Fig. 7.

Effects of β-NAD on spontaneously occurring contractile activity and twitch contractions of the circular muscle coat evoked by electrical field stimulation in human jejunum. A: spontaneous contractile activity and twitch response to electrical field stimulation in the absence of pharmacological agents (Control). B: exposure to β-NAD augmented spontaneous contractile activity and suppressed electrically evoked twitch response. C: the P2Y₁ receptor agonist MRS 2365 suppressed spontaneous contractile activity, but not the electrically evoked twitch response. D: action of β-NAD was unchanged by the presence of the P2Y₁ receptor antagonist MRS 2500. E: action of the P2Y₁ receptor agonist MRS 2365 was suppressed by the P2Y₁ receptor antagonist MRS 2500. F: ADP suppressed spontaneous contractile activity, but not the electrically evoked twitch response. G: exposure to the adenosine A₁ receptor agonist CCPA enhanced spontaneously occurring contractile activity and suppressed the electrically evoked twitch response. H: neural blockade by TTX enhanced spontaneously occurring contractile activity and suppressed the electrically evoked twitch response. I: action of the P2Y₁ receptor agonist MRS 2365 to suppress spontaneously occurring contractile activity was unaffected by TTX. J: absence of action of β-NAD applied in the presence of TTX.