EFFECT ON INTESTINAL MOTILITY OF CYCLOPROPANE ANAESTHESIA ALONE AND AFTER MORPHINE-SCOPOLAMINE PREMEDICATION

¹ From the Departments of Physiology and Anaesthesia, University of Wisconsin, Madison

Morphine produces a rise in the tonus and an increase in both the propulsive and non-propulsive movements of the dog intestine. The augmentation of propulsive movements, however, is followed within 10 to 20 minutes by a period during which propulsive movements are virtually absent. During this period the tonus is still high and non-propulsive movements are above normal amplitude. These results confirm studies by other investigators.

Scopolamine produces in a few minutes complete inhibition of movements and decreased tonus of the dog intestine. The inhibition lasts one to two hours.

Morphine and scopolamine, administered together, produce an effect on the intestinal movements essentially the same as the effect of morphine alone.

Cyclopropane anaesthesia, in the absence of both operative trauma and struggling, causes a decrease in the tonus and inhibits all types of movement in the intestine of the unpremedicated dog. In the lower planes of the third stage the inhibition is complete.

When the intestine is under the influence of morphine and scopolamine, cyclopropane anaesthesia does not lower the high tonus, and only partially inhibits the non-propulsive movements even in the fourth stage. Propulsive movements are absent.

After cessation of cyclopropane anaesthesia the non-propulsive movements return immediately to the pre-anaesthetic level; tonus recovery is rapid; recovery of propulsive movements may be immediate or may require several hours in either the premedicated or the unpremedicated animals.

An intestine-inhibiting substance is in circulation during cyclopropane anaesthesia, for denervated fistulae may be completely inhibited. That the inhibitory substance is cyclopropane itself has not been demonstrated.