The FLIPR (Fluorescent Imaging Plate Reader) system has been extensively used in the early stages of drug discovery for the identification of small molecules as a starting point for drug development, and for the pharmacological characterization of compounds. The main application of the system has been the measurement of intracellular Ca(2+) signals using fluorescent calcium indicators.This chapter describes the application of a protocol for the study and characterization of state-dependent blockers of Voltage-Gated Calcium Channels (VGCC) on the FLIPR(TETRA).The cell line suitable for the application of the protocol, and described hereafter, co-expresses the human CaV1.2 channel and the human inward rectifier K(+) channel Kir2.3. The presence of Kir2.3 allows the modulation of the plasma membrane potential and consequently of the state of the CaV1.2 channel by changing the extracellular K(+) concentration. In this way, CaV1.2 activity can be measured at different membrane voltages, corresponding to either the resting or partial inactivated state, by loading the cells with a calcium probe in extracellular low or high potassium buffer.
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http://dx.doi.org/10.1007/978-1-4939-3673-1_13 | DOI Listing |
Clin Transl Sci
December 2024
Cytokinetics, South San Francisco, California, USA.
The human voltage-gated sodium channel Na1.5 (hNa1.5/SCN5A) plays a critical role in the initiation and propagation of action potentials in cardiac myocytes, and its modulation by various drugs has significant implications for cardiac safety.
View Article and Find Full Text PDFJ Clin Invest
December 2024
Department of Pharmacology and Therapeutics, College of Pharmacy, University of Florida, Gainesville, United States of America.
Eur J Pharmacol
January 2025
Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Av. 25 de Julio 965 Col, Villas San Sebastián, Colima, COL, 28045, Mexico. Electronic address:
In native tissue, Kv4.2 channels associate with the ancillary subunits Kv channels interacting proteins (KChIPs) and dipeptidyl peptidase-related proteins (DPPs) to evoke rapidly activating/inactivating currents in the heart (I) and brain (I). Despite extensive knowledge of Kv4.
View Article and Find Full Text PDFElife
November 2024
Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, United States.
Many voltage-gated potassium (Kv) channels display a time-dependent phenomenon called C-type inactivation, whereby prolonged activation by voltage leads to the inhibition of ionic conduction, a process that involves a conformational change at the selectivity filter toward a non-conductive state. Recently, a high-resolution structure of a strongly inactivated triple-mutant channel kv1.2-kv2.
View Article and Find Full Text PDFMol Pharmacol
November 2024
Department of Neurobiology (P.V., A.F., S.J., H.-X.B.Z., T.O., B.P.B.) and Laboratory of Systems Pharmacology and Harvard Program in Therapeutics (X.M.), Harvard Medical School, Boston, Massachusetts
Nav1.8 sodium channels (Nav1.8) are an attractive therapeutic target for pain because they are prominent in primary pain-sensing neurons with little expression in most other kinds of neurons.
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