idiopathic PAH who underwent acute pulmonary vasodilator testing, with the 70 positive responders receiving long-term oral calcium channel blocker monotherapy.
NO is regarded as an extremely potent vasodilator, may have a role a primary signaling molecule in the early differentiation events of embryonic stem cells, acts to signal adaptive responses of the cardiopulmonary vasculature, enhances endothelial barrier functions, NO has potential application as a topical antimicrobial agent, regulates vascular tone, neurotransmission, the regulation of cell death.
1]R leads to vasoconstriction rather than the loss of vasodilator activity as a result of inhibition of NO production.
Femprox(r) incorporates NexMed's NexACT transdermal penetration enhancing technology with the vasodilator, alprostadil.
A comparison of the 2 inotropic drugs administered to 36 heart transplant patients at the time of hospitalization (dobutamine for a mean of 50 days, milrinone for a mean of 63 days) found no intergroup differences in right heart hemodynamics, incidence of death, need for additional vasodilator or inotropic therapy, or need for pretransplant mechanical cardiac support.