Abstract
Electrical stimulation of the perivascular nerves of the guinea-pig saphenous artery elicited excitatory junction potentials (e.j.ps) in the smooth muscle cells. These e.j.ps were inhibited by arylazido aminopropionyl adenosine triphosphate (ANAPP3), a specific antagonist for the P2-purinoceptor, suggesting that ATP may be the neurotransmitter.