A Comparison of Some of the Permeability Characteristics of Intact and Tape-stripped Hamster Cheek Pouches in vitro

Abstract

Cheek pouches were removed from anesthetized hamsters and were either tape-stripped or left intact and then mounted in Ussing chambers, where they were bathed in Krebs-Ringer bicarbonate saline. A potential difference could be measured across all pouches and was stable for over an hour across the unstripped pouches. The electrical resistance across the unstripped pouches was high (8960 Ω.cm2), whereas the resistance across the tape-stripped pouches was significantly lower (p<0.01), suggesting that these pouches are likely to be more permeable than the unstripped pouches. Reflection coefficients of urea, ethanol, and glycerol were derived by means of streaming potentials. Values for intact pouches were all close to 1 and for tape-stripped pouches were 0.938, 0.822, and 0.509, respectively. Permeability coefficients for urea and ethanol across intact and tape-stripped pouches were, respectively, 12.5 × 10-9 cm/min; 27.6 x 10-9 cm/min; 2325 × 10 -9 cmlmin ; and 28471 × 10-9 cmlmin. The hamster cheek pouch has a high electrical resistance; it is an impermeable structure in which the keratin layer appears to provide a major barrier to the passage of water, ions, and certain solutes.