title: GABA-receptor stimulation enhances norepinephrine-induced polyphosphoinositide metabolism in rat hippocampal slices.
abstract: The effect of gamma-aminobutyric acid (GABA)receptor stimulation on norepinephrine (NE)-induced metabolism of polyphosphoinositides (PIPs) was studied in rat hippocampal slices. Inositol phosphates (IPs), PIPs, and phosphatidic acid were measured. NE induced formation of IPs and phosphatidic acid in a dose-dependent manner with an EC50 of 4.5 microM. GABA, 3-aminopropanesulphonic acid (3APS) and muscimol did not affect PIPs breakdown, but they strongly increased (greater than 100%) PIPs metabolism induced by 1 microM NE. Their action was antagonized by bicuculline (10 microM). We discuss the implications of these findings in hippocampal neurotransmission.
mesh_terms: D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D009638:Norepinephrine / Q000494:pharmacology*; D010712:Phosphatidic Acids / Q000378:metabolism; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D013654:Taurine / Q000031:analogs & derivatives / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
chemical_list: D007295:Inositol Phosphates; D010712:Phosphatidic Acids; D018129:Phosphatidylinositol Phosphates; D010716:Phosphatidylinositols; D011963:Receptors, GABA-A; D013654:Taurine; D009118:Muscimol; D005680:gamma-Aminobutyric Acid; C001355:tramiprosate; D009638:Norepinephrine; D001640:Bicuculline