An experimental model for long-term examinations of urethral and uterine pressures in conscious dogs: effect of a highly selective compound contracting urethral smooth muscles.

An experiment model was designed for studies of urethral and uterine pressures in a conscious animal, thereby avoiding the interference of anesthesia on these responses. Dogs were trained to stand in cradles for an experimental period of 3 hours, during which urethral and uterine pressures and ECG were recorded. Substances were administered either orally or intravenously. Intravenously given phenylpropanolamine (PPA; 0.3 mg./kg.) and a newly synthetized compound S113 (0.5 mg./kg. intravenously) increased the urethral pressure by about 30 and 100%, respectively. Oral administration of PPA (3.5 mg./kg.) and S113 (6 mg./kg.) increased it by about 60 and 85%, respectively. In contrast to PPA, S113 evoked no cardiac effects. Whereas PPA had pronounced effects on uterine contractility, S113 had only minor effects. Furthermore, the responses in the experiments were stable and reproducible. This dog model seems to be useful for long-term recordings of urethral and uterine pressures.