Myogenic peristalsis in isolated preparations of chicken oesophagus.

1. Nicotine, 20 mug/ml, briefly and partially blocked the longitudinal contractions of a chick vagus nerve-oesophagus preparation to nerve stimulation, but potentiated them in the presence of hyoscine, 10 mug/ml.2. Strychnine, 20 mug/ml, antagonized the longitudinal contractions of the chick oesophagus to nerve stimulation, though not to acetylcholine or 5-hydroxytryptamine. Hyoscine, 10 mug/ml, enhanced the nerve-blocking action of strychnine.3. These observations suggest that in the vagus nerve of the chicken, hyoscine either blocks certain types of fibre selectively or interacts with pharmacological receptors for strychnine and nicotine.4. Tetrodotoxin, 1 mug/ml, propranolol, 40 mug/ml, cocaine, 200 mug/ml, or strychnine, 100 mug/ml, which render autonomic nerves inexcitable, potentiated the spontaneous movements of isolated preparations of chicken oesophagus at normal intra-luminal pressure; they also potentiated peristaltic response to increased intra-luminal pressure.5. These observations suggest that the preparations contain intramural nerves that inhibit the musculature.6. Peristalsis in the chicken oesophagus was unaffected by nicotine, 20 mug/ml, tubocurarine, 20 mug/ml, hyoscine, 10 mug/ml, phentolamine, 1 mug/ml, propranolol, 0.5 mug/ml, mepyramine, 1 mug/ml, methysergide, 0.1 mug/ml, and morphine, 20 mug/ml. It was produced in preparations of chicken oesophagus after removal of the mucous membrane. Papaverine, 20 mug/ml, inhibited the peristalsis and had a spasmolytic action in the musculature.7. These observations suggest that the peristalsis in isolated preparations of chicken oesophagus is dependent solely upon myogenic contractility.