Endogenous purines may modulate adrenergic neurotransmission in the human fallopian tube

In the present investigation we have examined the possibility that endogenous purines may act as neuromodulatory agents in the human fallopian tube, using the selective adenosine receptor antagonist 8-p-sulfophenyltheophylline (PSOT). PSOT applied to untreated preparations enhanced the contractile responses to transmural nerve stimulation in the human fallopian tube, both in the secretory and proliferative hormonal phases. Furthermore, PSOT enhanced nerve-induced [3H]noradrenaline release during both hormonal phases. This can be taken as indirect evidence that endogenous purines inhibited the adrenergic neuroeffector transmission under the experimental conditions. The inhibitory effect presumably was exerted at both pre- and postjunctional adenosine receptors.