We use cookies to create the best experience for you. Keep on browsing if you are OK with that, or find out how to manage cookies.
Nobody downloaded yet

Why are L-type calcium channels valid targets for the treatment of hypertension - Essay Example

Comments (0)
Hypertension is a common problem world wide with devastating complications. Several classes of antihypertensives are available for use and they include ACE inhibitors, thiazide diuretics, beta blockers, angiotensin II receptor antagonists and calcium channel blockers…
Download full paper

Extract of sample
Why are L-type calcium channels valid targets for the treatment of hypertension

Download file to see previous pages... Hypertension is a common problem world wide with devastating complications. Several classes of antihypertensives are available for use and they include ACE inhibitors, thiazide diuretics, beta blockers, angiotensin II receptor antagonists and calcium channel blockers. Which is the most ideal antihypertensive agent has been the subject of several large studies and to date, no ideal antihypertensive agent has been declared. The main goal of antihypertensive therapy is to decrease the risk of endpoints of hypertension, namely stroke, heart failure and myocardial ischemia. The type of medication administered depends on the age of the person and comorbid conditions. Other influencing factors include cost of medicines and tolerance to medications. For several years, L-calcium channel blockers have been the first line antihypertensive drugs for hypertensive patients (Klabunde, 2008). Calcium channel blockers are those drugs which prevent the entry of calcium into the cells of the heart and the blood vessels. By doing so, the muscles of the heart and blood vessels relax, resulting in dilatation of blood vessels and lowering of blood pressure. Some calcium channel blockers cause decrease the heart rate, thus further reducing the blood pressure. Calcium channel blockers not only reduce blood pressure, but also relieve angina and irregular heart beat. The calcium channel blockers which are currently approved bind to the L-type calcium channels that are located on the cardiac myocytes, vascular smooth muscle and cardiac nodal tissue, the atrioventricular and sinoatrial nodes. The channels regulate the influx of calcium into the muscle cells and in turn stimulate the contraction of the smooth muscles and the cardiac myocyte. In the nodal tissues of the heart, the L-type channels have major role to play in the pacemaker currents and in the phase 0 of action potentials. Thus, blocking of calcium entry into the cells causes vasodilation, negative ionotropy, negative dromotropy at the atrioventricular node, and negative chronotropy (Klabunde, 2008). Calcium channels are voltage dependent and opening of these channels permits influx of the calcium ions across the plasma membrane, thus triggering various physiological processes. The channels are distributed widely in the cardiovascular system, constituting main routes for entry of the calcium ions essential for excitation and contraction. In this regard, as of now, ten unique alpha-1 subunits have been identified and these are groups in 3 families: CaV1, CaV2, and CaV3. These encode the low-voltage–activated T-type and the high-voltage–activated L-, N-, P/Q- and R-type Ca2+ channels (Ge and Ren, 2009). The most common of these are the L-type and they are abundant in the peripheral vasculature and heart, constituting preferred target for initial calcium channel antagonists in antihypertensive treatment. T-channels are present in various cells like cardiomyocytes, neurons, endocrine cells and vascular smooth muscle cells. They have a role in several physiological processes (Ge and Ren, 2009). There is some evidence that T-channel blockade also is useful in the management of hypertension. The drugs developed for this purpose are dihydropyridines like benidipine, efonidipine, nilvadipine, manidipine and benzimidazole mibefradil (Ge and Ren, 2009). These drugs have vasodilatory properties similar to L-channel blockers and some of them may antagonise both L-channels and T-channels. However, there is yet uncertainity about the exact role of T-channel blockers in controlling vascular tone and decreasing hypertension (Toba et al, 2011). There are basically 3 classes of calcium channel blockers and they are: 1. Dihydropyridines: These are selective to smooth muscles of the blood vessels. Hence, they are mainly used to decrease systemic vascular resistance and arterial pressure. They are also primarily used to treat hypertension. They are not useful in the treatment of angina because reflex cardiac ...Download file to see next pagesRead More
Comments (0)
Click to create a comment
Normal levels of BP defined by Joint National Committee 7 (JNC 7) state values of 120 mm of Hg and 80 mm of Hg for systolic and diastolic respectively (Chobanian et al. 2003). The American Heart Association (AHA) defines hypertension as systolic and diastolic BP higher than 140 and 90 mm of Hg respectively (Carretero & Oparil 2000).
4 Pages(1000 words)Essay
Blood pressure is considered abnormally high if it exceeds the normal level of 120/80. The 120 represents the systolic/peak measurement of blood pressure while the 80 stands for the diastolic/minimum blood pressure measurement in the arteries. If the blood pressure falls in the 120/80-139/89, a person is said to be in a pre-hypertension state, implying an increased risk of developing hypertension.
8 Pages(2000 words)Research Paper
Hypertension is a symptomless condition, though the below could indirectly point towards the condition: a. Blood spots observed in the eyes b. Dizziness c. Facial flushing (www.heart.org) B. The Main Causes of Hypertension The principle causes include genetics and lifestyle (www.heart.org).
4 Pages(1000 words)Essay
Hypertension is dangerous. Even moderate elevation of arterial blood pressure leads to shortened life expectancy. At severely high pressures, defined as mean arterial pressures 50% or more above average, a person can expect to live no more than a few years unless appropriately treated.
6 Pages(1500 words)Essay
Calcium as Second Messengers
Binding of a ligand to a single receptor at the cell surface may end up causing massive changes in the biochemical activities within the cell (Kimball, 2006). There are three types of second messengers: cyclic nucleotides like cAMP (cyclic adenosine monophosphate); IP3 ( inositol triphosphate) and DAG ( diacylglycerol); and Calcium ions.
4 Pages(1000 words)Essay
Screening for novel peptides that block T-type calcium channels
Other calmodulin-mediated enzymes include phosphatases, cyclases, esterases, and ion channels. Cytoplasmic calcium ions also contribute into inducing protein and DNA synthesis, and nuclear transport, thus trapping the cells in its quiescent state of cell
4 Pages(1000 words)Essay
Type 1 diabetes, Hypertension
Although the patient’s blood sugar is already within relatively normal levels, it is still important to maintain such levels until such time when his blood pressure would normalize and his other symptoms – his weakness and lack of energy would
4 Pages(1000 words)Essay
L-Dopa As A Treatment for Catatonia
Oliver Sacks, initially presenting an overview of the condition and the drug, proceeding to a discussion of Dr. Sacks’ experiment. During the early 1900s, an
2 Pages(500 words)Essay
Effects of steroids on calcium activated potassium channels and secretion of LH and FSH in Atlantic cod (Gadus morhua)
The pituitary gland is comprised of two main compartments, that is, the neural (neurohypophysis) and non-neural (adenohypophysis). LH and FSH gonadotropes are located on the adenohypophysis compartment and there is empirical
11 Pages(2750 words)Essay
Hypertension is a huge problem in the USA the world general. The number of recorded deaths that were related to hypertension in 2011 in the USA was 27,853 (Deaths: Final Data for 2011, 2011). Hypertension cases are grouped into two: primary hypertension and secondary
5 Pages(1250 words)Essay
Let us find you another Essay on topic Why are L-type calcium channels valid targets for the treatment of hypertension for FREE!
Contact us:
Contact Us Now
FREE Mobile Apps:
  • About StudentShare
  • Testimonials
  • FAQ
  • Blog
  • Free Essays
  • New Essays
  • Essays
  • The Newest Essay Topics
  • Index samples by all dates
Join us:
Contact Us