Activation of basolateral Cl− channels in the rat colonic epithelium during regulatory volume decrease
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Abstract
Exposure to a hypotonic medium caused an increase in the diameter of isolated crypts from the rat colon. The increase in cell volume was only transient and lasted about 7 min. Despite of the continuous presence of the hypotonic medium, cell volume decreased again. This regulatory volume decrease (RVD) was inhibited by 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB), a Cl− channel blocker, and by Ba2+, a K+ channel blocker. Cell-attached patch-clamp recordings revealed that the RVD was associated with the activation of previously silent basolateral channels. These channels were identified after excision of the patch as Cl− channels (28 pS) and as K+ channels (45–60 pS). The RVD was dependent on the presence of external Ca2+. The phospholipase A2 inhibitor, quinacrine, and the lipoxygenase blocker, nordihydroguaiaretic acid, inhibited RVD, while indomethacin had no effect. In Ussing chamber experiments an exposure to hypotonic media caused an initial, transient increase in tissue conductance (Gt), followed by a prolonged decrease in short-circuit current (Isc) and the potential difference (V). The height of the electrical response was dependent on the decrease in the osmolarity in a range from 20 mosmol l−1 to 90 mosmol l−1. The increase in Gt was blocked by NPPB and Ba2+, whereas the decrease in Isc or V was inhibited by NPPB but enhanced by Ba2+. This suggests that in the later phase the osmotically induced Cl− conductance exceeds the K+ conductance leading to an electrogenic response, while the initial response of the RVD is an opening of Cl− and K+ channels in a ratio of about 1∶1. With respect to the inhibitory efficacy of nordihydroguaiaretic acid and the inefficacy of indomethacin, leukotrienes seem to be involved in the mediation of this response.
Key words
Osmoregulation Cl− channel K+ channel Leukotrienes Calcium Rat colonPreview
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References
- 1.Bear C (1990) A nonselective cation channel in rat liver cells is activated by membrane stretch. Am J Physiol 258:C421-C428Google Scholar
- 2.Böhme M, Diener M, Rummel W (1991) Calcium- and cyclic-AMP-mediated secretory responses in isolated colonic crypts. Pflügers Arch 419:144–151Google Scholar
- 3.Cala PM (1980) Volume regulation of Amphiuma red blood cells. The membrane potential and its implications regarding the nature of the ion-flux pathway. J Gen Physiol 76:683–708Google Scholar
- 4.Chang J, Musser JH, McGregor H (1987) Phospholipase A2: function and pharmacological regulation. Biochem Pharmacol 36:2429–2436Google Scholar
- 5.Diener M, Rummel W (1989) Actions of the chloride channel blocker NPPB on absorptive and secretory transport processes in rat colon. Acta Physiol Scand 137:215–222Google Scholar
- 6.Diener M, Eglème C, Rummel W (1991) Phospholipase C-induced anion secretion and its interaction with carbachol in the rat colonic mucosa. Eur J Pharmacol 200:267–276Google Scholar
- 7.Diener M, Rummel W, Mestres P, Lindemann B (1989) Single chloride channels in colon mucosa and isolated colonic enterocytes of the rat. J Membr Biol 108:21–30Google Scholar
- 8.Fisher RS, Spring KR (1984) Intracellular activities during volume regulation by Necturus gall bladder. J Membr Biol 78:187–199Google Scholar
- 9.Frizzell RA, Halm DR, Rechkemmer G, Shoemaker RL (1986) Chloride channel regulation in secretory epithelia. Fed Proc 45:2727–2731Google Scholar
- 10.Giraldez F, Valverda MA, Sepúlveda FV (1988) Hypotonicity increases apical membrane Cl− conductance in enterocytes. Biochim Biophys Acta 942:353–356Google Scholar
- 11.Grinstein S, Clarke CA, Dupre A, Rothstein A (1982) Volume-induced increase of anion permeability in human lymphocytes. J Gen Physiol 80:807–823Google Scholar
- 12.Hazama A, Okada Y (1988) Ca2+-sensitivity of volume-regulatory K+ and Cl− channels in cultured human epithelial cells. J Physiol (Lond) 402:687–702Google Scholar
- 13.Hoffmann EK, Kolb HA (1991) Mechanism of activation of regulatory volume responses after cell swelling. In: Gilles R, Hoffmann EK, Bolis L (eds) Comparative and environmental physiology, vol 9. Volume and osmolality control in animal cells. Springer, Berlin Heidelberg New York, pp 140–185Google Scholar
