Ionic currents and receptors in the physiology of excitable and non-excitable cells

• Grant number: 06/50954-7
• Support Opportunities: Research Projects - Thematic Grants
• Start date: August 01, 2006
• End date: July 31, 2010
• Field of knowledge: Biological Sciences - Biophysics - Cellular Biophysics
• Principal Investigator: Wamberto Antonio Varanda
• Grantee: Wamberto Antonio Varanda
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated scholarship(s): 09/06036-1 - Store operated calcium entry in mice Leydig cells, BP.IC; 08/10000-0 - P2X subunits expression in mice Leydig cells at different ages and interactions amongst P2X2, P2X4, P2X6 subunits forming functional purinergic receptors, BP.DR

Abstract

This project is concerned with ion transport in Leydig cells and in cells of neural tissue (supra optic nucleus) aiming at an understanding of the role played by specific receptors and ionic currents in the physiological processes carried out by these cells. Although both cells are involved in secretor processes, testosterone in one case and ADH in the other, we intend to use the patch clamp technique in order to get information about the major ions participating in their physiology, coupled to current molecular biology techniques to identify specific receptors and calcium ion fluorescence to evaluate changes in the intracellular concentration of this ion. The expected results should contribute to the understanding of the secretor processes, important for the determination of the male sexual characteristics in one case and for the maintenance of the osmolality of the extracellular fluid in the other: both crucial phenomena for the maintenance of life. Under a theoretical perspective we intend to use mathematical tools (Hiden Markov Chains) to analyze single channel ionic currents through calcium activated potassium channels, known to be expressed in Leydig cells. The expected results should contribute to the understanding of the physical mechanisms controlling the transitions between the closed and open conformation of the protein forming the channel. (AU)

Scientific publications

(9)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ANTONIO, LIGIA SUBITONI; COSTA, ROBERTA RIBEIRO; GOMES, MARCELO DAMARIO; VARANDA, WAMBERTO ANTONIO. Mouse Leydig cells express multiple P2X receptor subunits. PURINERGIC SIGNALLING, v. 5, n. 3, p. 277-287, SEP 2009. (06/50954-7)

COSTA, ROBERTA RIBEIRO; DOS REIS, ROSANA INACIO; AGUIAR, JOSE FERNANDO; VARANDA, WAMBERTO ANTONIO. Luteinizing hormone (LH) acts through PKA and PKC to modulate T-type calcium currents and intracellular calcium transients in mice Leydig cells. Cell Calcium, v. 49, n. 3, p. 191-199, MAR 2011. (06/50954-7)

COSTA, ROBERTA RIBEIRO; VARANDA, WAMBERTO ANTÔNIO. Intracellular calcium changes in mice Leydig cells are dependent on calcium entry through T-type calcium channels. JOURNAL OF PHYSIOLOGY-LONDON, v. 585, n. 2, p. 339-349, Dec. 2007. (06/50954-7)

COSTA, ROBERTA RIBEIRO; VARANDA, WAMBERTO ANTONIO; FRANCI, CELSO RODRIGUES. A calcium-induced calcium release mechanism supports luteinizing hormone-induced testosterone secretion in mouse Leydig cells. AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY, v. 299, n. 2, p. C316-C323, AUG 2010. (06/50954-7)

ANTONIO, LIGIA S.; STEWART, ANDREW P.; VARANDA, WAMBERTO A.; EDWARDSON, J. MICHAEL. Identification of P2X2/P2X4/P2X6 heterotrimeric receptors using atomic force microscopy (AFM) imaging. FEBS Letters, v. 588, n. 12, p. 2125-2128, JUN 5 2014. (08/10000-0, 06/50954-7)

DA SILVA, M. P.; VENTURA, R. R.; VARANDA, W. A.. HYPERTONICITY INCREASES NO PRODUCTION TO MODULATE THE FIRING RATE OF MAGNOCELLULAR NEURONS OF THE SUPRAOPTIC NUCLEUS OF RATS. Neuroscience, v. 250, p. 70-79, OCT 10 2013. (10/16600-9, 06/50954-7)

ANTONIO, L. S.; STEWART, A. P.; XU, X. J.; VARANDA, W. A.; MURRELL-LAGNADO, R. D.; EDWARDSON, J. M.. P2X4 receptors interact with both P2X2 and P2X7 receptors in the form of homotrimers. British Journal of Pharmacology, v. 163, n. 5, p. 1069-1077, JUL 2011. (06/50954-7)

ROSALES, RAFAEL A.; VARANDA, WAMBERTO A.. Allosteric Control of Gating Mechanisms Revisited: The Large Conductance Ca2+-Activated K+ Channel. BIOPHYSICAL JOURNAL, v. 96, n. 10, p. 3987-3996, MAY 20 2009. (05/02063-3, 06/50954-7)

POLETTO CHAVES, LUIZ ARTUR; VARANDA, WAMBERTO ANTONIO. Volume-activated chloride channels in mice Leydig cells. PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, v. 457, n. 2, p. 493-504, NOV 2008. (06/50954-7)