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Regulation of [3H]norepinephrine release by N-methyl-D-aspartate receptors in minislices from the dentate gyrus and the CA1-CA3 area of the rat hippocampus

1993; Elsevier BV; Volume: 46; Issue: 11 Linguagem: Inglês

10.1016/0006-2952(93)90640-i

1873-2968

Marı́a Estela Andrés, Gonzalo Bustos, Katia Gysling,

Ion channel regulation and function

It has been reported previously that N-methyl-d-aspartic acid induces a significant release of [3H]norepinephrine preaccumulated in slices from the hippocampus. In the present study, we investigated whether there are regional differences in the hippocampus regarding this N-methyl-d-aspartate effect. In the absence of Mg2+, N-methyl-d-aspartate (10–200 μM) induced the release of [3H]norepinephrine from superfused minislices containing the dentate gyrus area or the CA1-CA3 region of the hippocampus. Such N-methyl-D-aspartate effects on [3H]norepinephrine release were significantly higher in the dentate gyrus than in the CA1-CA3 area. The N-methyl-d-aspartate effects in both hippocampal areas were also reduced significantly by d-2-amino-5-phosphonovaleric acid (50 μM), an antagonist of the N-methyl-d-aspartate receptor, and by tetrodotoxin, a blocker of the voltage-dependent Na+ channels. The extent of this reduction was the same in the dentate gyrus and the CA1-CA3 area. Further experiments, conducted in the presence of Mg2+, demonstrated that N-methyl-d-aspartic acid increased K+-induced release of [3H]norepinephrine from dentate gyrus minislices but not from the CA1-CA2 area. The results are consistent with the existence of a higher density and/or different subtypes of N-methyl-d-aspartate receptors modulating [3H]norepinephrine release in the dentate gyrus as compared with the CA1-CA3 hippocampal area.