title: Blockade of T-type voltage-dependent Ca2+ channels by benidipine, a dihydropyridine calcium channel blocker, inhibits aldosterone production in human adrenocortical cell line NCI-H295R.
abstract: Benidipine, a long-lasting dihydropyridine calcium channel blocker, is used for treatment of hypertension and angina. Benidipine exerts pleiotropic pharmacological features, such as renoprotective and cardioprotective effects. In pathophysiological conditions, the antidiuretic hormone aldosterone causes development of renal and cardiovascular diseases. In adrenal glomerulosa cells, aldosterone is produced in response to extracellular potassium, which is mainly mediated by T-type voltage-dependent Ca2+ channels. More recently, it has been demonstrated that benidipine inhibits T-type Ca2+ channels in addition to L-type Ca2+ channels. Therefore, effect of calcium channel blockers, including benidipine, on aldosterone production and T-type Ca2+ channels using human adrenocortical cell line NCI-H295R was investigated. Benidipine efficiently inhibited KCl-induced aldosterone production at low concentration (3 and 10 nM), with inhibitory activity more potent than other calcium channel blockers. Patch clamp analysis indicated that benidipine concentration-dependently inhibited T-type Ca2+ currents at 10, 100 and 1000 nM. As for examined calcium channel blockers, inhibitory activity for T-type Ca2+ currents was well correlated with aldosterone production. L-type specific calcium channel blockers calciseptine and nifedipine showed no effect in both assays. These results indicate that inhibition of T-type Ca2+ channels is responsible for inhibition of aldosterone production in NCI-H295R cells. Benidipine efficiently inhibited KCl-induced upregulation of 11-beta-hydroxylase mRNA and aldosterone synthase mRNA as well as KCl-induced Ca2+ influx, indicating it as the most likely inhibition mechanism. Benidipine partially inhibited angiotensin II-induced aldosterone production, plus showed additive effects when used in combination with the angiotensin II type I receptor blocker valsartan. Benidipine also partially inhibited angiotensin II-induced upregulation of the above mRNAs and Ca2+ influx inhibitory activities of benidipine for aldosterone production. T-type Ca2+ channels may contribute to additional benefits of this drug for treating renal and cardiovascular diseases, beyond its primary anti-hypertensive effects from blocking L-type Ca2+ channels.
authors.affiliation: Pharmaceutical Research Center, Kyowa Hakko Kogyo Co., Ltd., Shizuoka 411-8731, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Akizuki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Inayoshi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Kitayama
authors.forename: Kozo
authors.initials: K
authors.lastname: Yao
authors.forename: Shiro
authors.initials: S
authors.lastname: Shirakura
authors.forename: Katsutoshi
authors.initials: K
authors.lastname: Sasaki
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kusaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Matsubara
mesh_terms: D000302:Adrenal Cortex / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D000450:Aldosterone / Q000378:metabolism*; D000804:Angiotensin II / Q000378:metabolism; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism; D020747:Calcium Channels, T-Type / Q000187:drug effects* / Q000378:metabolism; D002460:Cell Line; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics / Q000378:metabolism; D004095:Dihydropyridines / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D008564:Membrane Potentials; D018408:Patch-Clamp Techniques; D011189:Potassium Chloride / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D013252:Steroid 11-beta-Hydroxylase / Q000235:genetics / Q000378:metabolism; D013777:Tetrazoles / Q000494:pharmacology; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology; D000068756:Valsartan
chemical_list: D047228:Angiotensin II Type 1 Receptor Blockers; D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D004095:Dihydropyridines; D012333:RNA, Messenger; D013777:Tetrazoles; D000804:Angiotensin II; D000450:Aldosterone; C061004:benidipine; D011189:Potassium Chloride; D000068756:Valsartan; D019405:Cytochrome P-450 CYP11B2; D013252:Steroid 11-beta-Hydroxylase; D014633:Valine; D002118:Calcium