Block of kainate receptor channels by Ca2+ in isolated spinal trigeminal neurons of rat.
Compared with N-methyl-D-aspartate-activated channels, the interaction of Ca2+ with kainate-activated or with quisqualate-activated channels is not well understood. We have studied the effect of Ca2+ on kainate-activated currents in isolated trigeminal neurons and found that Ca2+ inhibits kainate responses. This inhibition occurs not because Ca2+ changes the affinity of kainate to its receptor, but because Ca2+ blocks monovalent cation permeation through kainate-activated channels. This Ca2+ block gives rise to the outward rectification of the kainate responses.
Gu
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YP
Marine Biomedical Institute, University of Texas Medical Branch, Galveston 77550.
Huang
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LY
D000109:Acetylcholine / Q000494:pharmacology / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002469:Cell Separation; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D007608:Kainic Acid / Q000378:metabolism* / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D016202:N-Methylaspartate / Q000494:pharmacology / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D051381:Rats; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter / Q000187:drug effects* / Q000378:metabolism; D014276:Trigeminal Nerve / Q000166:cytology* / Q000187:drug effects / Q000502:physiology
D000109:Acetylcholine; D002118:Calcium; D007473:Ion Channels; D007608:Kainic Acid; D008274:Magnesium; D016202:N-Methylaspartate; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter