THE INFLUENCE OF TONAL CONDITIONS ON THE MUSCULAR RESPONSE OF THE MONKEY'S STOMACH

¹ The Department of Physiology, Detroit College of Medicine and Surgery, Detroit

1. Stimulation of the central portion of the sciatic in the monkey results in either an augmentation or an inhibition of the stomach, the reaction appearing to be primarily dependent upon the pre-existing state of tonus of the gastric mechanism. If the stomach is hypertonic, reflex inhibition will follow central stimulation of this nerve; if hypotonic, a contraction may occur or there may be a definite increase in the tonus.

2. Stimulation of the peripheral end of either vagus produces a somewhat similar inhibitory or augmentory action, depending upon the degree of gastric tonus.

3. Peripheral splanchnic stimulation also exerts a similar but smaller response.

4. There is evidence that stimulation of the central portions of the vagus and splanchnic nerves produces, under certain conditions at least, a reflex inhibition of the gastric tonus.

5. Compression of the eyeball leads in some animals to the production of an oculogastric reflex and the tonus change is dependent upon the state of tonicity of the stomach.

6. It is possible that stimulation of all sensory nerves in the body exerts an influence on the stomach via long reflex mechanisms of the vagus and splanchnic efferents.

7. The gastric response is dependent upon the pre-existing state of tonus of the gastro-neuro-muscular mechanism. Tonus and movement are both involved and these may vary quite independently of each other.