Abstract
Although morphin is known to delay the progress of labor we have hitherto been unable to detect any inhibitory influence of this drug upon the tone or activity of the uterus in animals. It causes rather an increase in tone in the isolated uterus of cat and guinea pig, 1 and often in the intact uterus of the decerebrate cat or anesthetized rabbit. 2 The only inhibition of the uterus by morphin which we have observed previous to the present work has been accounted for by circulatory collapse.
Conditions of anesthesia or decerebration under which the morphin was given in our previous work have, by exclusion, led us to the belief that morphin, in clinical doses, inhibits uterine activity by a purely cerebral action. Desiring more direct evidence on this point we were led to inquire into the nature of cerebral control of the uterus, if any exists.
To this end we have begun by the employment of a method subjecting a part of the cortex and basal ganglia to the influence of cold and heat. This is done by means of a double metal tube fixed in the skull of a rabbit, on one side, anterior to the coronal suture and passing through the anterior portion of the corpus striatum to the base of the skull. The lateral ventricle is usually entered. This procedure, which was first employed by one of us in the study of cerebral control of body temperature, 1 is performed aseptically under light ether anesthesia. As soon as the animal is free from the narcotic certain cerebral functions may be influenced by the passage through the tube of hot or cold water.
The advantages of such a method are (I) the confinement of the effective agent entirely to the cerebrum (or a portion of it), (2) the absence of an anesthetic, and (3) the ease with which the functional activity of the brain can be quickly altered in either of two opposite directions.
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