DIRECT MEASUREMENT OF THE RELEASE OF ATP AND ITS MAJOR METABOLITES FROM THE NERVE-FIBERS OF THE GUINEA-PIG TAENIA-COLI

1. The release of adenosine triphosphate (ATP), adenosine diphosphate, adenosine monophosphate and adenosine from guinea-pig taenia coli in response to electrical stimulation of intramural nerves was measured d irectly using high performance liquid chromatography separation and fl uorometric detection. 2. Purines were released in a frequency-dependen t manner by trains of transmural electrical pulses at 1-30 Hz. 3. Elec trically evoked release of ATP was abolished by tetrodotoxin (10(-6) m ol/L) but was not affected by nicardipine (10(-6) mol/L). 4. The relea se of purines was reduced in the presence of atropine. 5. Pituitary ad enylyl cyclase-activating peptide did not evoke the release of any pur ines and did not modify the electrically evoked release of purines. 6. The results suggest that ATP and its major metabolites are released f rom a neuronal source, possibly the enteric inhibitory nerves, in the guinea-pig taenia coli.