Vasodilating effects

Phiorog1iicino1-3,5-dimethyl-1-(2-amino-3-hydroxyhutyryl)ether is characterized by antiarrhythmic activity (176). 2,4-Diacylphloroglucinols were patented as compounds with pronounced anthelmintic activity (177). Phloroglucinol mono- and di-(2-chloroethyl) ethers have antispasmodic or tranquilizing activities (178). 2-(3,5-DiaLkoxyphenoxy)ethylamines have antispasmodic, choloretic, sedative, and vasodilating effects (179). 

Nicorandil. Nicorandil is a potassium channel opener that can lower blood pressure 21, 20, and 29 mm Hg after single oral doses of 10, 20, and 30 mg, respectively (250). There are no significant changes ia heart rate. Headache is the primary side effect. Nicorandil has potent coronary vasodilator effects. It causes sustained vasodilation of arteriolar resistance and venous capacitance blood vessels, thus reduciag cardiac preload and aftedoad. 

Phentolamine (Regitine) is used for its vasodilating effect on peripheral blood vessels and therefore may be beneficial in the treatment of hypertension caused by... 

Acetylchohne is a vasodilator that acts by causing relaxation of the smooth muscle of blood vessels. However, it does not act directly on smooth muscle. A key observation was that if endothefial cells were stripped away from underlying smooth muscle cells, acetylcholine no longer exerted its vasodilator effect. This finding indicated that vasodilators such as acetylcholine initially interact with the endothelial cells of small blood vessels via receptors. The receptors are coupled to the phos-phoinositide cycle, leading to the intracellular release of... 

Resistance in the arterioles of the working muscles is regulated locally. As discussed previously, active hyperemia results in production of several factors that cause metabolic vasodilation. Exercising muscles generate COz, H+ and K+ ions, heat, and adenosine. The vasodilator effect of these locally produced substances overrides the vasoconstrictor effect of the sympathetic system in the muscle. As a result, local vascular resistance is decreased. The combination of increased driving pressure and decreased local vascular resistance causes an increase in blood flow to the working muscles. 

Thus GPR109A mediates the niacin-induced antilipolysis effect in adipocytes and vasodilation effect in skin. This discovery represents significant progress in understanding the mechanism of action for niacin, but also poses a challenge to develop a therapeutic agent to separate the lipid and vasodilation effects. 

There are several mechanisms involved in the vasodilator effect of flavonoids. The main mechanism seems to be related to the inhibition of protein kinase C or some of the processes activated by this protein. The inhibition of other protein kinases and cyclic nucleotide phosphodiesterase activity and blockage of calcium entry can also contribute to this effect to a greater or lesser extent (Alvarez Castro and Orallo, 2003 Herrera and others 1996). Certain flavonoids, like the flavonol myricetin, have a two-phase action on blood vessels vasoconstrictor in lowest active concentrations and vasodilator in higher concentrations (Alvarez Castro and Orallo, 2003). 

Nicotinic acid in large doses used to treat hyperlipoproteinemia causes a cutaneous flush. The vasodilator) effect is due to... 

Milrinone is a bipyridine derivative that inhibits phosphodiesterase 111 and produces positive inotropic and arterial and venous vasodilating effects hence, milrinone has been referred to as an inodilator. It has supplanted use of amrinone, which has a higher rate of thrombocytopenia. 

Dihydropyridines cause a baroreceptor-mediated reflex increase in heart rate because of their potent peripheral vasodilating effects. Dihydropyridines do not decrease AV node conduction and are not effective for treating supraventricular tachyarrhythmias. 

Needleman, P., Blehm, D J., Rotskoff, K. S., Relationship between glutathione-dependent denitration and the vasodilator effectiveness of organic nitrates. J. Pharmacol. Exp. Then 237 (1969), p. 296-288... 

The hypothesis that HNO is not involved during NO-release from sydnonimines was confirmed by the study of NO-release from C78-0652 109, the dimethyl derivative of SIN-1A (Scheme 6.19). This product closely resembles SIN-1A in its biological and pharmacological behavior, showing a clear NO-dependent vasodilating effect on guinea pig pulmonary arteries and hypotensive action in anesthetized and conscious dog models [105]. 

