Further evidence for adrenergic transmission in the human vas deferens.

1. Isolated portions of human vas deferens responded to field stimulation of the intramural nerve fibres or to exogenously applied noradrenaline with rhythmical contractions of both longitudinal and circular muscle layers. 2. In guinea-pig and rabbit vas deferens field stimulation produced an initial rapid 'twitch' response which was not found with human vasa. 3. Responses of the human vas to field stimulation were depressed by the alpha-adrenoceptor blocking agents phentolamine and yohimbine. 4. It is concluded that the motor innervation of the human vas deferens is adrenergic and the relevance of this to the physiological operation of the tissue is discussed.