QUANTITATIVE MEASUREMENT OF UTERINE RESPONSES USING THE STRAIN GAGE DYNAMOMETER, WITH NOTES ON THE EFFECT OF ANTI-HISTAMINIC DRUGS ON THE RABBIT MYOMETRIUM

The myometriuxn of experimental animals is commonly employed to test oxytocic, spasmolytic or other musculotropic agents. In general, the uterus is used in one of two ways. Either the uterus is excised and immersed in oxy-genated physiological salt solution, or it is used in vivo in unanesthetized or anesthetized animals after suitable operative and technical preparation. Which-ever method is used, the effect of a drug, or a change in the physiological envi-ronment, is judged by simple inspection of the kymographic tracing of myometrial activity. The magnitude of the effect is estimated by noting the qualitative changes in tonus and frequency of rhythmic contractions. When the results are expressed quantitatively, it is usual to employ a series of + or- signs according to the judgment of the investigator or the reader. Clearly, the most useful method will be one which yields results calculable in terms of absolute force or percentage changes from a normal or control period of activity. In this paper, such a method is described. The key to the method is the use of the Statham strain gage dynamometer.