In vitro demonstration of seasonal transition effect on acetylcholine liberation from Auerbach's plexus of non-hibernator

Acetylcholine release from Auerbach's plexus of guinea-pig ileum, in vitro, both spontaneous and evoked by field-stimulation, responds to the seasonal transition from the spring to close to the beginning of summer. It did not change during the summer, however, tended to be higher than during the initial period (3 weeks after the beginning of spring).