Suramin and the inhibitory junction potential in taenia caeci of the guinea-pig.

The effect of surinam on the inhibitory junction potential evoked in smooth muscle cells of guinea-pig taenia caeci by stimulation of intramural nerves at 22 degrees C was investigated. The amplitude of the inhibitory junction potential was reduced concentration dependently by suramin. The suppression of this response by suramin became less pronounced when the number of stimuli increased (pulse rate: 20/s). These results indicate that suramin reduces the inhibitory junction response by interacting with P2-purinoceptors.