RECORDING AND ANALYSIS OF UTERINE ACTIVITY IN PREGNANT GUINEA-PIGS

Guinea-pigs are of considerable interest for the study of the physiolo gy of parturition in view of their lack of placental 17-alpha hydroxyl ase, a property which they share with Man and monkeys. To allow long-t erm analysis of uterine activity, a chronic guinea pig model was devel oped carrying a uterine electromyogram (EMG) electrode array, intraute rine and intraabdominal balloon catheters and vascular catheters. Oper ative procedures and the characteristics of the hardware and software are described and evaluated. Quantitative analysis of uterine activity relies on the quasi-integrated EMG signal which is highly correlated with the raw EMG signal. Under optimal conditions of intrauterine pres sure recording, the area of the quasi-integrated EMG signal is highly correlated with the area of the intrauterine pressure increment. The p reparation is stable for at least four weeks, measurements are reprodu cible, and biologically meaningful results are obtained from the recor dings.