Abstract
Nickel has been proposed to be a selective blocker of low-voltage-activated, T-type calcium channels. However, studies on cloned high-voltage-activated Ca(2+) channels indicated that some subtypes, such as alpha1E, are also blocked by low micromolar concentrations of NiCl(2). There are considerable differences in the sensitivity to Ni(2+) among native T-type currents, leading to the hypothesis that there may be more than one T-type channel. We confirmed part of this hypothesis by cloning three novel Ca(2+) channels, alpha1G, H, and I, whose currents are nearly identical to the biophysical properties of native T-type channels. In this study we examined the nickel block of these cloned T-type channels expressed in both Xenopus oocytes and HEK-293 cells (10 mM Ba(2+)). Only alpha1H currents were sensitive to low micromolar concentrations (IC(50) = 13 microM). Much higher concentrations were required to half-block alpha1I (216 microM) and alpha1G currents (250 microM). Nickel block varied with the test potential, with less block at potentials above -30 mV. Outward currents through the T channels were blocked even less. We show that depolarizations can unblock the channel and that this can occur in the absence of permeating ions. We conclude that Ni(2+) is only a selective blocker of alpha1H currents and that the concentrations required to block alpha1G and alpha1I will also affect high-voltage-activated calcium currents.
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- Akaike N., Kanaide H., Kuga T., Nakamura M., Sadoshima J., Tomoike H. Low-voltage-activated calcium current in rat aorta smooth muscle cells in primary culture. J Physiol. 1989 Sep;416:141–160. doi: 10.1113/jphysiol.1989.sp017754. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Berjukow S., Döring F., Froschmayr M., Grabner M., Glossmann H., Hering S. Endogenous calcium channels in human embryonic kidney (HEK293) cells. Br J Pharmacol. 1996 Jun;118(3):748–754. doi: 10.1111/j.1476-5381.1996.tb15463.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bezprozvanny I., Tsien R. W. Voltage-dependent blockade of diverse types of voltage-gated Ca2+ channels expressed in Xenopus oocytes by the Ca2+ channel antagonist mibefradil (Ro 40-5967). Mol Pharmacol. 1995 Sep;48(3):540–549. [PubMed] [Google Scholar]
- Carbone E., Lux H. D. A low voltage-activated, fully inactivating Ca channel in vertebrate sensory neurones. Nature. 1984 Aug 9;310(5977):501–502. doi: 10.1038/310501a0. [DOI] [PubMed] [Google Scholar]
- Chuang R. S., Jaffe H., Cribbs L., Perez-Reyes E., Swartz K. J. Inhibition of T-type voltage-gated calcium channels by a new scorpion toxin. Nat Neurosci. 1998 Dec;1(8):668–674. doi: 10.1038/3669. [DOI] [PubMed] [Google Scholar]
- Cribbs L. L., Lee J. H., Yang J., Satin J., Zhang Y., Daud A., Barclay J., Williamson M. P., Fox M., Rees M. Cloning and characterization of alpha1H from human heart, a member of the T-type Ca2+ channel gene family. Circ Res. 1998 Jul 13;83(1):103–109. doi: 10.1161/01.res.83.1.103. [DOI] [PubMed] [Google Scholar]
- Dascal N., Snutch T. P., Lübbert H., Davidson N., Lester H. A. Expression and modulation of voltage-gated calcium channels after RNA injection in Xenopus oocytes. Science. 1986 Mar 7;231(4742):1147–1150. doi: 10.1126/science.2418503. [DOI] [PubMed] [Google Scholar]
- Fox A. P., Nowycky M. C., Tsien R. W. Kinetic and pharmacological properties distinguishing three types of calcium currents in chick sensory neurones. J Physiol. 1987 Dec;394:149–172. doi: 10.1113/jphysiol.1987.sp016864. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fox A. P., Nowycky M. C., Tsien R. W. Single-channel recordings of three types of calcium channels in chick sensory neurones. J Physiol. 1987 Dec;394:173–200. doi: 10.1113/jphysiol.1987.sp016865. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hagiwara N., Irisawa H., Kameyama M. Contribution of two types of calcium currents to the pacemaker potentials of rabbit sino-atrial node cells. J Physiol. 1988 Jan;395:233–253. doi: 10.1113/jphysiol.1988.sp016916. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirano Y., Fozzard H. A., January C. T. Characteristics of L- and T-type Ca2+ currents in canine cardiac Purkinje cells. Am J Physiol. 1989 May;256(5 Pt 2):H1478–H1492. doi: 10.1152/ajpheart.1989.256.5.H1478. [DOI] [PubMed] [Google Scholar]
