Abstract
KCl (20-100 mM) and N-methyl-D-aspartate (NMDA, 100-1,000 microM) produce concomitant concentration-dependent increases in the release of previously captured [14C]acetylcholine and [3H]spermidine from rat striatal slices in vitro. The effects of NMDA (300 microM) on striatal [14C]acetylcholine and [3H]spermidine release were blocked with equal potencies by the competitive NMDA antagonist CGP 37849, the glycine site antagonist L-689,560, and the NMDA channel blocker dizocilpine. In contrast, although NMDA-evoked [14C]acetylcholine release was antagonized by ifenprodil (IC50 = 5.3 microM) and MgCl2 (IC50 = 200 microM), neither compound antagonized the NMDA-evoked release of [3H]spermidine at concentrations up to 100 microM (ifenprodil) or 1 mM (MgCl2). Distinct NMDA receptor subtypes with different sensitivities to magnesium and ifenprodil therefore exist in the rat striatum.
MeSH terms
-
2-Amino-5-phosphonovalerate / analogs & derivatives
-
2-Amino-5-phosphonovalerate / pharmacology
-
Acetylcholine / metabolism*
-
Aminoquinolines / pharmacology
-
Animals
-
Carbon Radioisotopes
-
Corpus Striatum / drug effects
-
Corpus Striatum / metabolism*
-
Dizocilpine Maleate / pharmacology
-
Dose-Response Relationship, Drug
-
In Vitro Techniques
-
Kinetics
-
Magnesium / pharmacology*
-
Magnesium Chloride / pharmacology
-
N-Methylaspartate / antagonists & inhibitors
-
N-Methylaspartate / pharmacology*
-
Piperidines / pharmacology*
-
Rats
-
Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
-
Receptors, N-Methyl-D-Aspartate / drug effects
-
Receptors, N-Methyl-D-Aspartate / physiology*
-
Spermidine / metabolism*
-
Tritium
Substances
-
Aminoquinolines
-
Carbon Radioisotopes
-
Piperidines
-
Receptors, N-Methyl-D-Aspartate
-
Magnesium Chloride
-
Tritium
-
2-amino-4-methyl-5-phosphono-3-pentenoic acid
-
4-trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4-tetrahydroquinoline
-
N-Methylaspartate
-
Dizocilpine Maleate
-
2-Amino-5-phosphonovalerate
-
Magnesium
-
Acetylcholine
-
ifenprodil
-
Spermidine