Direct evidence for concomitant release of noradrenaline, adenosine 5'-triphosphate and neuropeptide Y from sympathetic nerve supplying the guinea-pig vas deferens.

Concomitant release of noradrenaline (NA) (using tritium labelling), adenosine 5'-triphosphate (ATP) (using the luciferin-luciferase firefly technique) and neuropeptide Y (using the enzyme-linked immunosorbant assay) during electrical stimulation of the guinea-pig vas deferens has been demonstrated. In addition it has been shown: (1) that release of NA and ATP is unaffected following selective desensitization of the P2 (ATP)-purinoceptor by alpha, beta-methylene ATP and (2) that total block of contractile responses of the vas deferens to nerve stimulation by a combination of prazosin and alpha, beta-methylene ATP does not reduce the release of NA and ATP. These results are consistent with the hypothesis that NA, ATP and neuropeptide Y are released as co-transmitters or modulators in sympathetic nerves supplying the vas deferens.