- Huguenard J. R. Low-threshold calcium currents in central nervous system neurons. Annu Rev Physiol. 1996;58:329–348. doi: 10.1146/annurev.ph.58.030196.001553. [DOI] [PubMed] [Google Scholar]
- Kaneda M., Akaike N. The low-threshold Ca current in isolated amygdaloid neurons in the rat. Brain Res. 1989 Sep 11;497(1):187–190. doi: 10.1016/0006-8993(89)90987-6. [DOI] [PubMed] [Google Scholar]
- Klugbauer N., Lacinová L., Marais E., Hobom M., Hofmann F. Molecular diversity of the calcium channel alpha2delta subunit. J Neurosci. 1999 Jan 15;19(2):684–691. doi: 10.1523/JNEUROSCI.19-02-00684.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lacerda A. E., Perez-Reyes E., Wei X., Castellano A., Brown A. M. T-type and N-type calcium channels of Xenopus oocytes: evidence for specific interactions with beta subunits. Biophys J. 1994 Jun;66(6):1833–1843. doi: 10.1016/S0006-3495(94)80977-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee J. H., Cribbs L. L., Perez-Reyes E. Cloning of a novel four repeat protein related to voltage-gated sodium and calcium channels. FEBS Lett. 1999 Feb 26;445(2-3):231–236. doi: 10.1016/s0014-5793(99)00082-4. [DOI] [PubMed] [Google Scholar]
- Lee J. H., Daud A. N., Cribbs L. L., Lacerda A. E., Pereverzev A., Klöckner U., Schneider T., Perez-Reyes E. Cloning and expression of a novel member of the low voltage-activated T-type calcium channel family. J Neurosci. 1999 Mar 15;19(6):1912–1921. doi: 10.1523/JNEUROSCI.19-06-01912.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Liman E. R., Tytgat J., Hess P. Subunit stoichiometry of a mammalian K+ channel determined by construction of multimeric cDNAs. Neuron. 1992 Nov;9(5):861–871. doi: 10.1016/0896-6273(92)90239-a. [DOI] [PubMed] [Google Scholar]
- MacKinnon R., Miller C. Mechanism of charybdotoxin block of the high-conductance, Ca2+-activated K+ channel. J Gen Physiol. 1988 Mar;91(3):335–349. doi: 10.1085/jgp.91.3.335. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Matteson D. R., Armstrong C. M. Properties of two types of calcium channels in clonal pituitary cells. J Gen Physiol. 1986 Jan;87(1):161–182. doi: 10.1085/jgp.87.1.161. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McDonough S. I., Bean B. P. Mibefradil inhibition of T-type calcium channels in cerebellar purkinje neurons. Mol Pharmacol. 1998 Dec;54(6):1080–1087. doi: 10.1124/mol.54.6.1080. [DOI] [PubMed] [Google Scholar]
- McDonough S. I., Mintz I. M., Bean B. P. Alteration of P-type calcium channel gating by the spider toxin omega-Aga-IVA. Biophys J. 1997 May;72(5):2117–2128. doi: 10.1016/S0006-3495(97)78854-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Miljanich G. P., Ramachandran J. Antagonists of neuronal calcium channels: structure, function, and therapeutic implications. Annu Rev Pharmacol Toxicol. 1995;35:707–734. doi: 10.1146/annurev.pa.35.040195.003423. [DOI] [PubMed] [Google Scholar]
- Mishra S. K., Hermsmeyer K. Selective inhibition of T-type Ca2+ channels by Ro 40-5967. Circ Res. 1994 Jul;75(1):144–148. doi: 10.1161/01.res.75.1.144. [DOI] [PubMed] [Google Scholar]
- Mlinar B., Enyeart J. J. Block of current through T-type calcium channels by trivalent metal cations and nickel in neural rat and human cells. J Physiol. 1993 Sep;469:639–652. doi: 10.1113/jphysiol.1993.sp019835. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Perez-Reyes E., Cribbs L. L., Daud A., Lacerda A. E., Barclay J., Williamson M. P., Fox M., Rees M., Lee J. H. Molecular characterization of a neuronal low-voltage-activated T-type calcium channel. Nature. 1998 Feb 26;391(6670):896–900. doi: 10.1038/36110. [DOI] [PubMed] [Google Scholar]
- Piedras-Rentería E. S., Chen C. C., Best P. M. Antisense oligonucleotides against rat brain alpha1E DNA and its atrial homologue decrease T-type calcium current in atrial myocytes. Proc Natl Acad Sci U S A. 1997 Dec 23;94(26):14936–14941. doi: 10.1073/pnas.94.26.14936. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pietrobon D., Hess P. Novel mechanism of voltage-dependent gating in L-type calcium channels. Nature. 1990 Aug 16;346(6285):651–655. doi: 10.1038/346651a0. [DOI] [PubMed] [Google Scholar]
