Vasodilatory activity

The rate of removal of the local anesthetic from the site of injection also affects its profile. AH local anesthetic agents possess some vasodilatory activity at clinically useful concentrations. Agents which are more potent in this regard tend to be absorbed more rapidly by the vasculature. They are less potent anesthetics and have shorter durations than those having lower vasodilatory activity. A comparison of potency, onset, and duration as a function of physiochemical properties is presented in Table 4. 

A 1,4-dihydropyridine having coronary vasodilatory activity and, therefore, intended for relief of the intense chest pains of angina pectoris is nifedipine (34). Using a portion of the classical Hantzsch pyridine synthesis, condensation of two moles of... 

O-acyl derivatives thereof have shown potent vasodilatory activity [8]. A number of other hetisine alkaloids have shown diverse biological activities. These include nominine [9] (1) (local anesthetic, anti-inflammatory, and antiarrhythmic), hetisine [9a] (4) (hypotensive), ignavine [10] (5) (analgesic, anti-inflammatory, antipyretic, sedative, antidiuretic), zeravshanisine [9a] (8) (antiarrhythmic and local anesthetic), and tadzhaconine [9a, 11], (9) (antiarrhythmic) (Chart 1.3). 

After 2- days of repeated NG exposure, tolerance to the vasodilatory activity occurs, probably as a result of compensatory vasoconstriction. Tolerance may be lost during periods without NG exposure, such as weekends and holidays. Recent smdies have suggested that tolerance may be mediated by a mitochondrial aldehyde dehydrogenase that catalyzes the formation of 1,2-glyceryl dinitrate and nitrite from NG, leading to production of cGMP and relaxation of vascular smooth muscle. ... 

Other nitrosyl compounds such as, K[NOBr5lr], K2[NOCLsRu] and [NO(NH3)sRu]Cl3, have also shown vasodilatory activity, presumably by releasing NO, but are too toxic for clinical use. A nitro complex, [Cl(02NXbpy)2Ru], which probably releases NOJ, exhibited higher activity than sodium nitrite [38]. 

Ignarro LJ. Experimental evidences of nitric oxide-dependent vasodilatory activity of nebivolol, a third-generation beta-blocker. Blood Press Suppl. 2004 ... 

Manidipine (Fig. 7.11) is a nifedipine analogue which shows a potent and selective calcium antagonist activity that translates into a potent antihypertensive and coronary vasodilatory activity. Manidipine shows some selectivity towards the renal vasculature, making it particularly useful for the treatment of renovascular hypertension. 

In conclusion, all dihydropyridines show a potent calcium channel antagonist activity, which is in turn translated into direct arteriolar spasmolytic effect that results in a beneficial vasodilatory activity. This is useful in some cardiovascular diseases, such as hypertension and angina, in which the peripheral resistances are raised due to increased calcium entry into the cells. Many analogues of nifedipine have been synthesized and introduced into the market, and each of these presents some common features and some peculiar differences. In particular ... 

In vivo, lacidipine -when administered orally - was found to be an effective and potent antihypertensive agent in different animal models, including SHR (ED25 = 0.5 mg kg-1, per os) and renally hypertensive dogs (ED25 = 0.004 mg kg-1, i.v.) with a sustained duration of action [11,12]. Lacidipine was also found to possess coronary and cerebral vasodilatory activity [13]. 

From a case in which there was positive dechallenge and rechallenge it has been concluded that edema of the lower limbs can be an adverse effect of ritonavir in some HIV-positive patients (11). The authors suspected a relation to the drug s vasodilatory activity. However, it should also be borne in mind that ritonavir has caused reversible renal insufficiency, which should be looked for in any patient who develops edematous changes. 

Moxisylyte is an alpha-adrenoceptor antagonist with vasodilatory activity (1). It is used orally in the treatment of peripheral vascular disease and by intracavernosal injection in erectile dysfunction. 

A pharmacological study on conkurchine hydrochloride demonstrated a hypotensive and vasodilatory activity of this alkaloid 134). 

The antagonistic action of tolazoline is relatively weak, but its histaminc-like and acclylcholinc-like agonistic actions probably conlribule to its vasodilatory activity. Its his-laminc-like effects include stimulation of ga.stric acid secretion, rendering it inappropriate for administration to patients who have gastric or peptic ulcers. Il has been used to treat Raynaud s syndrome and other conditions involving peripheral vasospasm. Tolazoline is available in an injectable form and is indicated for use in persi.stent pulmonary hypertension of the newborn when supportive measures are not successful. 

FIGURE 10.15 Effects of adenosine receptor agonist 2-chloroadeno-sine on vascular perfusion pressure of isolated perfused rat kidneys. Minor effects seen in untreated kidneys (filled circles) and pronounced vasoconstriction while vasodilatation in kidneys coperfused with subthreshold concentrations of a-adrenoceptor vasoconstrictor methoxamine and vasodilatory activation of adenylyl cyclase with forskolin (open circles). Redrawn from [49]. 

Vasorelaxant effect of three flavonoids from Satujera obovata was studied, these were luteolin (6), eriodictyol (112) and naringenin (182) [130], as well as vasodilatory activity [131]. 

Norverapamil has negligible actions on cardiac conduction, but has potent vasodilatory activity. 

Felodipine would be useful in antianginal therapy due to its coronary vasodilatory actions, but its potent vasodilatory activity elicits a reflex tachycardia that increases myocardial oxygen consumption. 

Yes. The drug is extensively metabolized, producing both inactive metabolites and the active metabolite desacetyldiltiazem, which has coronary vasodilatory activity. 

Not in the strict sense. These drugs primarily dilate veins, more than arteries. Some drugs in the class, such as sodium nitroprusside, also have significant vasodilatory activity. 

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