Prostaglandins, antipyretic analgesics and adrenergic stimuli on the isolated artery

In untreated, and cocaine- and DOCA-treated rabbit ear arteries, PGE2 and arachidonic depressed to responses to intramural sympathetic nerve stimulation. Constrictor responses to extraluminal NA in the treated arteries were also depressed. A comparison of its inhibitory potency on the two types of responses suggest that the effects of arachidonic acid, but not PGE2 on adrenergic nerve stimuli, were selectively blocked by aspirin 200 mug/ml and by indomethacin 3 mu/ml. In these concentrations, aspirin, but not indomethacin, enhanced the magnitude of the resoonses to the stimuli. Aspirin also selectively reduced the inhibition by arachidonic acid of the response to extraluminal NA (tested in cocaine0 and DOCA-treated arteries).