Influence of Anesthetic Regimens on Intestinal Absorption in Rats

We compared the influence of anesthetic regimens using urethane (U), pentobarbital (P), ether (E), and ketamine/midazolam (K) on the intestinal absorption of several probes using a single-pass perfusion technique in rats. The selected probes were D-glucose (1 mM) for the resistance of the unstirred water layer (UWL), D-glucose (100 mM) for the capacity of carrier-mediated D-glucose transport, L-glucose, and urea for membrane-limited passive transport, and tritiated water (3H2O) for blood flow at the absorption site. The absorbed fraction of D-glucose (1 mM) was the smallest for U and the largest for P, suggesting that the resistance of UWL is the largest for U and the smallest for P. The absorbed fraction of D-glucose (100 mM) was the largest for P (U = E = K < P), suggesting a higher capacity of carrier-mediated D-glucose transport for P. The absorbed fraction of urea was similar for all anesthetics, while that of L-glucose was the smallest for K (U = P = E > K). Although the results for these two markers of membrane-limited passive transport were inconsistent, the passive permeability of the intestinal membrane may be lower when treating with K. The intestinal absorptions of D-glucose (1 and 100 mM), L-glucose, and urea were, in general, lower with any of the anesthetics than under nonanesthesia (N), suggesting increased resistance of UWL and decreased intestinal membrane permeability by carrier-mediated and passive transport under anesthesia. The only exception was the absorption of D-glucose (100 mM) under P, which was comparable to that under N.(ABSTRACT TRUNCATED AT 250 WORDS)