The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

The various configurations of externally recorded slow waves from the small intestine of the cat are compared to those recorded intracellularly. It is shown that the slow waves represent periodic depolarizations of longitudinal muscle cells and that the flow of current associated with these depolarizations is similar to that in a core conductor. By recording monopolarly from a segment of intestine immersed in a volume conductor, slow waves are obtained having configurations ranging from those approximating the true time course and polarity of the intracellular slow wave to those approximating its second time derivative. This is shown to be a function of the pressure exerted by the electrode on the tissue. From a consideration of these results, plus those recently obtained by others, it is suggested that both "propagation" and synchronization of slow waves are manifestations of a modulation of slow wave discharge brought about either by electrotonic spread of current via low resistance intercellular pathways, or by voltage field effects.

Circular muscle from cat intestine exhibits spontaneous rhythmical contractions only when it is attached to longitudinal muscle. Under these conditions electrical slow waves can be recorded from circular muscle, but they disappear following complete removal of the longitudinal layer. If a small patch of longitudinal muscle remains, slow waves can be recorded from adjacent circular muscle. Those recorded lateral to the longitudinal layer are synchronized with slow waves recorded directly from this layer. Their amplitude decreases exponentially with distance, approaching zero at about 12 mm from the lateral edges and about 3 mm from the oral or aboral edge of the longitudinal layer. Slow waves can also be recorded across the entire intestinal wall or across a longitudinal-circular muscle preparation. With this method of recording, the amplitude of the slow waves decreases as the thickness of the circular layer is reduced by stripping away its innermost layers. The amplitude is not increased by replacing these layers. These results indicate that slow waves may be transmitted electrotonically from longitudinal to circular muscle, implying the existence of electrical continuity between the two muscle layers. The transmission of slow waves can account for the coordinated spontaneous rhythmicity exhibited by circular muscle under normal conditions, i.e., when attached to the longitudinal layer.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

The electrical and mechanical activities of the gastroduodenal junction were studied in isolated cat preparations, using the pressure-electrode technique. The spontaneous electrical activity of the pyloric antrum consists of periodic depolarizations, the configuration of which is somewhat more complex than that of comparable potentials recorded from the longitudinal muscle layer of the small intestine. Like their intestinal counterparts these antral slow waves may be associated with spike potentials which are thought to initiate contractions. The electrical activity at the gastroduodenal junction consists of a combination of antral and duodenal slow waves, sometimes accompanied by spike potentials. In the proximal duodenum, antral slow waves are represented by periodic depolarizations which may be associated with spike potentials followed by contractions. Because of the extension of the antral slow waves into the proximal duodenum, contractions initiated in the antrum may also extend into the proximal duodenum. It is concluded that the gastroduodenal junction is a transition zone, coordinating the electrical and corresponding mechanical activities of the antrum and proximal duodenum.

In order to determine whether or not atropine, procaine, and tetrodotoxin (TTX) can stimulate intestinal smooth muscle directly, we examined the effects of these drugs on the mechanical and electrical activities of several types of cat intestinal smooth muscle preparations. The preparations consisted of isolated rings of 1) intact intestinal wall, 2) intact longitudinal and circular muscle, 3) ganglion-free circular muscle, and 4) ganglion-free circular muscle devoid of its dense layer and plexus muscularis profundus. Atropine and procaine (greater than 10(-4) M) stimulated all four types of preparation. On the other hand, TTX (up to 5 X 10(-6) M) stimulated only preparations 1 and 2. It is concluded that whereas atropine and procaine can directly stimulate intestinal smooth muscle, the excitatory effect of TTX is neurally mediated.