Release of purines and noradrenaline from the vascular adrenergic nerves by 5- and 6-hydroxydopamine.
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.
D000241:Adenosine; D000818:Animals; D002118:Calcium / Q000502:physiology; D015283:Citalopram; D006892:Hydroxydopamines / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D016627:Oxidopamine; D011189:Potassium Chloride / Q000494:pharmacology; D011437:Propylamines / Q000494:pharmacology; D011651:Pulmonary Artery / Q000378:metabolism; D011687:Purines / Q000378:metabolism*; D011817:Rabbits; D012702:Serotonin Antagonists / Q000494:pharmacology
D006892:Hydroxydopamines; D011437:Propylamines; D011687:Purines; D012702:Serotonin Antagonists; D015283:Citalopram; C027802:5-hydroxydopamine; D011189:Potassium Chloride; D016627:Oxidopamine; D000241:Adenosine; D002118:Calcium; D009638:Norepinephrine