Characteristics of responses of isolated human fallopian tube to transmural stimulation and to sympathomimetic amines.

The responses of circular and longitudinal muscle of human fallopian tube to transmural stimulation and sympathomimetic amines have been investigated. It was found that tissues from the earlier part of the menstrual cycle (i.e., estrogen dominant) were less responsive to all stimuli than those from the middle or late phase of the cycle. Although excitatory alpha responses of ampulla and isthmus could be observed, the predominant response of ampulla and isthmus, in all phases of the menstrual cycle, to (--)-noradrenaline and transmural stimulation was inhibition of spontaneous activity. The inhibitory response to transmural stimulation, was abolished by tetrodotoxin and guanethidine. The inhibitory responses to transmural stimulation and (--)-noradrenaline were reversed by propranolol. These findings show that the response of tissues to transmural stimulation resulted from release of noradrenaline from adrenergic nerves, and subsequent action on inhibitory beta adrenergic receptors.