Sodium sensitive active transport of bretylium into adrenergic neurons for the development of blockade in rabbit ileum.

Transport of bretylium into adrenergic neurons was studied, using rabbit isolated periarterial nerve ileum preparations, by determining the effects of various incubation procedures, which inhibit noradrenaline uptake, to prevent or reverse the blockade. Adrenergic neuron blockade by bretylium 5 X 10(-5) (g/ml) was prevented but not reversed by incubation with sodium free and low temperature (10 degrees C) media. Ouabain 2.2 X 10(-8) and anoxia prevented bretylium-induced blockade. Noradrenaline 5 X 10(-6) and 8 X 10(-5) prevented and also reversed the blockade, but the reversing effect was transient. High calcium (totally 10 mM) readily reversed the bretylium-induced blockade, the recovery being complete and long-lasting. In light of the results, a sodium sensitive active transport of bretylium into adrenergic neurons is apparently necessary for development of adrenergic neuron blocking action in rabbit ilea.