Intercalated cells

AQP6 is expressed in the intercalated cells of the kidney collecting duct. This channel is hardly permeable to water, but capable of transporting anions, including chloride, and is therefore thought to play a role in maintenance of body acid-base balance or in intracellular vesicle acidification. 

Principal and intercalated cells of the collecting ducts. Principal (top) cells reabsorb Na+ and the secreted K+. Na+ entry across apical cell membranes is mediated by a Na+ channel. Na+ exit across basolateral cell membranes is effected by the NaVK+-ATPase, shown by the filled circle in the principal cell. The rates of Na+ reabsorption and K+ secretion are regulated by aldosterone. Intercalated (bottom) cells reabsorb K+ and HCOa and secretes H+. K+ entry and H+secretion are mediated by an H+/K ATPase, which is shown by the filled circle in the apical cell membrane of the intercalated cell. 

The reason(s) observed in our studies for the preferential transduction of the proximal tubule and intercalated cells is not entirely clear. Several possible mechanisms may be implicated. The early steps of AAV infection involve attachment to a variety of cell surface receptors (heparan sulfate proteoglycan, fibroblast growth factor receptor, and av-/ 5 integrin) followed by a clathrin-dependent... 

Brown, D., Weyer, P. and Orci, L. (1987). Nonclathrin-coated vesicles are involved in endocytosis in kidney collecting duct intercalated cells. Anat. Rec. 218, 237-242. 

The principal and intercalated cells of the collecting tubule aie responsible for Na+- K+ exchange and for H+ secretion and K+ reabsorption, respectively. Stimulation of aldosterone receptors in the principal cells results in Na+ reabsorption and K+ secretion. Antidiuretic hormone (ADH, vasopressin) receptors promote the reabsorption of water from the collecting tubules and ducts (Figure 23.3). This action is mediated by cAMP. 

As for the amygdala, Di receptors are highly concentrated in the intercalated cells, with intermediate density of Di receptors in the magnocellular and parvicellular basolateral nucleus, whereas a low density is found in the central nucleus (Scibilia et al., 1992). 

Interleukin-18 (IL-18), a recently described member of the IL-1 cytokine family, is now recognized as an important regulator of innate and acquired immune responses. IL-18 is a mediator of inflammation and ischemic tissue injury in many organs. IL-18 is con-stitutively expressed by intercalated cells of the late distal convoluted tubule, fhe connecting tubule, and the collecting duct of the healthy human kidney [229]. It is expressed at sites of chronic inflammation, in autoimmune diseases, in a variety of cancers, and in the... 

Gauer S, SichlerO, Obermuller N, Floizmann Y, Kiss E, Sobkowiak E, PfeilschifterJ, Geiger H, Muhl H, Hauser lA. IL-18 is expressed in the intercalated cell of human kidney. Kidney Int. 2007 72 1081-7. 

CD-IC collecting duct intercalated cell DICE difference in-gel electrophoresis... 

H generated in the intercalated cells moves into the luiM fluid by way of the H -ATPa-sc "... 

Bceau.se the latter two processes predominate, one may view the activities at site 4 as an exchange of luminal lluiil Na for principal cell K and intercalated cell H. Tlic exchange of luminal fluid Na for intracellular H orK normally is assiK iated with the reabsorption of only 2 to.H of the filtered load of Na. and the distal location of this exchange. sy.stcm dictates the final acidity and K content of the urine. 

CA is located both intracellularly (type II CA) and in the luminal bru.sh border membrane (type IV CA) of proximal convoluted tubule cells (Fig. 18-3A). Both of these site I locations are major targets of the CA inhibitors." This group of diuretics also inhibits intracellular CA in the intercalated cells of the connecting and cortical collecting tubules (i.e.. site 4 Fig. 18-6). 

Auborn, J.J., and Barberio, Y.L. 1987. Lithium intercalation cells without metallic lithium. Molybdenum dioxide/lithium cobalt dioxide and tungsten dioxide/lithium cobalt dioxide. Journal of the Electrochemical Society 134, 638-647. 

Normally, aldosterone exerts its mineralocorticoid actions via interaction with its receptors —>T formation of Na+ channels on the luminal membrane of the principal cell and — T activity of Na+/K+ and II1 exchangers. Na+ diffuses through its channels, increasing intracellular positive charge, which leads to extrusion of K+ into the lumen. By mechanisms that are unclear, Na+ entry into cells of the CT leads to an increase in the energy-dependent extrusion of protons across the luminal membranes of intercalated cells. 

Ultrastructural and immunohistochemical features of ChromRCC point to differentiation toward the intercalated cells of renal collecting ducts (Table 16.15). 1 3,358-360,362,383,384,394,410-416... 

DCT=distal convoluted tubule cell CD-PC=collecting duct principal cell CD-IC=collecting duct intercalated cell. 

---