Effects of lowering [Na+]o and [K+]o and of ouabain on quisqualate-induced ionic changes in area CA1 of rat hippocampal slices.
Changes in extracellular ([Na+]o) and calcium ([Ca2+]o) concentration evoked by quisqualate (Quis), applied iontophoretically, were measured in rat hippocampal slices. Following an initial decrease in [Ca2+]o, Quis causes a post-application overshoot, which may reflect Ca2+ extrusion from cells by the Na+/Ca2+ exchanger. To test this hypothesis, the effects of directly and indirectly reduced transmembrane Na+ gradients on these Quis-induced Ca2+ overshoots were investigated. In all cases the post-application overshoots were reduced. This suggests that the Na+/Ca2+ exchanger is involved in the production of these Quis-induced Ca2+ overshoots which may have important implications for understanding how various types of glutamate receptors differ in their capability to trigger Ca2(+)-activated processes.
Stabel
J
J
Institut für Neurophysiologie, Universität zu Köln, Cologne, F.R.G.
Arens
J
J
Lambert
J D
JD
Heinemann
U
U
D000818:Animals; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D010042:Ouabain / Q000494:pharmacology*; D010069:Oxadiazoles / Q000494:pharmacology*; D011188:Potassium / Q000502:physiology*; D016318:Quisqualic Acid; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000502:physiology*
D010069:Oxadiazoles; D010042:Ouabain; D016318:Quisqualic Acid; D012964:Sodium; D011188:Potassium