Abstract
The authors investigated the effect of the calcium channel antagonist diltiazem on gut absorptive capacity after hemorrhage in rats. Carotid and femoral arterial catheters, portal and jugular venous catheters, and nasogastric tubes were placed in 12 anesthetized animals. After recovery from the anesthetic, eight animals (groups 2 and 3) were bled via the femoral catheter to a mean arterial pressure (MAP) of 40 mm Hg. This level of hypotension was maintained by continued bleeding to the maximal bleedout volume (approximately 60% of the animal's circulating blood volume), followed by infusion of lactated Ringer's solution until 40% of the maximal bleedout volume had been returned. The animals were then resuscitated with lactated Ringer's solution. Four rats (group 1) were not hemorrhaged and served as sham controls. During resuscitation the animals in group 2 received an additional 1 mL of saline, whereas those in group 3 were treated with diltiazem 400 μg/kg body weight in 1 mL of saline. MAP was measured throughout the experiment. Portal and central venous pressures were measured at the onset of hemorrhage, maximal bleedout, end of hemorrhage, end of resuscitation, and just before the D-xylose absorption tests. Gut absorptive, capacity was determined using the 1-hour D-xylose absorption test at 2 hours and 4 hours after the end of hemorrhage. The D-xylose was administered via the nasogastric tubes; portal blood was sampled 1 hour later and assayed for D-xylose.
The animals treated with diltiazem had a significantly lower MAP 2 hours after the end of hemorrhage, whereas at 4 hours, both hemorrhaged groups were significantly lower than controls. Central venous and portal pressures were significantly lower in the hemorrhaged groups at maximal bleedout and end of hemorrhage compared with the sham-operated animals. However, these values returned to normal by 2 hours after the end of hemorrhage. There were no differences in the venous pressures between the animals receiving saline or diltiazem. The saline-treated animals' gut absorptive capacity as measured by D-xylose absorption was significantly reduced at 2 and 4 hours after the end of hemorrhage. Diltiazem administration restored gut absorptive capacity to normal at both time points after the end of hemorrhage.
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