Carbonic anhydrase influences asymmetric sodium and acetate transport across omasum of sheep
5
조회
0
다운로드
0
인용
0
참고문헌
키워드
초록
Objective: Omasum is an important site for the absorption of short chain fatty acids. The major route for the transport of acetate is via sodium hydrogen exchanger (NHE). However, a discrepancy in the symmetry of sodium and acetate transport has been previously reported, the mechanism of which is unclear. In this study, we investigated the possible role of carbonic anhydrase (CA) for this asymmetry.Methods: Omasal tissues were isolated from healthy sheep (N = 3) and divided into four groups; pH 7.4 and 6.4 alone and in combination with Ethoxzolamide. Electrophysiological measurements were made using Ussing chamber and the electrical measurements were made using computer controlled voltage clamp apparatus. Effect(s) of CA inhibitor on acetate and sodium transport flux rate of Na<sup>22</sup> and <sup>14</sup>C-acetate was measured in three different flux time periods. Data were presented as mean±standard deviation and level of significance was ascertained at p≤0.05.Results: Mucosal to serosal flux of Na (J<sub>ms</sub>Na) was greater than mucosal to serosal flux of acetate (J<sub>ms</sub>Ac) when the pH was decreased from 7.4 to 6.4. However, the addition of CA inhibitor almost completely abolished this discrepancy (J<sub>ms</sub>Na ≈ J<sub>ms</sub>Ac).Conclusion: The results of the present study suggest that the additional protons required to drive the NHE were provided by the CA enzyme in the isolated omasal epithelium. The findings of this study also suggest that the functions of CA may be exploited for better absorption in omasum.
Abstract
Objective: Omasum is an important site for the absorption of short chain fatty acids. The major route for the transport of acetate is via sodium hydrogen exchanger (NHE). However, a discrepancy in the symmetry of sodium and acetate transport has been previously reported, the mechanism of which is unclear. In this study, we investigated the possible role of carbonic anhydrase (CA) for this asymmetry. Methods: Omasal tissues were isolated from healthy sheep (N = 3) and divided into four groups; pH 7.4 and 6.4 alone and in combination with Ethoxzolamide. Electrophysiological measurements were made using Ussing chamber and the electrical measurements were made using computer controlled voltage clamp apparatus. Effect(s) of CA inhibitor on acetate and sodium transport flux rate of Na22 and 14C-acetate was measured in three different flux time periods. Data were presented as mean±standard deviation and level of significance was ascertained at p≤0.05. Results: Mucosal to serosal flux of Na (JmsNa) was greater than mucosal to serosal flux of acetate (JmsAc) when the pH was decreased from 7.4 to 6.4. However, the addition of CA inhibitor almost completely abolished this discrepancy (JmsNa ≈ JmsAc). Conclusion: The results of the present study suggest that the additional protons required to drive the NHE were provided by the CA enzyme in the isolated omasal epithelium. The findings of this study also suggest that the functions of CA may be exploited for better absorption in omasum.
