Calcium directly permeates kainate/alpha-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid receptors in cultured cerebellar Purkinje neurons.
In cultures of rat cerebellar neurons that were enriched in Purkinje cells, the non-N-methyl-D-aspartate glutamate receptor agonist kainate (KA) stimulated Ca2+ influx into all neurons in Na(+)-containing solutions. A large Ca2+ influx was also observed in most neurons when KA was applied in Na(+)-free solutions, even when the cells were voltage-clamped at negative potentials. KA also stimulated Co2+ uptake into both Purkinje and non-Purkinje neurons. The KA-induced Ca2+ influx was insensitive to pharmacological antagonists of voltage-sensitive Ca2+ channels and antagonists of N-methyl-D-aspartate receptors. Thus, different types of cerebellar neurons possess KA-gated ionophores that are permeable to Ca2+. This Ca2+ conductance may play an important role in glutamate-mediated physiological and pathological events in the cerebellum.
Brorson
J R
JR
Department of Pharmacological and Physiological Sciences, University of Chicago, Illinois 60637.
Bleakman
D
D
Chard
P S
PS
Miller
R J
RJ
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D005455:Fluorescent Antibody Technique; D007051:Ibotenic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D007608:Kainic Acid / Q000378:metabolism*; D008564:Membrane Potentials; D011689:Purkinje Cells / Q000378:metabolism* / Q000502:physiology; D051381:Rats; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid
D002118:Calcium; D007051:Ibotenic Acid; D007608:Kainic Acid; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid