Abstract
Segments of guinea pig jejunum, proximal and distal colon and of rat jejunum were superfused either in vivo or in vitro with different electrolyte solutions. The pH in the bulk phase solution and at the surface of the epithelium was measured with two different types of glass pH-microelectrodes, a pointed tip (Hinke-type) and a flat membrane electrode (Dubuisson-type); both types of electrodes gave the same results.
The existence of a pH-microclimate at the surface of the mucosa was demonstrated under both in vivo and in vitro conditions. In vivo the pH-microclimate was stable and virtually independent of changes in the luminal bulk phase pH. When the bulk phase pH of the guinea pig colon was changed between pH 5 and pH 8.6, the mean pH in the microclimate was 7.08±0.15 (n=163) in the proximal colon and 6.91±0.14 (n=75) in the distal colon. In the guinea pig jejunum pH in the microclimate was 7.37±0.21 (n=10) while the luminal pH was 7.27±0.10.
Under in vitro conditions, the pH in the microclimate was more acidic (guinea pig jejunum ΔpH 0.93, rat jejunum ΔpH 0.40, guinea pig proximal colon ΔpH 0.22).
Addition of glucose (10 mM) or short-chain fatty acids (80–90 mM) to the luminal solution or replacement of sodium by lithium did not influence the pH in the microclimate significantly. Also the addition of acetazolamide, amiloride, SITS or sodium deoxycholate to the luminal solution, did not affect the pH in the microclimate in vivo. A temporary interruption of the blood supply caused acidification of the pH in the microclimate. Restoring the blood flow reversed the effect, and the pH returned to the original values within a few minutes.
The originally proposed acid-microclimate could not be confirmed under in vivo experimental conditions either in the jejunum or in the colon by direct measurement with pH-sensitive glass-microelectrodes.
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References
Allen A, Garner A (1980) Mucus and bicarbonate secretion in the stomach and their possible role in mucosal protection. Gut 21:249–262
Bahari HMM, Ross IN, Turnberg LA (1982) Demonstration of a pH gradient across the mucus layer on the surface of human gastric mucosa in vitro. Gut 23:513–516
Bickel M, Kauffman GL Jr (1981) Gastric mucus gel thickness: effect of distension, 16,16-dimethyl prostaglandin E2 and carbenoxolone. Gastroenterology 80:770–775
Daniel H, Neugebauer B, Kratz A, Rehner G (1985) Localization of acid microclimate along intestinal villi of rat jejunum. Am J Physiol 248:G293-G298
Engelhardt W v, Rechkemmer G (1983a) The physiological effects of short-chain fatty acids in the hind gut. In: Wallace E, Bell L (eds) Fibre in human and animal nutrition. Royal Soc New Zealand Bull 20:149–155
Engelhardt W v, Rechkemmer G (1983b) Absorption of inorganic ions and short-chain fatty acids in the colon of mammals. In: Gilles-Baillien M, Gilles R (es) Intestinal transport. Fundamental and comparative aspects. Springer, Berlin Heidelberg New York Tokyo, pp 26–45
Engelhardt W v, Rechkemmer G (1984) Colonic transport of shortchain fatty acids and the importance of the microclimate. In: Skadhauge E, Heintze K (eds) Intestinal absorption and secretion. MTP Press, Lancaster, pp 93–101
Flemström G, Kivilaakso E (1983) Demonstration of a pH gradient at the luminal surface of rat duodenum in vivo and its dependence on mucosal alkaline secretion. Gastroenterol 84:787–794
Högerle ML, Winne D (1983) Drug absorption by the rat jejunum perfused in situ. Dissociation from the pH-partition theory and role of microclimate-pH and unstirred layer. Naunyn-Schmiedeberg's Arch Pharmacol 322:249–255
Hogben C, Tocco D, Brodie BB, Schanker L (1959) On the mechanism of intestinal absorption of drugs. J Pharmacol Exp Therap 125:275–282
Jackson MJ, Meaney CA (1984) Intestinal weak electrolyte transport-models and mechanisms. In: Skadhauge E, Heintze K (eds) Intestinal absorption and secretion. MTP Press Ltd, Lancaster, pp 83–91
Jackson MJ, Shiau Y-F, Bane S, Fox M (1974) Intestinal transport of weak electrolytes. Evidence in favour of a three compartment system. J Gen Physiol 63:187–213
Jackson MJ, Williamson AM, Dombrowski WA, Garner DE (1978) Intestinal transport of weak electrolytes. Determinants of influx at the luminal surface. J Gen Physiol 71:301–327
