There are only limited data on sevoflurane minimum alveolar concentration (MAC) in rats. This study was designed to determine the minimum alveolar concentration value for sevoflurane in younger and older rats. Minimum alveolar concentration determination was performed in spontaneously breathing animals, 9-week-old rats (younger, n = 8) and more than 13-month-old rats (older, n = 8). Rats were instrumented with a silastic catheter in the abdominal aorta via the femoral artery to allow for arterial blood gas sampling. Subsequently, minimum alveolar concentration for sevoflurane was determined in 40 younger and 38 older rats. Minimum alveolar concentration for sevoflurane in younger rats was significantly higher than in the older rats (2.68 +/- 0.19 vs. 2.29 +/- 0.19, P < 0.001). Subgroup analysis indicated that minimum alveolar concentration for sevoflurane was not affected by the presence of an arterial catheter in the abdominal aorta (younger, 2.75 +/- 0.08 vs. 2.67 +/- 0.21; older, 2.23 +/- 0.19 vs. 2.30 +/- 0.18). Minimum alveolar concentration is profoundly affected by the age of the animal, but not by limited instrumentation.

There are only limited data on sevoflurane minimum alveolar concentration (MAC) in rats. This study was designed to determine the minimum alveolar concentration value for sevoflurane in younger and older rats. Minimum alveolar concentration determination was performed in spontaneously breathing animals, 9‐week‐old rats (younger, n=8) and more than 13‐month‐old rats (older, n=8). Rats were instrumented with a silastic catheter in the abdominal aorta via the femoral artery to allow for arterial blood gas sampling. Subsequently, minimum alveolar concentration for sevoflurane was determined in 40 younger and 38 older rats. Minimum alveolar concentration for sevoflurane in younger rats was significantly higher than in the older rats (2.68±0.19 vs. 2.29±0.19, P<0.001). Subgroup analysis indicated that minimum alveolar concentration for sevoflurane was not affected by the presence of an arterial catheter in the abdominal aorta (younger, 2.75±0.08 vs. 2.67±0.21; older, 2.23±0.19 vs. 2.30±0.18). Minimum alveolar concentration is profoundly affected by the age of the animal, but not by limited instrumentation.

Nicorandil improved post-ischaemic cardiac function and preserved high-energy phosphates. However, these beneficial effects of nicorandil were abolished by the combination with isoflurane or sevoflurane. In addition, sevoflurane increased hydroxyl radical formation in the post-ischaemic reperfused heart.

Amrinone, a phosphodiesterase inhibitor, is a non-glycosidic noncatecholamine with both vasodilator and positive inotropic effects. We were interested in assessing the effect of amrinone on postischemic cardiac performance in the isolated heart-lung preparation. Twenty-four male Wistar-ST rats were used. They were randomly divided into three groups. Amrinone, 10 μg·ml or 100 μg·ml was administered 8 min after the start of perfusion except in the control group. Ten minutes after the start of perfusion, all hearts were made globally ischemic for 8 min. Subsequently, the preparations were reperfused for 10 min. At the end of the experimental period, the hearts were freeze-clamped, and then myocardial high-energy phosphates, lactate, pyruvate, and glycogen were measured. Hemodynamic parameters in all groups decreased significantly during ischemia. However, there were no significant differences among the groups. The myocardial ATP level in the 100 μg·ml group was significantly higher than that in the control group. Adenosine diphosphate (ADP) and adenosine monophosphate (AMP) levels in the 100 μg·ml group were significantly lower than those in the control group. Myocardial lactate, pyruvate, and glycogen levels were not significantly different among the groups. This result suggests that amrinone improves postischemic myocardial metabolism. Although we could not measure coronary flow, amrinone might increase coronary flow with direct coronary vasodilation which would have increased the myocardial ATP and energy charge levels.

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