ROLE OF INTRINSIC, NON-ADRENERGIC, NON-CHOLINERGIC INHIBITORY NERVES IN THE REGULATION OF DISTENSIBILITY OF THE GUINEA-PIG COLON

1. The lengthening responses of segments of distal colon of guinea-pigs to applied weights were measured. 2. Distensibility was reduced by tetrodotoxin and quinidine; increased by atropine and hyoscine, and unaffected by guanethidine and phentolamine. 3. Tension changes produced by controlled stretches were increased by tetrodotoxin. 4. These results suggest that there is a net, inhibitory, non-adrenergic, non-cholinergic influence acting on the muscle during stretch against a background of cholinergic excitatory tone. This inhibitory activity may be activated reflexly by stretch. © 1979 Springer-Verlag.