Abstract
Calcium is a major second messenger in neurons and modulates many neuronal functions, including protein phosphorylation, phospholipid metabolism, cytoskeletal activity, and neurotransmitter release. These important events, which regulate neuronal activity, are directly dependent on the influx of extracellular calcium through voltage-sensitive calcium channels (VSCCs) in the neuronal membrane. Modulation of VSCC function represents an important strategy for regulating neuronal excitability. Although substantial evidence supports the ability of dihydropyridines to block VSCCs and contractility in cardiovascular tissue, their ability to block the majority of neuronal VSCCs remains controversial. Benzodiazepines, and other anticonvulsants, block depolarization-dependent 45Ca uptake through VSCCs in brain synaptosome preparations. In addition, benzodiazepines reduce voltage-gated calcium conductance as determined by voltage clamp studies of identified invertebrate neurons. Inhibition of VSCC activity may be an important mechanism by which these compounds produce their anticonvulsant and sedative effects. Intrasomal injection of calcium-calmodulin-dependent protein kinase modulates calcium conductance in invertebrate neurons, suggesting that protein phosphorylation may be an endogenous regulatory mechanism of VSCC activity. Developing novel pharmacological approaches to regulating VSCCs and understanding the endogenous regulatory mechanisms may lead to new therapeutic approaches to the treatment of neurological diseases.
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Selected References
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- Bolger G. T., Gengo P., Klockowski R., Luchowski E., Siegel H., Janis R. A., Triggle A. M., Triggle D. J. Characterization of binding of the Ca++ channel antagonist, [3H]nitrendipine, to guinea-pig ileal smooth muscle. J Pharmacol Exp Ther. 1983 May;225(2):291–309. [PubMed] [Google Scholar]
- Braestrup C., Squires R. F. Pharmacological characterization of benzodiazepine receptors in the brain. Eur J Pharmacol. 1978 Apr 1;48(3):263–270. doi: 10.1016/0014-2999(78)90085-7. [DOI] [PubMed] [Google Scholar]
- DeLorenzo R. J. Calmodulin in neurotransmitter release and synaptic function. Fed Proc. 1982 May;41(7):2265–2272. [PubMed] [Google Scholar]
- Ferrendelli J. A., Daniels-McQueen S. Comparative actions of phenytoin and other anticonvulsant drugs on potassium- and veratridine-stimulated calcium uptake in synaptosomes. J Pharmacol Exp Ther. 1982 Jan;220(1):29–34. [PubMed] [Google Scholar]
- Fleckenstein A. Specific pharmacology of calcium in myocardium, cardiac pacemakers, and vascular smooth muscle. Annu Rev Pharmacol Toxicol. 1977;17:149–166. doi: 10.1146/annurev.pa.17.040177.001053. [DOI] [PubMed] [Google Scholar]
- Gould R. J., Murphy K. M., Snyder S. H. [3H]nitrendipine-labeled calcium channels discriminate inorganic calcium agonists and antagonists. Proc Natl Acad Sci U S A. 1982 Jun;79(11):3656–3660. doi: 10.1073/pnas.79.11.3656. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Johansen J., Taft W. C., Yang J., Kleinhaus A. L., DeLorenzo R. J. Inhibition of Ca2+ conductance in identified leech neurons by benzodiazepines. Proc Natl Acad Sci U S A. 1985 Jun;82(11):3935–3939. doi: 10.1073/pnas.82.11.3935. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Katz B., Miledi R. Further study of the role of calcium in synaptic transmission. J Physiol. 1970 May;207(3):789–801. doi: 10.1113/jphysiol.1970.sp009095. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leslie S. W., Friedman M. B., Coleman R. R. Effects of chlordiazepoxide on depolarization-induced calcium influx into synaptosomes. Biochem Pharmacol. 1980 Sep 15;29(18):2439–2443. doi: 10.1016/0006-2952(80)90347-0. [DOI] [PubMed] [Google Scholar]
- Nachshen D. A., Blaustein M. P. The effects of some organic "calcium antagonists" on calcium influx in presynaptic nerve terminals. Mol Pharmacol. 1979 Sep;16(2):576–586. [PubMed] [Google Scholar]
- Reuter H. Calcium channel modulation by neurotransmitters, enzymes and drugs. Nature. 1983 Feb 17;301(5901):569–574. doi: 10.1038/301569a0. [DOI] [PubMed] [Google Scholar]
- Rubin R. P. The role of calcium in the release of neurotransmitter substances and hormones. Pharmacol Rev. 1970 Sep;22(3):389–428. [PubMed] [Google Scholar]
- Sakakibara M., Alkon D. L., DeLorenzo R., Goldenring J. R., Neary J. T., Heldman E. Modulation of calcium-mediated inactivation of ionic currents by Ca2+/calmodulin-dependent protein kinase II. Biophys J. 1986 Aug;50(2):319–327. doi: 10.1016/S0006-3495(86)83465-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taft W. C., DeLorenzo R. J. Micromolar-affinity benzodiazepine receptors regulate voltage-sensitive calcium channels in nerve terminal preparations. Proc Natl Acad Sci U S A. 1984 May;81(10):3118–3122. doi: 10.1073/pnas.81.10.3118. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsien R. W. Calcium channels in excitable cell membranes. Annu Rev Physiol. 1983;45:341–358. doi: 10.1146/annurev.ph.45.030183.002013. [DOI] [PubMed] [Google Scholar]
- Turner T. J., Goldin S. M. Calcium channels in rat brain synaptosomes: identification and pharmacological characterization. High affinity blockade by organic Ca2+ channel blockers. J Neurosci. 1985 Mar;5(3):841–849. doi: 10.1523/JNEUROSCI.05-03-00841.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
