On the Behavior of the Respiratory Muscles During Vomiting

In order to produce vomiting in the dogs decerebrated and unanesthetized, apomorphine or copper sulfate was administered. The behaviors of both the inspiratory and the expiratory muscles were studied through the course of the act of vomiting by the electromyographic technique. The results are summarized as follows: (1) The most significant signs of vomiting seems to be the recurrent vomiting volleys from the vomiting center each of which is produced abruptly and transiently. (2) The peculiarities of the vomitng volley consist in the simultaneous discharges of both the inspiratory and the expiratory muscles, resulting in the so-called retching movement. (3) The vomiting volleys, in their rhythm, seem to arise independent of the respiratory center, but the former are capable of affecting the respiratory centers at any respiratory phase. (4) The acceleration of the breathings observed prior to the retching seems to be due to the invigorated activity of the respiratory centers affected directly by the administration of the vomiting agents without an intermediate step by the vomiting centers. (5) The simultaneous contraction of the diaphragm and the abdominal muscles are merely a component of a peculiar type of the respiratory movements, namely, that of the retching. (6) The glottis muscles are, however, ruled out from the principle described in (2): the closer of the glottis muscles contracts during the retching, while the opener is completely inhibited.</p

The action of atropine and acetylcholine on the pace maker ganglion cells of limulus heart

On the median nerve trunk-heart muscle preparation of Limulus the authors studied the effects of atropine and acetylcholine upon the pace maker ganglion cells. The results are summarized as follows: (1) Atropine exerts an excitatory action on the pace maker ganglion cells in a concentration of 1-2 per cent. resulting in an increase of the heart rate. No effect is recognized on the heart beats, where the drug is applied to the heart muscle. (2) Acetylcholine exerts an excitatory action in a lower concentration (0.001-0.10 %) and produces a transitory excitation followed by an inhibition in a higher concentration (1-5 %). No effect is perceptible on the heart beats, when the drug is applied to the heart muscle. (3) Where atropine has been previously applied to the median nerve trunk, acetylcholine applied to the same spot produces always an inhibition of the heart beats. Conversely, when the ganglion cells activated previously by acetylcholine, a subsequent administration of atropine suppresses the activity of the ganglion cells, resulting in an inhibition of the heart beats.</p

A Factor Condition­ing the Inhibitory Response of the Intestinal Motility to the Peripheral Stimulation of the Cervical Vagus Nerves

Recording the motility of the stomach as well as the small intestine by the balloon method in the dogs decerebrated and unanesthetized, we found a factor conditioning the inhibitory effect of the intestinal motility to the stimulation of the perpheral cut-end of cervical vagus nerves. The results may be summarized as follows: (1) The stimulation of the peripheral cut-end of the cervical vagus nerve frequently produces the yarious patterns and degrees of inhibition of the intestinal motility of the stomach as well as of the small intestine. (2) The inhibitory effect still appears after the severing of the vagus nerves at the caudal end of the esophagus, but is obliterated and reversed to the augmentory when the splanchnic nerves are bilaterally severed. (3) The cause of the inhibition is attributable to the strong excitation of the intestinal inhibitory centers brought about by the central stimulating action of the anoxemia resulting from the stimulation of the cervical vagus nerves, and the reversal of the response is due to the peripheral stimulating action of the anoxemia upon the intestinal muscles, its central action being excluded from the action on the intestine by the severing of the splanchnic nerves.</p

On the intestinal extrinsic reflexes elicited from the small in­testine

Effects of stimulation of the small intestine upon the gastric, small intestinal and colonic motility have been studied in dogs. The results are summarized as follows. 1. The movements of the stomach, small intestine, and proximal colon are always inhibited by the distension or the contracture of the muscular coats of the small intestine but no responses are produced by a mechanical or chemical stimulation of the mucosa; and those of the distal colon are in most cases also inhibited, whereas in rare instances are they augmented. 2. The afferent impulses are transmitted through the great and small splanchnic nerves and the lumbar sympathetic nerves to the inhibitory as well as the excitatory (pelvic nuclei) centers of the intestinal movements located within the spinal cord, whereas the vagal nuclei remain unaffected. The efferent impulses are transmitted through the thoraco-lumbar sympathetic nerves as well as through the pelvic nerves. The latter are involved in the augmentative effect produced in the distal colon. 3. The threshold producing the extrinsic muscular reflex is higher than that eliciting the intrinsic muscular reflex.</p