Theophylline‐sensitive modulation of non‐cholinergic excitatory neurotransmission in the guinea‐pig ileum

Abstract

Atropine‐resistant longitudinal contractions of the guinea‐pig ileum due to field stimulation were greatly augmented by theophylline (150 μM). Adenosine exerted an opposite effect. Theophylline did not potentiate contractions evoked by exogenous substance P. It is suggested that a theophylline‐sensitive inhibitory mechanism (possibly mediated by adenosine or a related substance) controls transmitter release from enteric non‐cholinergic excitatory neurones. 1985 British Pharmacological Society