Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-type calcium channel antagonist is clinically used for treatment of cardiovascular diseases such as angina, hypertension and arrhythmia. Recent large clinical trials indicated that calcium antagonist is effective in the prevention of cardiovascular event as well as the treatment of hypertension. Recently, calcium antagonists, not stimulating sympathetic nerve activity, have been newly developed. In the future, clinical application of N-type or T-type calcium antagonist are expected.
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PMID:[Perspective of calcium antagonist]. 1563 76

We encountered a 91-year-old woman with atrial fibrillation complicating bradycardia while she was receiving therapy with an L/N-type calcium channel blocker, cilnidipine, for hypertension, which is an unusual observation for the dihydropyridine class of calcium channel blockers. Therefore, we compared the dromotropic effect of cilnidipine with that of an L-type calcium channel blocker, nicardipine, which has a similar hypotensive activity. The canine isolated, blood-perfused atrioventricular node preparation was used. Cilnidipine as well as nicardipine slowed atrioventricular nodal conduction in a dose-related manner. However, the dromotropic action of cilnidipine was about five times less potent than that of nicardipine. These experimental results may suggest that we experienced an atypical clinical event of cilnidipine in a very old woman; otherwise one can speculate that the N-type calcium channel inhibitory component of cilnidipine might have played a role in exerting the negative dromotropic effect in this patient.
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PMID:Comparison of the direct negative dromotropic effect of a new calcium channel blocker, cilnidipine, with that of nicardipine. 1591 7

1. The present study investigates the vasoselectivity of lercanidipine (LER), a 1,4-dihydropyridine calcium channel blocker, compared with amlodipine (AML) and nifedipine (NIF) in human cardiovascular tissue. Experiments were performed either in human left ventricular failing myocardium (orthotopic heart transplants) or in isolated right atrial trabeculae and isolated vessel preparations of arteria mammaria obtained from patients undergoing aortocoronary bypass operation. 2. The obtained rank order for the L-type Ca2+ channel affinity in human tissue was LER > NIF >or= AML. Lercanidipine had the lowest negative inotropic efficacy (1 micromol/L LER: 60.3% basal < AML: 79.1% basal < NIF: 92.4 basal) and potency (IC50 NIF: 3.5 nmol/L < AML: 48 nmol/L < Ler: 127 nmol/L) in right atrial trabeculae. 3. The vasorelaxant potency of LER (IC50 0.5 nmol/L) and AML (IC50 0.8 nmol/L) was similar and significantly increased compared with that of NIF (IC50 5.9 nmol/L) in arteria mammaria preparations of the very same patients. 4. The following rank order was obtained for vasoselectivity: LER (260) < AML (60) < NIF (0.6). 5. The pharmacological effects of LER and AML were still present 2 h after drug washout. 3. Lercanidipine is characterized by a high vasoselectivity and a prolonged interaction with the L-type calcium channel in human cardiovascular tissue This may be advantageous, especially in the treatment of patients with arterial hypertension.
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PMID:Increased vascular selectivity and prolonged pharmacological efficacy of the L-type Ca2+ channel antagonist lercanidipine in human cardiovascular tissue. 1617 26

Recent studies provide evidence that aldosterone (Aldo) accelerates hypertension, proteinuria and glomerulosclerosis in animal models of chronic renal failure. Although the underlying mechanisms are not well defined, Aldo may exert these deleterious renal effects by elevating renal vascular resistance (RVR) and glomerular capillary pressure (P(GC)). To test this possibility, we studied the action of Aldo on rabbit afferent (Af-) and efferent arterioles (Ef-Arts), crucial vascular segments to the control of glomerular hemodynamics. Aldo caused rapid (within 5 min) constriction in both arterioles. The constriction was not affected by spironolactone but was reproduced by membrane-impermeable albumin-conjugated Aldo, suggesting that vasoconstrictor actions are non-genomic. This notion was further supported by the finding that neither actinomycin D nor cycloheximide had effect. The vasoconstrictor action of Aldo on Af-Arts was inhibited by nifedipine (L-type calcium channel blocker), whereas that on Ef-Arts was inhibited by efonidipine (both L- and T-type calcium channel blocker) but not nifedipine. Disrupting the endothelium or nitric oxide (NO) synthesis inhibition augmented the vasoconstriction in Af-Arts, demonstrating that endothelium-derived NO modulates the vasoconstrictor actions of Aldo. Thus, Aldo causes non-genomic vasoconstriction via calcium mobilization thorough L- or T-type calcium channels in Af- or Ef-Arts, respectively. These vasoconstrictor actions on the glomerular microcirculation may play an important role in the pathophysiology and progression of renal diseases by elevating RVR and P(GC), especially when endothelium functions are impaired. In addition to our study, this review describes recent findings on the rapid cardiovascular actions of Aldo, with a particular attention to the renal hemodynamics.
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PMID:Aldosterone and the kidney: rapid regulation of renal microcirculation. 1628 72

