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Involvement of L‐Type‐Like Amino Acid Transporters in S ‐Nitrosocysteine‐Stimulated Noradrenaline Release in the Rat Hippocampus
Author(s) -
Satoh Souichi,
Kimura Tatsuo,
Toda Masahiro,
Maekawa Mutuko,
Ono Satoshi,
Narita Hirokazu,
Miyazaki Hiroyuki,
Murayama Toshihiko,
Nomura Yasuyuki
Publication year - 1997
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1997.69052197.x
Subject(s) - chemistry , leucine , phenylalanine , microdialysis , amino acid , methionine , arginine , biochemistry , extracellular
Abstract: Nitrogen oxides, such as nitric oxide, have been shown to regulate neuronal functions, including neurotransmitter release. We investigated the effect of S ‐nitroso‐ l ‐cysteine (SNC) on noradrenaline (NA) release in the rat hippocampus in vivo and in vitro. SNC stimulated [ 3 H]NA release from prelabeled hippocampal slices in a dose‐dependent manner. SNC stimulated endogenous NA release within 30 min to almost five times the basal level in vivo (microdialysis in freely moving rats). In a Na + ‐containing Tyrode's buffer, SNC‐stimulated [ 3 H]NA release was inhibited 30% by the coaddition of l ‐leucine. In the Na + ‐free, choline‐containing buffer, SNC‐stimulated [ 3 H]NA release, which was similar to that in the Na + ‐containing buffer, was inhibited markedly by l ‐leucine, l ‐alanine, l ‐methionine, l ‐phenylalanine, and l ‐tyrosine. The effects of the other amino acids examined were smaller or very limited. The effect of l ‐leucine was stronger than that of d ‐leucine. A specific inhibitor of the L‐type amino acid transporter, 2‐aminobicyclo[2.2.1]‐heptane‐2‐carboxylate (BCH), inhibited the effects of SNC on [ 3 H]NA release in the Na + ‐free buffer. Uptake of l ‐[ 3 H]leucine into the slices in the Na + ‐free buffer was inhibited by SNC, BCH, and l ‐phenylalanine, but not by l ‐lysine. The effect of SNC on cyclic GMP accumulation was not inhibited by l ‐leucine, although SNC stimulated cyclic GMP accumulation at concentrations up to 25 µ M , much less than the concentration that stimulates NA release. These findings suggest that SNC is incorporated into rat hippocampus via the L‐type‐like amino acid transporter, at least in Na + ‐free conditions, and that SNC stimulates NA release in vivo and in vitro in a cyclic GMP‐independent manner.