Calcium dependence of glutamate receptor-evoked alkaline shifts in hippocampus.
Glutamate receptor activation induces an extracellular alkalinization in rodent hippocampus. We studied its Ca2+ dependence and pharmacology in hippocampal slices. Glutamate-evoked alkaline shifts were blocked by 0 Ca2+ saline. Alkalinizations induced by AMPA (alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid) and NMDA (N-methyl-D-aspartate) were abolished by 20 microM CNQX (6-cyano-7-nitro-nitroquinoxaline-2,3-dione) and 50 microM APV (DL-2-amino-5-phosphonovalerate), respectively. The AMPA- and NMDA-evoked alkaline shifts were blocked by 0 Ca2+, however, AMPA-induced [K+]o elevation was unaffected. These data suggest that the glutamate receptor-channel does not mediate H+ influx, and support a role for Ca(2+)-H+ exchange.
Smith
S E
SE
Department of Physiology and Biophysics, New York University Medical Center, NY 10016.
Gottfried
J A
JA
Chen
J C
JC
Chesler
M
M
D000468:Alkalies / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D005110:Extracellular Space / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D006624:Hippocampus / Q000378:metabolism*; D066298:In Vitro Techniques; D016202:N-Methylaspartate / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D051381:Rats; D017470:Receptors, Glutamate / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D000468:Alkalies; D017470:Receptors, Glutamate; D018698:Glutamic Acid; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D011188:Potassium; D002118:Calcium