Calcium channel antagonists have a well-established role in the management of cardiovascular diseases. L-type calcium channels in vascular cells are a key therapeutic target in hypertension and are the preferred molecular target of the initial calcium channel antagonists. However, third-generation dihydropyridine (DHP) calcium channel antagonists, including manidipine, nilvadipine, benidipine and efonidipine, appear to have effects in addition to blockade of the L-type calcium channel. Voltage-gated calcium channels are widely expressed throughout the cardiovascular system. They constitute the main route for calcium entry, essential for the maintenance of contraction. Cardiac and vascular cells predominantly express L-type calcium channels. More recently, T-type channels have been discovered, and there is emerging evidence of their significance in the regulation of arterial resistance. A lack of functional expression of L-type channels in renal efferent arterioles may be consistent with an important role of T-type channels in the regulation of efferent arteriolar tone. Although the exact role of T-type calcium channels in vascular beds remains to be determined, they could be associated with gene-activated cell replication and growth during pathology. The three major classes of calcium channel antagonists are chemically distinct, and exhibit different functional effects depending on their biophysical, conformation-dependent interactions with the L-type calcium channel. The DHPs are more potent vasodilators, and generally have less cardiodepressant activity than representatives of other classes of calcium channel antagonist such as diltiazem (a phenylalkylamine) and verapamil (a benzothiazepine). In contrast to older calcium channel antagonists, the newer DHPs, manidipine, nilvadipine, benidipine and efonidipine, dilate not only afferent but also efferent renal arterioles, a potentially beneficial effect that may improve glomerular hypertension and provide renoprotection. The underlying mechanisms for the heterogenous effects of calcium channel antagonists in the renal microvasculature are unclear. A credible hypothesis suggests a contribution of T-type calcium channels to efferent arteriolar tone, and that manidipine, nilvadipine and efonidipine inhibit both L and T-type channels. However, other mechanisms, including an effect on neuronal P/Q-type calcium channels (recently detected in arterioles), the microheterogeneity of vascular beds, and other types of calcium influx may also play a role. This article presents recent data about the expression and physiological role of calcium channels in arteries and the molecular targets of the calcium channel antagonists, particularly those exhibiting distinct renovascular effects.
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PMID:Vascular effects of calcium channel antagonists: new evidence. 1639 57

Voltage-dependent Ca2+ channels Cav1.2 (L type) and Cav2.1 (P/Q type) are expressed in vascular smooth muscle cells (VSMCs) and are important for the contraction of renal resistance vessels. In the present study we examined whether native renal VSMCs coexpress L-, P-, and Q-type Ca2+ currents. The expression of both Cav2.1a (P-type) and Cav2.1b (Q-type) mRNA was demonstrated by RT-PCR in renal preglomerular vessels from rats and mice. Immunolabeling was performed on A7r5 cells, renal cryosections, and freshly isolated renal VSMCs with anti-Cav1.2 and anti-Cav2.1 antibodies. Conventional and confocal microscopy revealed expression of both channels in all of the smooth muscle cells. Whole-cell patch clamp on single preglomerular VSMCs from mice showed L-, P-, and Q-type currents. Blockade of the L-type currents by calciseptine (20 nmol/L) inhibited 35.6+/-3.9% of the voltage-dependent Ca2+ current, and blocking P-type currents (omega-agatoxin IVA 10 nmol/L) led to 20.2+/-3.0% inhibition, whereas 300 nmol/L of omega agatoxin IVA (blocking P/Q-type) inhibited 45.0+/-7.3%. In rat aortic smooth muscle cells (A7r5), blockade of L-type channels resulted in 28.5+/-6.1% inhibition, simultaneous blockade of L-type and P-type channels inhibited 58.0+/-11.8%, and simultaneous inhibition of L-, P-, and Q-type channels led to blockade (88.7+/-5.6%) of the Ca2+ current. We conclude that aortic and renal preglomerular smooth muscle cells express L-, P-, and Q-type voltage-dependent Ca2+ channels in the rat and mouse.
Hypertension 2006 Apr
PMID:Coexpression of voltage-dependent calcium channels Cav1.2, 2.1a, and 2.1b in vascular myocytes. 1650 11

