Abstract
It has been reported that isoxsuprine hydrochloride elicits smooth muscle relaxation but its mode of action does not involve the nervous system. We evaluated the effects of isoxsuprine administered in combination with ether or pentobarbital anesthesia. The ICR strain of male mice, 5 to 7 weeks old, were used in this series of experiments. Other experimental conditions were maintenance of the temperature at 24°C±1°C and light exposure from 0800 to 2000. Five min following the subcutaneous injection of either 2 mg/kg or 10 mg/kg of Isoxsuprine, the mice were subjected to basal anesthesia for 60 sec using a 5 g cotton ball dampened with 10 ml of ether in a simple covered glass jar. The duration of anesthesia in these mice was 2 to 3 times longer than those in the control groups, which were subcutaneously administered physiological saline solution or 0.1 mg/kg of atropine. Also following basal anesthesia, the mice were inhalated of 0.1 ml ether by a mask method. This produced a significant prolongation on the duration of anesthesia compared with control groups as the case of basal anesthesia. We also investigated the effect of isoxsuprine on the duration of anesthesia and the mortality rate of mice that were exposed to decreasing ether concentrations which were injected into a simple glass jar to achieve basal anesthesia. A 10 mg/kg isoxsuprine injection followed by basal anesthesia with 5 ml ether was proved to be as effective on both the duration of anesthesia and the mortality rate as in the intraperitoneal injection of 50 mg/kg pentobarbital sodium following the subcutaneous injection of 10 mg/kg isoxsuprine, the duration of anesthesia was approximately twice (mean 79 min. 35 sec.) longer than that of the control group. By the results obtained from this experiment, it was apparent that isoxsuprine significantly increased the duration of anesthesia in combination with ether or pentobarbital.
