K+ concentrations were measured with K+ sensitive liquid ion exchanger microelectrodes in situ and in vitro in the mucus layer at the luminal cell surface of the proximal and the distal colon in guinea pig.
In a first series of experiments K+ concentrations were increased in the luminal solution from 0 to 70 mmol·l−1; the serosal K+ concentrations were kept in vitro at 5.4 mmol·l−1. In the proximal colon mean K+ concentration in the microclimate was in vitro 7.9±3.5 mmol·l−1, and independent from mucosal concentrations. In the distal colon in vitro, and in situ in the proximal as well as in the distal colon, K+ concentrations in the microclimate were increased slightly when K+ concentrations were elevated in the luminal solution up to 70 mmol·l−1.
In a second series of in vitro studies K+ concentrations were also altered in the serosal fluid. In the proximal and in the distal colon K+ concentrations increased linearily with elevated K+ concentrations in the serosal solutions.
A temporarily interrupted mucosal blood flow resulted in a significant increase in the K+ concentration in the microclimate.
A paracellular shunt pathway and a high preepithelial diffusion barrier for K+ would explain the observed K+ concentrations in the microclimate at the luminal cell surface.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Bowen JC, Garg DK (1977) Effect of graded mechanical ischemia on oxygen tension and electrical potential in the canine gastric mucosa. Gastroenterol 72:84–88
Clauss W, Dürr J, Rechkemmer G (1985a) Characterisation of conductive pathways in guinea pig distal colon in vitro. Am J Physiol 248:G176-G183
Clauss W, Schäfer H, Horch I, Hörnicke H (1985b) Segmental differences in electrical properties and Na+ transport of rabbit caecum, proximal and distal colon in vitro. Pflügers Arch 403:278–282
Dagostino M, Lee CO (1982) Neutral carrier Na+ and Ca2+ selective microelectrodes for intracellular application. Biophys J 40:199–207
Duffey ME (1984) Intracellular pH and bicarbonate activities in rabbit colon. Am J Physiol 246:C558-C561
Edmonds CJ, Smith T (1979) Epithelial transport pathways of rat colon determined in vivo by impulse response analysis. J Physiol 269:471–485
Forster ES, Hayslett JP, Binder HJ (1984) Colonic potassium transport. In: Donowitz M, Sharp CWG (eds) Mechanisms of intestinal electrolyte transport and regulation by calcium. Liss, New York
Frizzell RA, Koch MJ, Schultz SG (1976) Ion transport by rabbit colon. I Active and passive components. J Membrane Biol 27:297–316
Fromm M, Schultz SG (1981) K+ transport across rabbit descending colon in vitro: evidence for single file diffusion through paracellular pathway. J Membr Biol 63:93–98
Lucas ML, Cannon MJ (1983) Measurement of sodium ion concentration in the unstirred layer of rat small intestine by polymer Na+ sensitive electrodes. Biochim et Biophys Acta 730:41–48
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
Luciano L, Reale E, Rechkemmer G, Engelhardt Wv (1984) Structure of zonulae occludentes and the permeability of the epithelium to short-chain fatty acids in the proximal and the distal colon of guinea pig. J Membrane Biol 82:145–156
McCabe RD, Smith PL (1985) Colonic potassium and chloride secretion: Role of a cAMP and calcium. Am J Physiol 248:G103-G109
McNeil NI, Ling KLE (1984) Large intestinal mucosal surface pH in rat and man. In: Skadhauge E, Heintze W (eds) Intestinal absorption and secretion. MTP Press, Lancaster, UK, pp 103–109
Menguy R, Desbaillets L, Masters YF (1974) Mechanisms of stress ulcer: influence of hypovolemic shock on energy metabolism in the gastric mucosa. Gastroenterol 66:46–55
Moody GJ, Thomas JDR (1971) Selective ion-sensitive electrodes. Merrow, Watword, Hertfordshire, UK, pp 275–302
Nellans HN, Frizzell RA, Schultz SG (1974) Brush-border processes and transepithelial Na and Cl transport by rabbit ileums. Am J Physiol 226:1131–1141
Rechkemmer G, Wahl M, Kuschinski H, Engelhardt Wv (1986) pH microclimate at the luminal surface of the intestinal mucosa of guinea pig and rat. Pflügers Arch 407:33–40
Robinson RA, Stokes RH (1970) Electrolyte solutions. Butterworths, London, p 479
Robinson JWL, Haroud M, Winistörfer B, Miskovitch V (1974) Recovery of function and structure of dog ileum and colon following two hour's acute ischaemia. Europ J Clin Invest 4:443–452
Sakata T, Engelhardt Wv (1981) Luminal mucin in the large intestine of mice, rats and guinea pigs. Cell Tissue Res 219:629–635
Shephard KL (1982) The influence of mucus on the diffusion of ions across the oesaphagus of fish. Physiol Zool 55:23–34
Shephard KL (1984) Diffusion of chloride ions into the mucus on the oesophagus of Enophrys bison, a marine teleost fish. Pflügers Arch 402:207–210
Shiau YF, Fernandez P, Jackson MJ, McMonagle S (1985) Mechanisms maintaining a low pH microclimate in the intestine. Am J Physiol 248:G608-G617
Williams SE, Turnberg LA (1980) Retardation of acid diffusion by pig gastric mucus. A potential role in mucosal protection. Gastroenterology 79:299–304
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
Wills NK (1985) Apical membrane potassium and chloride permeabilities in surface cells of rabbit descending colon epithelium. J Physiol 358:433–445
About this article
Cite this article
Engelhardt, W.v., Kück, U. & Krause, M. Potassium microclimate at the mucosal surface of the proximal and the distal colon of guinea pig. Pflugers Arch. 407, 625–631 (1986). https://doi.org/10.1007/BF00582643
- Guinea pig
- Mucus layer
- Preepithelial barrier