The pharmacological nature of the response of the reserpinized guinea‐pig vas deferens to postganglionic nerve stimulation

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Abstract
1 . Intracellular recordings from single smooth muscle cells of the guinea-pig vas deferens have been made after depletion of neuronal stores of noradrenaline by chronic reserpine treatment. 2 . Junctional responses to postganglionic hypogastric nerve stimulation were depressed, but large excitatory junction potentials (EJPs) and action potentials could still be evoked by stimulation at 1–2 c/s. 3 . These junctional responses were not reduced by the presence of hyoscine (5 × 10−7g/ml.), but were greatly depressed by the presence of bretylium (2 × 10−6g/ml.). 4 . Even in the presence of bretylium, junctional responses leading to action potentials could still be evoked by using high voltages of stimulation. 5 . It is concluded that when neuronal noradrenaline stores have been depleted by reserpine some noradrenaline is still available for release by nerve stimulation. 6 . It is further concluded that if the non-adrenergic component of the response of the guinea-pig vas deferens to nerve stimulation is cholinergic, this component is resistant to blockade by hyoscine.