- 14.Hoffmann EK, Simonsen LO, Lambert IH (1984) Volume-induced increase of K+ and Cl− permeabilities in Ehrlich ascites tumor cells. Role of internal Ca2+. J Membr Biol 78:211–222Google Scholar
- 15.Hudson L, Schultz SG (1988) Sodium-coupled glycine uptake by Ehrlich ascites tumor cells results in an increase in cell volume and plasma membrane channel activity. Proc Natl Acad Sci USA 85:279–288Google Scholar
- 16.Lambert IH, Hoffman EK, Christensen P (1987) Role of prostaglandins and leukotrienes in volume regulation by Ehrlich ascites tumor cells. J Membr Biol 98:247–256Google Scholar
- 17.Larsen M, Spring KR (1987) Volume regulation in epithelia. Curr Top Membr Transp 30:105–123Google Scholar
- 18.Lau KR, Hudson R, Schultz SG (1984) Cell swelling increases a barium-inhibitable potassium conductance in the basolateral membrane of Necturus small intestine. Proc Natl Acad Sci USA 81:3591–3594Google Scholar
- 19.Lau KR, Hudson RL, Schultz SG (1986) Effect of hypertonicity on the increase in basolateral conductance in Necturus small intestine in response to Na+-sugar cotransport. Biochim Biophys Acta 855:193–196Google Scholar
- 20.Macknight ADC (1991) Volume regulation in epithelia. In: Gilles R, Hoffmann EK, Bolis L (eds) Comparative and environmental physiology, vol 9. Volume and osmolality control in animal cells. Springer, Berlin Heidelberg New York, pp 3–42Google Scholar
- 21.Macleod RJ, Hamilton JR (1991) Separate K+ and Cl− transport pathways are activated for regulatory volume decrease in jejunal villus cells. Am J Physiol 260:G405-G415Google Scholar
- 22.MacRobbie EAC, Ussing HH (1961) Osmotic behaviour of the epithelial cells of frog skin. Acta Physiol Scand 53:348–365Google Scholar
- 23.Malagodi MH, Chiou CY (1974) Pharmacological evaluation of a new Ca2+ antagonist, 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8): studies in smooth muscles. Eur J Pharmacol 27:25–33Google Scholar
- 24.Morris AP, Kirk KL, Frizzell RA (1990) Simultaneous analysis of cell Ca2+ and Ca2+-stimulated chloride conductance in colonic epithelial cells (HT29). Cell Regul 1:951–963Google Scholar
- 25.O'Brien JA, Walters RJ, Sepúlveda FV (1991) Regulatory volume decrease in small intestinal crypts is inhibited by K+ and Cl− channel blockers. Biochim Biophys Acta 1070:501–504Google Scholar
- 26.Robinson JWL (1970) The difference in sensitivity to cardiac steroids of (Na++K+)-stimulated ATPase and amino acid transport in the intestinal mucosa of the rat and other species. J Physiol (Lond) 206:41–60Google Scholar
- 27.Rothstein A, Bear C (1989) Cell volume changes and the activity of the chloride conductive path. Ann New York Acad Sci 574:294–308Google Scholar
- 28.Sharon P, Stenson WF (1985) Metabolism of arachidonic acid in acetic acid colitis in rats. Similarity to human inflammatory bowel disease. Gastroenterology 88:55–63Google Scholar
- 29.Shen TY (1979) Prostaglandin synthetase inhibitors: I. In: Vane JR, Ferreira SH (eds) Antiinflammatory drugs. Handbook of experimental pharmacology, vol 50/II. Springer, Berlin Heidelberg, pp 305–347Google Scholar
- 30.Sheppard DN, Giraldez F, Sepúlveda FV (1988) K+ channels activated by L-alanine in isolated Necturus enterocytes. FEBS Lett 234:446–448Google Scholar
- 31.Sheppard DN, Giraldez F, Sepúlveda FV (1988) Kinetics of voltage- and Ca2+-activation and Ba2+ blockade of a largeconductance K+ channel from Necturus small intestine. J Membr Biol 105:65–75Google Scholar
- 32.Ussing HH (1982) Volume regulation of frog skin epithelium. Acta Physiol Scand 114:363–369Google Scholar
- 33.Ussing HH (1985) Volume regulation and basolateral co-transport of sodium, potassium, and chloride ions in frog skin epithelium. Pflügers Arch 405 [Suppl 1]:S2-S7Google Scholar
- 34.Wangemann P, Wittner M, Di Stefano A, Englert HC, Lang HJ, Schlatter E, Greger R (1986) Cl−-channel blockers in the thick ascending limb of the loop of Henle. Structure activity relationship. Pflügers Arch 407:S128-S141Google Scholar
- 35.Worrell RT, Butt AG, Cliff WH, Frizzell RA (1989) A volume-sensitive chloride conductance in human colonic cell line T84. Am J Physiol 256:C1111-C1119Google Scholar