Kauffman GL Jr, Reeve JJ, Grossman MI (1980) Gastric bicarbonate secretion, effect of topical and intravenous 16,16-dimethyl prostaglandin E2. Am J Physiol 239:G44-G48
Kerss S, Allen A, Garner A (1982) A simple method for measuring thickness of the mucus layer adherent to rat, frog and human gastric mucosa: influence of feeding, prostaglandin, N-acetylcysteine and other agents. Clin Sci 63:187–195
Lucas ML (1976) The association between acidification and electrogenic events in the rat proximal jejunum. J Physiol 257:645–662
Lucas ML (1983) Determination of acid surface pH in vivo in rat proximal jejunum. Gut 24:734–739
Lucas ML (1984) Weak-electrolyte absorption and the acid microclimate. In: Skadhauge E, Heintze K (eds) Intestinal absorption and secretion. MTP Press Ltd, Lancaster, pp 39–54
Lucas ML, Blair JA (1978) The magnitude and distribution of the acid microclimate in proximal jejunum and its relation to luminal acidification. Proc R Soc Lond A 200:27–41
Lucas ML, Schneider W, Haberich FJ, Blair JA (1975) Direct measurement by pH-microelectrode of the pH microclimate in rat proximal jejunum. Proc R Soc Lond B 192:39–48
Lucas ML, Blair JA, Cooper BT, Cooke WT (1976) Relationship of the acid micro-climate in rat and human intestine to malabsorption. Biochem Soc Trans 4:154–156
Lucas ML, Cooper MT, Lei FH, Johnson IT, Holmes GKT, Blair JA, Cooke WT (1978) Acid microclimate in coeliac and Crohn's disease: a model for folate malabsorption. Gut 19: 735–742
Lucas ML, Lei FH, Blair JA (1980) The influence of buffer pH, glucose and sodium ion concentration on the acid microclimate in rat proximal jejunum in vitro. Pflügers Arch 385: 137–142
McNeil NI, Ling KLE (1984) Large intestinal mucosal surface pH in rat and man. In: Skadhauge E, Heintze K (eds) Intestinal absorption and secretion. MTP Press Ltd, Lancaster, pp 103–109
Rechkemmer G, Engelhardt W v (1981) Eine kombinierte Injektions-und Inhalationsnarkose beim Meerschweinchen. DTW 88:394–397
Rechkemmer G, Wahl M, Kuschinsky W, Engelhardt W v (1979) pH-microlimate at the surface of the intestine in guinea pig and rat. Pflügers Arch 382:R31
Robert A, Böttcher W, Golanska E, Kauffman GL Jr (1984) Lack of correlation between mucus gel thickness and gastric cytoprotection in rats. Gastroenterol 86:670–674
Roediger WEW (1979) Nutrition of the colonic mucosa. In: Truelove SC, Willoughby CP (eds) Topics in gastroenterology, vol 7. Blackwell Scientific Publications. Oxford London Edinburgh Melbourne, pp 281–287
Ross IN, Bahari HMM, Turnberg LA (1981) The pH gradient across mucus adherent to rat fundic mucosa in vivo and the effect of potential damaging agents. Gastroenterol 81: 713–718
Sakata T, Engelhardt W v (1981) Luminal mucin in the large intestine of mice, rats and guinea pigs. Cell Tiss Res 219: 629–635
Schanker LS (1959) Absorption of drugs from the rat colon. J Pharmacol Exp Ther 126:283–290
Schneider W, Wahl M, Kuschinsky W, Thurau K (1977) The use of microelectrodes for measurement of local H+ activity in the cortical subarachnoidal space of cats. Pflügers Arch 372:103–107
Shiau Y-F, Fernandez P, Jackson MJ, McMonagle S (1985) Mechanisms maintaining a low-pH microclimate in the intestine. Am J Physiol 248:G608-G617
Takeuchi K, Magee D, Critchlow J, Matthews J, Silen W (1983) Studies of the pH gradient and thickness of frog gastric mucus gel. Gastroenterol 84:331–340
Vogel G, Passmann H, Meyering E (1970) Besonderheiten der Sorption im Intestinaltrakt des Meerschweinchens. Pflügers Arch 321:259–273
Watkins DW, Pintauro WL (1979) Luminal alkalinization by the guinea pig cecum in vitro, an electro-neutral process. Experientia 35:356–358
Williams SE, Turnberg LA (1981) Demonstration of a pH gradient across mucus adherent to rabbit gastric mucosa: evidence for a ‘mucus-bicarbonate’ barrier. Gut 22:94–96
Winne D (1977) Shift of pH-absorption curves. J Pharmacokinet Biopharm 5:53–94
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Some preliminary data have been discussed at scientific meetings (Rechkemmer et al. 1979; Engelhardt and Rechkemmer 1983b; Engelhardt and Rechkemmer 1984
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Rechkemmer, G., Wahl, M., Kuschinsky, W. et al. pH-microclimate at the luminal surface of the intestinal mucosa of guinea pig and rat. Pflugers Arch. 407, 33–40 (1986). https://doi.org/10.1007/BF00580717
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DOI: https://doi.org/10.1007/BF00580717