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Title: Intracellular nucleotides and polyamines inhibit the Ca2+-activated cation channel TRPM4b
Authors: Nilius, Bernd ×
Prenen, Jean
Voets, Thomas
Droogmans, Guy #
Issue Date: Apr-2004
Publisher: Springer-Verlag
Series Title: Pflügers Archiv: European journal of physiology vol:448 issue:1 pages:70-5
Abstract: TRPM4b (in contrast to the short splice variant TRPM4a) is a Ca(2+)-activated but Ca(2+)-impermeable cation channel. We have studied TRPM4 currents in inside-out patches. Supramicromolar Ca(2+) concentrations applied at the inner side, [Ca(2+)](i), activated TRPM4 with an EC(50) value of 0.37 mM, a value that is much higher than that of whole-cell currents. Current amplitudes decreased above 1 mM [Ca(2+)](i), (IC(50) 9.3 mM). Sr(2+) but not Ba(2+)could partially substitute for Ca(2+). ATP, ADP, AMP and AMP-PNP all quickly and reversibly inhibited TRPM4 with IC(50) values between 2 and 19 microM (at +100 mV). Adenosine also blocked TRPM4 at 630 microM. The block at high ATP concentrations was incomplete and was not affected by the presence of free Mg(2+). ADP induced the most sensitive block with an IC(50) of 2.2 microM. For inhibition of TRPM4 by free ATP(4-), an IC(50) value of 1.7+/-0.3 microM was calculated. GTP, UTP and CTP at concentrations up to 1 mM did not induce a similar block. Spermine blocked TRPM4 currents with an IC(50) of 61 microM. In conclusion, TRPM4 is a channel that can be effectively modulated by intracellular nucleotides and polyamines.
URI: 
ISSN: 0031-6768
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Physiology Section (-)
Laboratory of Ion Channel Research
Department of Cellular and Molecular Medicine - miscellaneous
× corresponding author
# (joint) last author

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