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The potential and short‐circuit current across isolated rumen epithelium of the sheep
Author(s) -
Ferreira H. G.,
Harrison F. A.,
Keynes R. D.
Publication year - 1966
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1966.sp008114
Subject(s) - epithelium , propionate , rumen , chemistry , bicarbonate , transepithelial potential difference , butyrate , biophysics , biology , biochemistry , ion transporter , membrane , genetics , organic chemistry , fermentation
1. A technique is described for working with isolated sheets of rumen epithelium. Epithelium was obtained at operations for rumen fistulation or in acute experiments and was rapidly mounted between two cone‐shaped chambers each of which held 40 ml. of bathing fluid. The fluids were gassed with 95% O 2 /5% CO 2 and 20 cm 2 of epithelium was exposed to the fluids. 2. Electrical measurements were made of ( a ) the potential generated across the epithelium, ( b ) the short‐circuit current which flowed and ( c ) the resistance of the epithelium. 3. The results are grouped according to the composition of the sheep Ringer solution used to bathe the epithelium. The most stable preparation was obtained when the solutions contained 5 m M each of glucose, acetate, propionate and butyrate as well as bicarbonate and phosphate buffers. 4. In Cl − media, the average initial p.d., short‐circuit current (s.‐c.c.) and resistance were 9·3 mV, 11·6 μA/cm 2 and 1156 Ω. cm 2 respectively. Higher values of 17·6 mV, 17·3 μA/cm 2 and 1501 Ω. cm 2 were recorded in SO 4 2- media. In both media, the s.‐c.c. declined at approximately 1·5 μA/cm 2 .hr and preparations were suitable for study over periods from 4 to 6 hr. 5. When the concentration of potassium was varied on either side of the epithelium at constant [Na + ], the potential showed a linear relation with log [K + ] for both sides of the epithelium. 6. Changing the sodium concentrations at constant [K + ] on either side of the epithelium caused negligible alterations in the potential. 7. Exclusion of sodium from the media bathing both sides of the epithelium abolished the potential and s.‐c.c. 8. The addition of ouabain to the blood side of the preparation abolished the potential and s.‐c.c. whereas on the rumen side these parameters were unaffected.