Regulation of Cardiac Calcium Current during Suppression of Second Messenger Intracellular Enzymatic Pathways
It is well established that membrane ionic channels in heart cells are up-regulated by enhanced activation of intracellular enzymatic cascades (1–3). However, less is known about channel regulation and modulation under conditions of depressed enzymatic activity such as might occur in the failing heart. In this study, we have developed protocols to suppress pertinent enzymatic activity in guinea pig ventricular myocytes, and examined the consequences on whole-cell calcium current (ICa) and its modulation.
KeywordsInositol Trisphosphate Phosphorylation Pathway Adenyl Cyclase System Channel Phosphorylation Modify Tyrode Solution
Unable to display preview. Download preview PDF.
- 4.Trautwein, W., Kameyama, M., Hescheler, J. and Hofmann, F. Cardiac calcium channels and their transmitter modulation. Prog. Zool. 33: 163–182, 1986.Google Scholar
- 6.Birnbaumer, L., Codina, J. Mattera, R., Yatani, A., Scherer, N., Toro, M. and Brown, A.M. Signal transduction by G proteins. Kidney Int. 32: 514537, 1987.Google Scholar
- 7.Hescheler, J., Kameyama, M. and Trautwein, W. On the mechanism of muscarinic inhibition of the cardiac Ca current. Pflügers Arch. 407: 18 2189, 1986.Google Scholar
- 8.Isenberg, G., Cerbai, E. and Klöckner, U. Ionic channels and adenosine in isolated heart cells. In: Topics and Perspectives in Adenosine Research, (edited by E. Gerlach and B.F. Becker ). Springer-Verlag, Berlin, Heidelberg, 1987, pp. 323–335.Google Scholar
- 20.Yount, R.G. ATP analogs. Adv. Enzymol. 34: 1–36, 1975.Google Scholar
- 32.Imoto, Y., Yatani, A., Reeves, J.P., Codina, J., Birnbaumer, L. and Brown, A.M. α-Subunit of Gs directly activates cardiac calcium channels in lipid bilayers. A.. J. Physiol. 255: H722–H728, 1988.Google Scholar
- 33.Yatani, A., Imoto, Y., Codina, J., Hamilton, S.L., Brown, A.M. and Birnbaumer, L. The stimulatory G protein of adenylyl cyclase, Gs, also stimulates dihydropyridine-sensitive Ca2+ channels. Evidence for direct regulation independent of phosphorylation by cAMP-dependent protein kinase or stimulation by a dihydropyridine agonist. J. Biol. Chem. 263: 9887–9895, 1988.Google Scholar