Characteristics of accumulation of ephedrine in rabbit atria.
The characteristics of uptake of (not equal to)-(beta-14C)ephedrine were studied in isolated rabbit atria. Ephedrine was rapidly accumulated against the concentration gradient. From 5 X 10-7 to 10-2 M, uptake occurred at a uniform initial rate. Uptake was slightly inhibited by high concentrations of ouabain, cocaine, desipramine, lidocaine and phenethylamines, and by a reduction in the external Na+ concentration. Uptake was not, however, reduced by omission of K+ from the medium, by metabolic inhibitors or by a variety of drugs known to inhibit the extraneuronal uptake and binding of noradrenaline. Pretreatment of animals with 6-hydroxydopamine very significantly reduced the uptake of (not equal to)-(3H)metaraminol, but did not alter the uptake of ephedrine. It was concluded that the uptake of ephedrine in rabbit atria occurred predominantly in extraneuronal tissues possibly as a result of passive diffusion followed by binding.
D000818:Animals; D000963:Antimetabolites / Q000494:pharmacology; D003042:Cocaine / Q000494:pharmacology; D003714:Denervation; D003891:Desipramine / Q000494:pharmacology; D004809:Ephedrine / Q000378:metabolism*; D006325:Heart Atria / Q000378:metabolism; D006892:Hydroxydopamines / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010627:Phenethylamines / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011817:Rabbits; D012964:Sodium / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D000963:Antimetabolites; D006892:Hydroxydopamines; D010627:Phenethylamines; D010042:Ouabain; D012964:Sodium; D004809:Ephedrine; D003042:Cocaine; D011188:Potassium; D003891:Desipramine