Effect of adrenergic and cholinergic drugs on the noradrenergic transmission in bladder neck smooth muscle.

Strips of bladder neck smooth muscle were isolated from the dog and noradrenaline stores in the peripheral sympathetic nerve terminals were labelled with (-)3H-noradrenaline. Transmural electrical stimulation was applied and the released radiolabeled noradrenaline in the superfusate was measured with a liquid scintillation counter. Autonomic drugs were administered in the superfusate to examine their effect on noradrenaline release evoked by electrical stimulation. The general conclusions drawn from the data are that: there are two autonomic receptor systems on sympathetic nerve terminals of bladder neck--alpha-adrenergic receptors and muscarinic receptors, the activation of alpha-adrenergic receptors or muscarinic receptors depresses noradrenaline release and parasympathetic nerve excitement inhibits noradrenaline release in bladder neck.