Calcium channel function will be examined using electrophysiological methods. The present proposal is directed toward specific aspects of activation, inactivation, conduction in open channels and regulation of channel numbers. A complete experimental picture of Ca channel gating and conduction and regulation of Ca channel numbers is the long term goal. The combined suction pipette-microelectrode method for voltage clamp and internal perfusion of isolated snail nerve cell bodies will be used in conjunction with the cell-attached patch clamp method for recording from single channels. The patch clamp method will also be applied to PC-12 cells for whole cell voltage clamping and the study of membrane patches. Macroscopic currents will be analyzed using exponential fitting. Microscopic current fluctuations will be analyzed using noise spectra and impedance plots. The open time and frequency of opening of single channels will be measured. Correlation among the three different approaches, macroscopic currents, microscopic fluctuations and single channel openings will be made and specific models of activation, inactivation and conduction will be examined. Regulation of functional Ca channel numbers by intracellular Ca, neural transmitters, organic Ca channel blockers and divalent cations will also be investigated. The studies are being extended to PC-12 cells for several reasons: for comparative purposes, because membrane patches in a variety of configurations (inside-out, outside-out, cell-attached) are readily studied and because binding studies and other biochemical studies are being done on this cell line. Calcium channels are the link between excitation and a number of important cellular functions such as contraction and secretion. They are important in the function of the nervous and musculoskeletal systems and the endocrine systems and, therefore, may be involved in the numerous diseases that affect these systems.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS023877-05
Application #
3407872
Study Section
Physiology Study Section (PHY)
Project Start
1985-12-01
Project End
1990-11-30
Budget Start
1989-12-01
Budget End
1990-11-30
Support Year
5
Fiscal Year
1990
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Kuryshev, Y A; Wible, B A; Gudz, T I et al. (2001) KChAP/Kvbeta1.2 interactions and their effects on cardiac Kv channel expression. Am J Physiol Cell Physiol 281:C290-9
Bianchi, L; Priori, S G; Napolitano, C et al. (2000) Mechanisms of I(Ks) suppression in LQT1 mutants. Am J Physiol Heart Circ Physiol 279:H3003-11
Kuryshev, Y A; Gudz, T I; Brown, A M et al. (2000) KChAP as a chaperone for specific K(+) channels. Am J Physiol Cell Physiol 278:C931-41
Bianchi, L; Shen, Z; Dennis, A T et al. (1999) Cellular dysfunction of LQT5-minK mutants: abnormalities of IKs, IKr and trafficking in long QT syndrome. Hum Mol Genet 8:1499-507
Wible, B A; Yang, Q; Kuryshev, Y A et al. (1998) Cloning and expression of a novel K+ channel regulatory protein, KChAP. J Biol Chem 273:11745-51
Kramer, J W; Post, M A; Brown, A M et al. (1998) Modulation of potassium channel gating by coexpression of Kv2.1 with regulatory Kv5.1 or Kv6.1 alpha-subunits. Am J Physiol 274:C1501-10
Dumaine, R; Roy, M L; Brown, A M (1998) Blockade of HERG and Kv1.5 by ketoconazole. J Pharmacol Exp Ther 286:727-35
Accili, E A; Kuryshev, Y A; Wible, B A et al. (1998) Separable effects of human Kvbeta1.2 N- and C-termini on inactivation and expression of human Kv1.4. J Physiol 512 ( Pt 2):325-36
Accili, E A; Kiehn, J; Wible, B A et al. (1997) Interactions among inactivating and noninactivating Kvbeta subunits, and Kvalpha1.2, produce potassium currents with intermediate inactivation. J Biol Chem 272:28232-6
Accili, E A; Kiehn, J; Yang, Q et al. (1997) Separable Kvbeta subunit domains alter expression and gating of potassium channels. J Biol Chem 272:25824-31

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