Antioxidant effects and the therapeutic mode of action of calcium channel blockers in hypertension and atherosclerosis

Abstract

Drugs currently known as calcium channel blockers (CCB) were initially called calcium antagonists because of their ability to inhibit calcium-evoked contractions in depolarized smooth muscles. Blocking the entry of calcium reduces the active tone of vascular smooth muscle and produces vasodilatation. This pharmacological property has been the basis for the use of CCBs in the management of hypertension and coronary heart disease. A major question is whether drugs reducing blood pressure have other effects that help prevent the main complications of hypertension, such as atherosclerosis, stroke, peripheral arterial disease, heart failure and end-state renal disease. Experimental studies that focus on this question are reviewed in the present paper.

Contraction by Ca2+ Influx via the L-Type Ca2+ Channel Voltage Window in Mouse Aortic Segments is Modulated by Nitric Oxide

“…They reduce blood pressure more effectively in hypertensive than in normotensive subjects (Leonetti et al, 1982) and they inhibit L-type Ca 2+ influx more effectively in vascular tissue than in heart (Godfraind et al, 1984;Godfraind, 2005;Striessnig et al, 1998). Several attempts have been made to explain these unique features.…”

“…In hypertension, there is an increase of reactivity to vasoconstrictors, which is not only due to a higher number of L-type Ca 2+ channels (Godfraind, 2005;Pesic et al, 2004;Pratt et al, 2002), but also to depolarization of the resting potential of hypertensive VSMCs (Morel & Godfraind, 1994;Pesic et al, 2004). Depolarization leads to an increased proportion L-type Ca 2+ channels in the inactivated state, which according to the "modulated receptor theory" may have higher affinity to CaBs than channels in the resting state (Bean et al, 1986;Godfraind, 2005;Morel & Godfraind, 1987). Cardiac muscle cells are hyperpolarized with respect to VSMC and hence less susceptible to block by CaBs.…”

Effect of Tulbaghia violacea on the blood pressure and heart rate in male spontaneously hypertensive Wistar rats

“…The agents in groups (a), (b), and (c) are used in the management of HTN; while the last group is used in treating neurological disorders such as migraines, neuropathic pain, and dementia. A major feature of the long-term action of CCBs is the prevention of the structural changes induced by HTN in heart and arteries (Mason, 2002;Godfraind, 2005).…”

Determination of antioxidant, radical scavenging activity and total phenolic compounds of Artocarpus heterophyllus (Jackfuit) seeds extracts

“…Apart from their role in the diseased conditions in the body, ROS are also known to have a role in the spoilage of food by the autoxidation of lipids, the enzymatic oxidation, during storage and processing in fats, oils and fat-containing foods (Matthaus, 2002). Antioxidants are defined as substances present at low concentration, relative to the oxidizable substrate, which significantly delay or prevent oxidation of substrate (Godfraind, 2005). In the body, antioxidants act as free radical scavengers and thus protect cells from being exposed to free radicals and further cellular damage.…”