No abstract

Summary1. The actions of morphine were studied on the segmental reflex of the decerebrate-spinal cat. Morphine decreased arterial blood pressure. 2. Morphine inhibited mono-and polysynaptic reflexes. The influence of morphine on monosynaptic reflexes was more obvious at stimulation of the dorsal root at a frequency of 12-5 Hz than at 0 5 or 2-5 Hz.3. The total amount of activity recorded from the ventral root after morphine depended on whether or not the evoked reflex was maximal or submaximal. 4. These actions of morphine were antagonized by naloxone. IntroductionThere is disagreement in the literature regarding the actions of morphine on cat spinal cord (Wikler, 1945; Takagi, Matsumura, Yanai & Ogiu, 1955). This communication relates experiments in which we have re-opened the question by studying the actions of morphine on the evoked electrical response of the segmental reflex of the low spinal cat and determining the influence of the magnitude of the evoked response and of stimulus repetition rate.

No abstract