title: The presynaptic effects of aspirin and prostaglandin E2 in the isolated cat heart.
abstract: The presynaptic effects of aspirin and prostaglandin E2 (PGE2) were evaluated in the isolated perfused cat heart preparation. Tissue catecholamine stores were studied by labelling the sympathetic nerve endings with [3H]-noradrenaline ([3H]-NA) and the effect of electric neural stimulation (5 Hz, 0.5 ms, 8 V, 60 s) was determined in the presence of drugs which inhibit neuronal or extraneuronal uptake, or antagonize alpha-adrenoceptors. [3H]-NA overflow was significantly increased by electric neural stimulation. Perfusion with 0.1 microM phentolamine increased transmitter overflow. Infusion of 0.1 microM PGE2 reduced the [3H]-NA overflow induced by electrical stimulation. Administration of 1 microM aspirin increased the [3H]-NA overflow and PGE2 prevented this effect of aspirin. The results support the view that PGEs participate in the negative feedback of transmitter release in the isolated perfused cat heart.
mesh_terms: D000818:Animals; D001241:Aspirin / Q000494:pharmacology*; D002415:Cats; D003891:Desipramine / Q000494:pharmacology; D015232:Dinoprostone; D004558:Electric Stimulation; D006321:Heart / Q000187:drug effects*; D009638:Norepinephrine / Q000378:metabolism*; D009647:Normetanephrine / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011458:Prostaglandins E / Q000494:pharmacology*; D017981:Receptors, Neurotransmitter / Q000187:drug effects*
chemical_list: D011458:Prostaglandins E; D017981:Receptors, Neurotransmitter; D009647:Normetanephrine; D015232:Dinoprostone; D001241:Aspirin; D003891:Desipramine; D009638:Norepinephrine; D010646:Phentolamine