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pubmed:abstractText |
1. The in vitro effects of 6-hydroxydopamine (6-OHDA) and 5-hydroxydopamine (5-OHDA) on 3H-efflux from rabbit pulmonary artery after incubation with [3H]noradrenaline ([3H]NA) or [3H]adenosine were assessed. 2. 6-OHDA (100 microM) or 5-OHDA (100 microM) enhanced not only [3H]noradrenaline efflux, but also [3H]purines efflux. 3. Following Ca2+-removal, [3H]NA and [3H]purine effluxes evoked by these hydroxydopamines were moderately and considerably diminished, respectively. In addition, the 6-OHDA-evoked [3H]purine efflux was significantly decreased by W-7 (30 microM), a calmodulin inhibitor. 4. The 6-OHDA or 5-OHDA-evoked purine release was almost insensitive for prazosin (0.3 microM), indicating a neuronal release. 5. The peak [3H]purine efflux evoked by 6-OHDA or 5-OHDA occurred in the corresponding fraction number to that for the [3H]NA efflux. 6. These results suggest that 6-OHDA and 5-OHDA may expel NA together with purines from the amine stored sites (probably, in axoplasm) in the adrenergic nerves.
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