ISSN:
1471-4159
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Medizin
Notizen:
Abstract: We investigated the relationships among N-methyl-d-aspartate, glycine, L-type voltage-dependent calcium channels, and [3H]dopamine release in a canine model of global cerebral ischemia/reperfusion. The binding of [3H]PN200-110 ([3H]isradipine) to L-type voltage-dependent calcium channels, that open as a consequence of N-methyl-d-aspartate-induced changes in membrane potential, was approximately doubled in striatal membranes prepared from ischemic animals relative to controls, and remained significantly elevated at 30 min and 2 h of reperfusion. These changes coincided temporally with changes in the ability of the voltage-sensitive calcium channel blocker nitrendipine to inhibit glycine enhancement of N-methyl-d-aspartate-stimulated [3H]dopamine release in striatal slices prepared from the same animals. Compared with nonischemic controls, N-methyl-d-aspartate-stimulated [3H]dopamine release was increased in ischemic animals and remained increased throughout reperfusion up to at least 24 h. Glycine enhanced N-methyl-d-aspartate-stimulated release in all treatment groups. The enhancement of N-methyl-d-aspartate-stimulated dopamine release by glycine was reduced by the inclusion of nitrendipine in striatal slices from ischemic and 30-min reperfused animals. These data suggest that glycine may facilitate opening of the voltage-dependent calcium channels activated by N-methyl-d-aspartate and that this facilitation is blocked by the antagonist nitrendipine.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1046/j.1471-4159.1994.63010215.x
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