- Randall A. D., Tsien R. W. Contrasting biophysical and pharmacological properties of T-type and R-type calcium channels. Neuropharmacology. 1997 Jul;36(7):879–893. doi: 10.1016/s0028-3908(97)00086-5. [DOI] [PubMed] [Google Scholar]
- Satoh H. Role of T-type Ca2+ channel inhibitors in the pacemaker depolarization in rabbit sino-atrial nodal cells. Gen Pharmacol. 1995 May;26(3):581–587. doi: 10.1016/0306-3623(94)00214-8. [DOI] [PubMed] [Google Scholar]
- Schreibmayer W., Lester H. A., Dascal N. Voltage clamping of Xenopus laevis oocytes utilizing agarose-cushion electrodes. Pflugers Arch. 1994 Mar;426(5):453–458. doi: 10.1007/BF00388310. [DOI] [PubMed] [Google Scholar]
- Soong T. W., Stea A., Hodson C. D., Dubel S. J., Vincent S. R., Snutch T. P. Structure and functional expression of a member of the low voltage-activated calcium channel family. Science. 1993 May 21;260(5111):1133–1136. doi: 10.1126/science.8388125. [DOI] [PubMed] [Google Scholar]
- Suzuki S., Rogawski M. A. T-type calcium channels mediate the transition between tonic and phasic firing in thalamic neurons. Proc Natl Acad Sci U S A. 1989 Sep;86(18):7228–7232. doi: 10.1073/pnas.86.18.7228. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Takahashi K., Akaike N. Calcium antagonist effects on low-threshold (T-type) calcium current in rat isolated hippocampal CA1 pyramidal neurons. J Pharmacol Exp Ther. 1991 Jan;256(1):169–175. [PubMed] [Google Scholar]
- Talley E. M., Cribbs L. L., Lee J. H., Daud A., Perez-Reyes E., Bayliss D. A. Differential distribution of three members of a gene family encoding low voltage-activated (T-type) calcium channels. J Neurosci. 1999 Mar 15;19(6):1895–1911. doi: 10.1523/JNEUROSCI.19-06-01895.1999. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thévenod F., Jones S. W. Cadmium block of calcium current in frog sympathetic neurons. Biophys J. 1992 Jul;63(1):162–168. doi: 10.1016/S0006-3495(92)81575-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Todorovic S. M., Lingle C. J. Pharmacological properties of T-type Ca2+ current in adult rat sensory neurons: effects of anticonvulsant and anesthetic agents. J Neurophysiol. 1998 Jan;79(1):240–252. doi: 10.1152/jn.1998.79.1.240. [DOI] [PubMed] [Google Scholar]
- Tseng G. N., Boyden P. A. Multiple types of Ca2+ currents in single canine Purkinje cells. Circ Res. 1989 Dec;65(6):1735–1750. doi: 10.1161/01.res.65.6.1735. [DOI] [PubMed] [Google Scholar]
- Wakamori M., Niidome T., Furutama D., Furuichi T., Mikoshiba K., Fujita Y., Tanaka I., Katayama K., Yatani A., Schwartz A. Distinctive functional properties of the neuronal BII (class E) calcium channel. Receptors Channels. 1994;2(4):303–314. [PubMed] [Google Scholar]
- Williams M. E., Marubio L. M., Deal C. R., Hans M., Brust P. F., Philipson L. H., Miller R. J., Johnson E. C., Harpold M. M., Ellis S. B. Structure and functional characterization of neuronal alpha 1E calcium channel subtypes. J Biol Chem. 1994 Sep 2;269(35):22347–22357. [PubMed] [Google Scholar]
- Williams M. E., Washburn M. S., Hans M., Urrutia A., Brust P. F., Prodanovich P., Harpold M. M., Stauderman K. A. Structure and functional characterization of a novel human low-voltage activated calcium channel. J Neurochem. 1999 Feb;72(2):791–799. doi: 10.1046/j.1471-4159.1999.0720791.x. [DOI] [PubMed] [Google Scholar]
- Ye J. H., Akaike N. Calcium currents in pyramidal neurons acutely dissociated from the rat frontal cortex: a study by the nystatin perforated patch technique. Brain Res. 1993 Mar 19;606(1):111–117. doi: 10.1016/0006-8993(93)91577-f. [DOI] [PubMed] [Google Scholar]
- Zamponi G. W., Bourinet E., Snutch T. P. Nickel block of a family of neuronal calcium channels: subtype- and subunit-dependent action at multiple sites. J Membr Biol. 1996 May;151(1):77–90. doi: 10.1007/s002329900059. [DOI] [PubMed] [Google Scholar]
- Zhang J. F., Randall A. D., Ellinor P. T., Horne W. A., Sather W. A., Tanabe T., Schwarz T. L., Tsien R. W. Distinctive pharmacology and kinetics of cloned neuronal Ca2+ channels and their possible counterparts in mammalian CNS neurons. Neuropharmacology. 1993 Nov;32(11):1075–1088. doi: 10.1016/0028-3908(93)90003-l. [DOI] [PubMed] [Google Scholar]
- Zhou Z., Lipsius S. L. T-type calcium current in latent pacemaker cells isolated from cat right atrium. J Mol Cell Cardiol. 1994 Sep;26(9):1211–1219. doi: 10.1006/jmcc.1994.1139. [DOI] [PubMed] [Google Scholar]