Regulation of the L-type calcium channel

Hofmann, Franz; Nastainczyk, Wolfgang; Röhrkasten, Axel; Schneider, Toni; Sieber, Manfred

doi:10.1016/0165-6147(87)90103-9

Cited by 128 publications

(48 citation statements)

References 30 publications

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“…The dihydropyridine derivative, nifedipine, had relatively little influence while La3" ions were inactive. In contrast, Ni2+ and Mn2' ions, which are reported to inhibit Ca2+ conductance through T-type VSCC and to suppress the fast component of the contractile response in smooth muscle associated with the opening of rapidly inactivating VSCC (Brading et al, 1983;Hofmann et al, 1987), strongly inhibited the rhythmic activity in the vas deferens. These results are in good agreement with the previous observations of Langton & Huddard (1987).…”

Section: Discussionmentioning

confidence: 99%

Calcium modulatory properties of 2,6‐dibutylbenzylamine (B25) in rat isolated vas deferens, cardiac and smooth muscle preparations

Pirisino¹,

Banchelli²,

Ignesti³

et al. 1993

British J Pharmacology

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1 In rat isolated vas deferens the new compound 2,6-dibutylbenzylamine (B25) evoked a series of repeating rhythmic contractions. Concentration-response curves constructed for this effect were bellshaped, indicating a biphasic effect for this compound. By contrast, B25 depressed heart contractility without any visible positive inotropic or chronotropic activity. 2 Experiments with tetrodotoxin, reserpine, capsaicin, a-adrenoceptor blocking compounds and other agents permit us to exclude a release of neuromediators or a direct stimulation of post-synaptic receptors to account for the rhythmic effect of B25 in the rat vas deferens.3 In the same tissue, the increase in 45Ca2" uptake, the voltage-dependency as well as the dependence of the B25-induced rhythmic activity upon the external calcium concentration indicate a direct activation of voltage-sensitive calcium channels (VSCC). 4 Verapamil paradoxically stimulated the rhythmic effect of B25 in the rat vas deferens. La3+ was inactive while nifedipine was a weak inhibitor. By contrast Ni2" and Mn2" ions were good inhibitors (IC50 < 10-4M), suggesting that a possible opening of T-type VSCC underlies the rhythmic effect of B25. 5 In radioligand binding studies competition experiments with [3H]-nitrendipine indicated that only at high concentrations was B25 able to interact with dihydropyridine-sensitive binding sites of heart and vas deferens smooth muscle. 6 B25 (3-30 pLM) counteracted the inhibitory effects of c-conotoxin GVIA in field-stimulated rat vas deferens.

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Section: Discussionmentioning

confidence: 99%

Calcium modulatory properties of 2,6‐dibutylbenzylamine (B25) in rat isolated vas deferens, cardiac and smooth muscle preparations

Pirisino¹,

Banchelli²,

Ignesti³

et al. 1993

British J Pharmacology

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“…Verapamil as well as other Ca antagonists, dihydropyridines and diltiazem, are well known to inhibit Ca-entry into the cell through the L-type, voltage-dependent Ca channels (24). Using this drug, we then deter mined to what extent the Ca influx contributes to the carbachol and ATP-induced contrac tions.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Contractile Mechanisms by Carbachol and ATP in Detrusor Strips of Rabbit Urinary Bladder.

1992

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Contractile mechanisms by carbachol and ATP were compared in the detrusor strips of rabbit bladder. To exclude modulation of the agonists-induced re sponses by intramurally synthesized prostaglandins, all the experiments were done in the presence of the potent cyclooxygenase inhibitor flurbiprofen (1 UM). The concentration-response curves for carbachol and ATP were shifted to the right by 6 10-fold by verapamil (10,uM), which abolished the K-induced contraction of the atropinized detrusor completely. A similar curve for carbachol was obtained in the absence of extracellular Ca [(Ca),,], but the contraction by ATP below 1 mM was more reduced by (Ca),,-depletion than by verapamil. Under Ca-free conditions, re peated applications of ATP resulted in no response, but those of carbachol induced reproducible contractions. These results suggest that carbachol and ATP induces Ca influx through L-type Ca channels and releases Ca from the Ca stores. However, while carbachol might increase the sensitivity of contractile machinery to Ca on the one hand, ATP would open additional, verapamil-insensitive Ca channels.

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“…Since the classification of (-adrenergic The genes encoding the a,-, a2-, 1PI-, and 132-AR have been isolated (1)(2)(3)(4). They belong to a family of homologous genes that encode integral membrane receptors (5, 6), which presumably have seven membranespanning domains and which are coupled to regulatory G proteins.…”

Section: S -mentioning

confidence: 99%

“…: United Nations Development Pro- T HE DIHYDROPYRIDINE (DHP)-SENsitive Ca2+ channel seems to play an important role in excitation-contraction coupling, and when purified from rabbit skeletal muscle, it contains three main subunits with molecular masses of 165,000 (a,), 55,000 (13), and 32,000 daltons (-y) (1)(2)(3)(4)(5)(6)(7)(8)(9). Both the a1 and the 13 subunits are substrates for protein kinases in vitro, and phosphorylation of these subunits may serve to regulate the in vivo function of the Ca2+ channel (1)(2)(3)(4)(5). A disulfide-linked dimer of 130,000-(a2) and 28,000-dalton (8) polypeptides has been observed in preparations of the channel either in variable (6) or constant (7) amounts with respect to the other subunits.…”

mentioning

confidence: 99%

Primary Structure of the β Subunit of the DHP-Sensitive Calcium Channel from Skeletal Muscle

Ruth¹,

Röhrkasten²,

Biel³

et al. 1989

Science

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347

165

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Regulation of the L-type calcium channel

Cited by 128 publications

References 30 publications

Calcium modulatory properties of 2,6‐dibutylbenzylamine (B25) in rat isolated vas deferens, cardiac and smooth muscle preparations

Calcium modulatory properties of 2,6‐dibutylbenzylamine (B25) in rat isolated vas deferens, cardiac and smooth muscle preparations

Comparison of Contractile Mechanisms by Carbachol and ATP in Detrusor Strips of Rabbit Urinary Bladder.

Primary Structure of the β Subunit of the DHP-Sensitive Calcium Channel from Skeletal Muscle

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