title: The extent of neuronal re-uptake of 3H-noradrenaline in isolated vasa deferentia and atria of the rat.
abstract: After pretreatment of rats with reserpine and pargyline (to inhibit vesicular uptake and monoamine oxidase, respectively) and after inhibition of catechol-O-methyl transferase (by U-0521) and in calcium-free solution, the adrenergic neurones of isolated vasa deferentia and atria were loaded with 3H-noradrenaline. The spontaneous efflux of 3H-noradrenaline and 3H-dihydroxyphenylglycol was determined, as well as the steady-state effect of two concentrations of desipramine. On the basis of a mathematical model of the adrenergic nerve ending, fractional rates (FR = rate of flux divided by tissue tritium content) were calculated for unidirectional outward diffusion, for outward transport and for neuronal re-uptake (all for 3H-noradrenaline). Although the density of adrenergic innervation is lower in atria than in vasa deferentia, neuronal re-uptake amounted to about 90% of the spontaneous efflux of 3H-noradrenaline in both tissues. While the FR for unidirectional outward diffusion was virtually the same in both tissues, the FR for outward transport of 3H-noradrenaline was more than three times higher in atria than in vasa deferentia. There is, as yet, no explanation for this pronounced difference.
authors.affiliation: Institut für Pharmacokologie und Toxikologie, Universität Würzburg, Federal Republic of Germany.
authors.forename: E
authors.initials: E
authors.lastname: Schömig
authors.forename: P
authors.initials: P
authors.lastname: Fischer
authors.forename: C L
authors.initials: CL
authors.lastname: Schönfeld
authors.forename: U
authors.initials: U
authors.lastname: Trendelenburg
mesh_terms: D000818:Animals; D003891:Desipramine / Q000494:pharmacology; D006325:Heart Atria / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009474:Neurons / Q000378:metabolism*; D009638:Norepinephrine / Q000493:pharmacokinetics*; D051381:Rats; D011919:Rats, Inbred Strains; D009435:Synaptic Transmission / Q000187:drug effects*; D014316:Tritium; D014649:Vas Deferens / Q000378:metabolism*
chemical_list: D014316:Tritium; D003891:Desipramine; D009638:Norepinephrine