Volume-sensitive chloride channels in mouse cortical neurons: characterization and role in volume regulation.
Because persistent swelling causes cell damage and often results in cell death, volume regulation is an important physiological function in both neuronal and non-neuronal cells. Brain cell swelling has been observed not only in various pathological conditions but also during physiological synaptic transmissions. Volume-sensitive anion channels have been reported to play an important role in the regulatory volume decrease occurring after osmotic swelling in many cell types. In this study, using a two-photon laser scanning microscope and patch-clamp techniques, we found that mouse cortical neurons in primary culture exhibit regulatory volume decrease after transient swelling and activation of Cl- currents during exposure to a hypotonic solution. The regulatory volume decrease was inhibited by Cl- channel blockers or K+ channel blockers. Swelling-activated Cl- currents exhibited outward rectification, time-dependent inactivation at large positive potentials, a low-field anion permeability sequence, an intermediate unitary conductance and sensitivity to known blockers of volume-sensitive Cl- channels. Thus, it is concluded that the activity of the volume-sensitive outwardly rectifying Cl- channel plays a role in the control of cell volume in cortical neurons.
Inoue
Hana
H
Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki 444-8585, Japan.
Mori
Shin-Ichiro
S
Morishima
Shigeru
S
Okada
Yasunobu
Y
D000818:Animals; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000502:physiology*; D007038:Hypotonic Solutions / Q000494:pharmacology; D007552:Isotonic Solutions / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000187:drug effects / Q000502:physiology*
D018118:Chloride Channels; D007038:Hypotonic Solutions; D007552:Isotonic Solutions