Small-molecule inhibitors of protein function are powerful tools for biological analysis and can lead to the development of new drugs. However, a major bottleneck in generating useful small-molecule tools is target identification. Here we show that Caenorhabditis elegans can provide a platform for both the discovery of new bioactive compounds and target identification. We screened 14,100 small molecules for bioactivity in wild-type worms and identified 308 compounds that induce a variety of phenotypes. One compound that we named nemadipine-A induces marked defects in morphology and egg-laying. Nemadipine-A resembles a class of widely prescribed anti-hypertension drugs called the 1,4-dihydropyridines (DHPs) that antagonize the alpha1-subunit of L-type calcium channels. Through a genetic suppressor screen, we identified egl-19 as the sole candidate target of nemadipine-A, a conclusion that is supported by several additional lines of evidence. egl-19 encodes the only L-type calcium channel alpha1-subunit in the C. elegans genome. We show that nemadipine-A can also antagonize vertebrate L-type calcium channels, demonstrating that worms and vertebrates share the orthologous protein target. Conversely, FDA-approved DHPs fail to elicit robust phenotypes, making nemadipine-A a unique tool to screen for genetic interactions with this important class of drugs. Finally, we demonstrate the utility of nemadipine-A by using it to reveal redundancy among three calcium channels in the egg-laying circuit. Our study demonstrates that C. elegans enables rapid identification of new small-molecule tools and their targets.
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PMID:A small-molecule screen in C. elegans yields a new calcium channel antagonist. 1667 71

Home blood pressure has a higher predictive power for cardiovascular events than office blood pressure, and there is a particularly close association between morning blood pressure at home and the incidence of cardiovascular events and mortality in the early morning. In this study, we evaluated the efficacy of a long-acting N-type and L-type calcium channel blocker, cilnidipine, in reducing morning blood pressure at home and in ameliorating the white-coat effect. Fifty-eight subjects diagnosed with both essential hypertension and morning hypertension (43 currently being treated, 15 new patients) were prescribed cilnidipine at a dosage of 10-20 mg per day for 8 weeks. After the addition of or a change to cilnidipine, the morning systolic blood pressure (SBP) was controlled to less than 135 mmHg in 25 (58%) out of the 43 patients currently receiving antihypertensive medication. The office SBP in 24 out of those 25 patients was also maintained under 140 mmHg. In the 15 newly treated patients, the morning SBP of 12 patients (80%) was controlled to less than 135 mmHg after administration of cilnidipine. At baseline, 17 patients showed a clear white-coat effect, in which the difference between office blood pressure and home blood pressure was 20/10 mmHg or more. The white-coat effect was depressed significantly after cilnidipine administration. These results suggest that cilnidipine may serve as a useful antihypertensive medication in the treatment of morning hypertension, and also attenuate the white-coat effect in patients with essential hypertension.
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PMID:Beneficial effect of cilnidipine on morning hypertension and white-coat effect in patients with essential hypertension. 1836 12

Effects of a new lipophilic L-type calcium channel blocker, azelnidipine, on the expression of molecular components of the renin-angiotensin-aldosterone system (RAAS) were assessed. Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of diabetes with hypertension, and their lean littermates, Long-Evans Tokushima Otsuka (LETO) rats, were treated with azelnidipine for 2 weeks. The renal cortical mineralocorticoid receptor mRNA in OLETF was higher than in LETO, but was suppressed (P<0.05) by azelnidipine. Renal cortical angiotensin-converting enzyme mRNA of OLETF was lower than that of LETO rats, and it was further suppressed by azelnidipine (P<0.05). Azelnidipine can down-regulate the gene expression of molecular components of RAAS.
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PMID:Azelnidipine down-regulates renal angiotensin-converting enzyme and mineralocorticoid receptor mRNA in diabetic hypertensive rats. 1703 Oct 66

The calcium channel antagonists are a mature group of drugs directed at cardiovascular diseases including hypertension, angina, peripheral vascular disorders and some arrhythmic conditions. Their sites and mechanisms of actions have been well explored over the past two decades and their interactions at the alpha(1) subunit of L-type channels (Ca(V)1.1-1.4) have made them valuable molecular tools for channel classification and localization. With the realization that other members of the voltage-gated calcium channel family exist--Ca(V)2.1-2.3 and Ca(V)3.1-3.3--considerable effort has been directed to drug discovery at these channel types where therapeutic prospects exist for a variety of disorders including pain, epilepsy, affective disorders, neurodegenerative disorders, etc. In contrast to the situation with the L-type channel antagonists success in developing small molecule antagonists of therapeutic utility for these other channel types has thus far been lacking. The reasons for this are explored and potential new directions are indicated including male fertility, bone growth, immune disorders, cancer and schistosomiasis.
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PMID:Calcium channel antagonists: clinical uses--past, present and future. 1727 8


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