Effect of noradrenaline reuptake blockade on evoked tritium overflow from mouse vasa deferentia and rat cortex slices previously incubated with 3H-noradrenaline.
1 Electrical stimulation of mouse vasa deferentia or of rat occipital cortex slices which had been previously incubated with 3H-(-)noradrenaline increased the overflow of tritium from the tissue above that occurring spontaneously. 2 Phentolamine (10 micrometers) increased evoked tritium overflow from vasa deferentia as did both phentolamine and yohimbine (1.25 micrometers) when applied to cortex slices. 3 Evoked tritium overflow from cortex slices was increased by cocaine (20 micrometers) but neither cocaine (11 micrometers) nor desmethylimipramine (0.5 micrometers) increased evoked tritium overflow significantly in the vas deferens. 4 In contrast to its effect when applied alone, in the presence of phentolamine, cocaine produced a further increase in evoked tritium overflow in both tissues. 5 Application of (-)-noradrenaline in the presence of cocaine produced a reduction in evoked tritium overflow which was quantitatively similar in both tissues. 6 It is suggested that the effect on tritium overflow of blockade of the reuptake of noradrenaline by cocaine is masked in mouse vas deferens by a compensatory process mediated through presynaptic alpha-adrenoreceptors. 7 It may be that such a compensation does not occur in cortex slices because of a difference in the architecture of the synapse in this tissue.
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D003042:Cocaine / Q000494:pharmacology; D004347:Drug Interactions; D004558:Electric Stimulation; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009130:Muscle, Smooth / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D010646:Phentolamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014649:Vas Deferens / Q000378:metabolism
D003042:Cocaine; D009638:Norepinephrine; D010646:Phentolamine