ASIC1a
Acid Sensing Ion Channel 1A
(Alternative nomenclature: Brain sodium channel 2, BNaC2)
ASIC1a is an extracellular tetrameric proton-gated cation channel that is important for nociception. Each subunit has 2 TM. Ion permeability: Na+ > Ca2+ > K+
Localization:
Dorsal root ganglia and sciatic nerve. Widely distributed throughout the brain: olfactory bulb, neo and allocortical regions, dentate granule cells, pyramidal cells of hippocampus formation, basolateral amygdaloid nuclei, and in the Purkinje and granule cells of the cerebellum.
Information links:
http://www.expasy.org/cgi-bin/niceprot.pl?P55926
QPatch recording of ASIC1a receptor currents:
Whole-cell ASIC1a current responses to four successive exposures to extracellular Ringer’s solutions of decreasing pH from 7.3 to 4.3. Peak currents are identified between the green cursors. Expression system HEK-293
Pharmacological profiling:
Antagonists: Amiloride
Agonists: H+
(The list is not intended to be complete)
QPatch concentration-response analysis:
Effects of four increasing concentrations of amiloride on whole-cell ASIC1a currents. Cursors at 3000 and 4500 ms define the time interval in which peak current was identified.
Concentration-response relationship for the effect of amiloride on peak ASIC1a receptor currents
based on the data above. Current values were corrected for the leak.
Pathophysiology:
Focal ischemia or acidosis. Possible role in cell injury. May contribute to fear and anxiety disorders
Recent review articles:
Hesselager M, Timmermann DB, Ahring PK. pH Dependency and desensitization kinetics of heterologously expressed combinations of acid-sensing ion channel subunits. J Biol Chem,19,279,2004.
QPatch written material:
Application reports:
Targeting ligand gated ion channels
Posters:Pharmacological Characterization of Voltage- and Ligand-gated Ion Channels by
QPatch, Japanese Pharmacological Meeting 2006 (kB 424)
Assessing Functional Properties of Ligand-gated Ion Channels with Automated Whole-
Cell Patch-Clamp Technology, The BiophysicalSociety Annual Meeting 2006 (kB 920)
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