Release of purines and noradrenaline by ouabain and potassium chloride from vascular adrenergic nerves.
1 Release of [3H]-noradrenaline and 3H-purine by ouabain (10(-4)M) or high KCl (50 mM) was investigated in the superfused rabbit pulmonary arterial segment preincubated with [3H]-noradrenaline or [3H]-adenosine. 2 Ouabain elicited a delayed large contraction and a parallel [3H]-noradrenaline efflux. These were substantially inhibited by Ca2+-free medium or preincubation with 6-hydroxydopamine (30 micrograms/ml, 30 min). 3 Ouabain caused an 3H-purine efflux which was slower than the [3H]-noradrenaline efflux. This was inhibited by 6-hydroxydopamine and in part by phentolamine (3 X 10(-6)M), indicating both neuronal and extraneuronal origins of purines. 4 In contrast to ouabain, high KCl appeared to induce predominantly purine efflux, which was phentolamine-insensitive and 6-hydroxydopamine-sensitive, indicative of neuronal origin. 5 It is suggested that the purine efflux evoked by ouabain and high KCl may originate from different neuronal vesicles.
D000818:Animals; D001808:Blood Vessels / Q000294:innervation*; D006892:Hydroxydopamines / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology*; D010646:Phentolamine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology*; D011687:Purines / Q000378:metabolism*; D011817:Rabbits; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000378:metabolism*
D006892:Hydroxydopamines; D011687:Purines; D010042:Ouabain; D011189:Potassium Chloride; D009638:Norepinephrine; D010646:Phentolamine