ACE is bound to the luminal surface of vascular endothelium occurring in particularly high concentration in the pulmonary capillary bed. The product of the ACE reaction, angiotensin II, is a potent vasoconstrictor by its action on vascular smooth muscle cells allowing calcium influx and opposing the vasodilator effect of... 

Nitric oxide Ginsenosides enhance nitric oxide synthesis, with effects in the endothelium of the lungs, heart, and kidneys and in the corpus cavernosum (Kim H et al. 1992 Ko et al. 1996). This is a potential mechanism of ginseng-associated vasodilation. Effects on neuronal nitric oxide have not been specifically investigated. 

Most of the cardiotonic pyridazine derivatives discussed in the preceding chapter also exhibit vasodilator effects. In addition, various dihydropyrida-zine derivatives like (52), structurally closely related to calcium-antagonistic Hantzsch-type dihydroypyridines, have been patented as coronary vasodilators [169-171]. Another type of pyridazine analogue of the previously mentioned dihydropyridines, namely compounds of type (53), in which the aryl substituent at C-4 is represented by a pyridazine nucleus, has been claimed in a patent [172]. Quite recently, pyridazinyldihydropyridine-3,5-dicarboxyl-ates (54,55) have been prepared in Austria [173]. 

Tanaka M, Matsni T, Ushida Y, Matsumoto K. (2006) Vasodilating effect of di-peptides in thoracic aortas from spontaneously hypertensive rats. Biosci Biotechnol Biochem 70 2292-2295. 

Tanaka M, Toknyasn M, Matsui T, Matsumoto K. (2008) Endothelium-independent vasodilation effect of di- and tri-peptides in thoracic aorta of Spragne-Dawley rats. Life Sci 82 869-875. 

Miguel M, Alvarez Y, Lopez-Fandino R, Alonso JM, Salaices M. (2007) Vasodilator effects of peptides derived from egg white proteins. Regul Pept 140 131-135. 

Altered vascular responses When P2-receptors are blocked, the vasodilating effect of epinephrine is abolished, leaving the a-receptor-mediated vasoconstriction unaffected peripheral blood flow i - cold hands and feet . 

These vasodilator effects produce hemodynamic consequences that can be put to therapeutic use. Due to a decrease in both venous return (preload) and arterial afterload, cardiac work is decreased (p. 308). As a result, the cardiac oxygen balance improves. Spasmodic constriction of larger coronary vessels (coronary spasm) is prevented. 

In human volunteers significant lung vasodilator effects have been observed at 10-40 ppm. Studies indicate that nitric oxide stimulates guanylate cyclase, which leads to smooth muscle relaxation and vasodilation. Because... 

Pharmacology Niacinamide is synonymous with nicotinamide, 3-pyridine carboxamide, and nicotinic acid amide. Niacinamide is the amide of nicotinic acid (niacin, vitamin B3). Although nicotinic acid and nicotinamide function identically as vitamins, their pharmacologic effects differ. Nicotinamide does not have the hypolipidemic or vasodilating effects characteristic of niacin (nicotinic acid). 

Pharmacology Hydralazine exerts a peripheral vasodilating effect through a direct relaxation of vascular smooth muscle. 

Other pharmacological effects - Clinical effects, in addition to antidepressant effects, include sedation, anticholinergic effects, mild peripheral vasodilator effects and possible quinidine-like actions. 

O -Adrenoceptor antagonists (o -blockers) are competitive inhibitors at the level of Q -adrenoceptors. These receptors are found in many organs and tissues, but their predominant functional importance is to mediate the vasoconstrictor effects of endogenous catecholamines (noradrenaline, adrenaline) released from the sympathetic nerve endings. Conversely, Q -adrenoceptor antagonism by means of an a-blocker will inhibit this constrictor activity and hence cause vasodilatation. This vasodilator effect occurs in both resistance vessels (arterioles) and capacitance vessels (veins), since a-adrenoceptors are present in both types of vascular structures. Accordingly, both cardiac afterload and preload will be lowered, in particular when elevated. 

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