참고문헌 (27)
- von Engelhardt W, "Functions of the omasum in small domestic ruminants. IV. Absorption and secretion of electrolytes", Zentralbl Veterinarmed A, 22, pp.367~375 (1975)[DOI]
- Kramer T, "Absorption of short-chain fatty acids across ruminal epithelium of sheep", J Comp Physiol B, 166, pp.262~269 (1996)[DOI]
- Ritzhaupt A, "Identification and characterization of a monocarboxylate transporter(MCT1)in pig and human colon : its potential to transport L-lactate as well as butyrate", J Physiol, 513, pp.719~732 (1998)[DOI]
- Gäbel G, "Transfer of energy substrates across the ruminal epithelium : implications and limitations", Anim Health Res Rev, 3, pp.15~30 (2002)[DOI]
- Tyagi S, "Mechanism of n-butyrate uptake in the human proximal colonic basolateral membranes", Am J Physiol Gastrointest Liver Physiol, 282, pp.G676~82 (2002)[DOI]
- von Engelhardt W, "Effects of amiloride and ouabain on short-chain fatty acid transport in guinea-pig large intestine", J Physiol, 460, pp.455~466 (1993)[DOI]
- von Engelhardt W, "Unidirectional fluxes of short-chain fatty acids across segments of the large intestine in pig, sheep and pony compared with guinea pig", J Comp Physiol B, 165, pp.29~36 (1995)[DOI]
- Smith RH, "Microbial activity in the omasum", Proc Nutr Soc, 43, pp.63~68 (1984)[DOI]
- Tamminga S, "Formation and utilization of end products of lignocellulose degradation in ruminants", Anim Feed Sci Technol, 21, pp.141~159 (1988)[DOI]
- Ali O, "Transport of acetate and sodium in sheep omasum : mutual, but asymmetric interactions", J Comp Physiol B, 176, pp.477~487 (2006)[DOI]
- Boron WF, "Medical physiology: a cellular and molecular approaoch", pp.2017, Saunders
- Klisic J, "Insulin activates Na+", H+exchanger 3 : biphasic response and glucocorticoid dependence, 2002, pp.283, F532~F539
- Andrew G. Spencer, "Intestinal Inhibition of the Na +", H + Exchanger 3 Prevents Cardiorenal Damage in Rats and Inhibits Na + Uptake in Humans, 2014, pp.6(227), ~[DOI]
- Badger MR, "The role of carbonic anhydrase in photosynthesis", Annu Rev Plant Physiol Plant Mol Biol, 45, pp.369~392 (1994)[DOI]
- Martens H, "No evidence for active peptide transport in forestomach epithelia of sheep", J Anim Physiol Anim Nutr, 85, pp.314~324 (2001)[DOI]
- Rabbani I, "Evidence for NHE3-mediated Na transport in sheep and bovine forestomach", Am J Physiol Regul Integr Comp Physiol, 301, pp.R313~R319 (2011)[DOI]
- Martens H, "Transport of Na and Cl across the epithelium of ruminant forestomachs : rumen and omasum. A review", Comp Biochem Physiol A Physiol, 90, pp.569~575 (1998)[DOI]
- Çaushi D, "Transport of HCO3in sheep omasum", pp.2015
- Gäbel G, "SCFA transport in the forestomach of ruminants", Comp Biochem Physiol A Physiol, 118, pp.36774~ (1997)[DOI]
- Allen MS, "Relationship between fermentation acid production in the rumen and the requirement for physically effective fiber", J Dairy Sci, 80, pp.1447~1462 (1997)[DOI]
- Charney AN, "Nonionic diffusion of shortchain fatty acids across rat colon", Am J Physiol Gastrointest Liver Physiol, 274, pp.G518~24 (1998)[DOI]
- Argenzio RA, "Inter-relationship of sodium, chloride, bicarbonate and acetate transport by the colon of the pig", J Physiol, 295, pp.365~381 (1979)[DOI]
- Gäbel P, "Influences of diet, short-chain fatty acids, lactate and chloride on bicarbonate movement across the reticulo-rumen wall of sheep", J Vet Med A, 38, pp.523~529 (1991)[DOI]
- Müller F, "Role of Na+", H+exchange and HCO3transport in pHi recovery from intracellular acid load in cultured epithelial cells of sheep rumen, 2000, pp.170, 337~343
- Butzner JD, "Inhibition of short-chain fatty acid absorption and Na+absorption during acute colitis in the rabbit", Gastroenterology, 106, pp.1190~1198 (1994)[DOI]
- Binder HJ, "Characterization of butyrate-dependent electroneutral Na-Cl absorption in the rat distal colon", Pflugers Arch, 417, pp.365~369 (1990)[DOI]
- Petersen KU, "Stimulation of gallbladder fluid and electrolyte absorption by butyrate", J Membr Biol, 62, pp.183~193 (1981)[DOI]