Fluid Reabsorption by the Ductuli Efferentes Testis of the Rat Is Dependent on Both Sodium and Chlorine1

Hansen, Lyall A.; Dacheux, Françoise; Man, S Y; Clulow, John; Jones, Russell C.

doi:10.1095/biolreprod.104.027490

Cited by 14 publications

(12 citation statements)

References 44 publications

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“…In addition, the anion transporter SLC26A3 has recently been located in these cells in human , enabling the proposed model of paired function of SLC26A3 and A6, activated by CFTR (Ko et al 2002). Our results further coincide with the previous functional data from rat indicating that major absorption of Cl K , Na C , and water in the efferent ducts is mediated by an apical Cl K =HCO K 3 exchanger, acting in parallel with a Na C /H C antiporter (Hansen et al 2004). Thus, we propose a model that in human efferent ducts, SLC26A3 and A6 work in conjunction with CFTR to secret HCO K 3 and absorb Cl K , and this action is further facilitated by the Na C absorption of the Na C /H C exchanger NHE3.…”

Section: Discussionsupporting

confidence: 89%

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Kujala¹,

Hihnala²,

Tienari³

et al. 2007

Reproduction

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Appropriate intraluminal microenvironment in the epididymis is essential for maturation of sperm. To clarify whether the anion transporters SLC26A2, SLC26A6, SLC26A7, and SLC26A8 might participate in generating this proper intraluminal milieu, we studied the localization of these proteins in the human efferent and the epididymal ducts by immunohistochemistry. In addition, immunohistochemistry of several SLC26-interacting proteins was performed: the Na C /H C exchanger 3 (NHE3), the Cl K channel cystic fibrosis transmembrane conductance regulator (CFTR), the proton pump V-ATPase, their regulator Na C /H C exchanger regulating factor 1 (NHERF-1), and carbonic anhydrase II (CAII). Our results show that SLC26A6, CFTR, NHE3, and NHERF-1 are co-expressed on the apical side of the nonciliated cells, and SLC26A2 appears in the cilia of the ciliated cells in the human efferent ducts. In the epididymal ducts, SLC26A6, CFTR, NHERF-1, CAII, and V-ATPase (B and E subunits) were co-localized to the apical mitochondria rich cells, while SLC26A7 was expressed in a subgroup of basal cells. SLC26A8 was not found in the structures studied. This is the first study describing the localization of SLC26A2, A6 and A7, and NHERF-1 in the efferent and the epididymal ducts. Immunolocalization of human CFTR, NHE3, CAII, and V-ATPase in these structures differs partly from previous reports from rodents. Our findings suggest roles for these proteins in male fertility, either independently or through interaction and reciprocal regulation with co-localized proteins shown to affect fertility, when disrupted. Reproduction (2007) 133 775-784

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Section: Discussionsupporting

confidence: 89%

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Kujala¹,

Hihnala²,

Tienari³

et al. 2007

Reproduction

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“…Ion substitution is a commonly used method to study channel properties in the field of ion channel research (Keramidas et al, 2002;Hansen et al, 2004;Lai et al, 2004). For example, aspartate (Asp -) and glutamate (Glu -) have been used to replace Cl -to study the transient outward K channel in rat ventricular myocytes (Lai et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Overexpression of claudin-7 decreases the paracellular Cl– conductance and increases the paracellular Na+ conductance in LLC-PK1 cells

Alexandre

Lü

Chen

2005

Journal of Cell Science

185

125

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Tight junctions form the primary barrier regulating the diffusion of fluid, electrolytes and macromolecules through the paracellular pathway. Claudins are the major structural and functional components of tight junction strands and are considered as the best candidates for forming paracellular channels. They are a family of integral membrane proteins with more than 20 members and show distinct tissue distribution patterns. In this study, we found that claudin-7 is expressed in the distal and collecting tubules and the thick ascending limb of Henle of porcine and rat kidneys. To investigate the role of claudin-7 in paracellular transport, we have overexpressed a mouse claudin-7 construct in LLC-PK1 cells. Overexpression of claudin-7 did not affect the expression and localization of endogenous claudin-1, -3, -4, -7, and ZO-1. However, transepithelial electrical resistance in claudin-7-overexpressing cells was greatly increased. In addition, electrophysiological measurements revealed a dramatic reduction of dilution potentials in claudin-7-overexpressing cells compared to that of control cells. To determine which ions are responsible for the effects of claudin-7 overexpression on transepithelial electrical resistance and dilution potentials, we applied an ion substitution strategy. When NaCl was replaced with sodium aspartate, transepithelial electrical resistance was significantly decreased and dilution potentials were increased in claudin-7-overexpressing cells as compared to controls, the opposite effects from that of using NaCl. Furthermore, when NaCl was substituted by arginine-HCl or lysine-HCl, the increase in transepithelial electrical resistance was greater and the reduction in dilution potentials was smaller. Taken together, our studies demonstrated for the first time that the effect of claudin-7 overexpression in LLC-PK1 cells on paracellular transport is mediated through a concurrent decrease in the paracellular conductance to Cl– and an increase in the paracellular conductance to Na+. These results support the model that claudin-7 may form a paracellular barrier to Cl– while acting as a paracellular channel to Na+.

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“…The ciliated and nonciliated cells present in rat efferent ductules are capable of modifying the composition of the luminal fluid by endocytosis (Hermo et al 1985;Robaire and Hermo 1988;Ilio and Hess 1994;Clulow et al 1994Clulow et al , 1996Clulow et al , 1998Hansen et al 2004). The diffuse immunostaining for M 1 mAChR observed in the ciliated and nonciliated cells and the presence of M 2 and M 3 mAChRs mainly in the ciliated cells suggest that these receptors are involved in the regulation of cellular functions.…”

Section: Discussionmentioning

confidence: 99%

Expression and localization of muscarinic acetylcholine receptor subtypes in rat efferent ductules and epididymis

et al. 2005

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The expression of muscarinic acetylcholine receptor (mAChR) subtypes (M(1)-M(5)) was studied in the rat efferent ductules and epididymis at the mRNA and protein levels. The relative abundance of each mAChR transcript subtype differed depending on the tissue and the epididymal region analyzed. The M(1) mAChR mRNA level was more abundant in the efferent ductules than in the caput and cauda of the epididymis. The M(2) mAChR mRNA level was similar between the efferent ductules and caput of the epididymis and higher in the cauda region. The M(3) mAChR mRNA level was low in the efferent ductules and caput of the epididymis, but high levels were detected in the cauda region. mRNAs for M(4) and M(5) mAChRs were not detected in these tissues. Our studies indicated a variable degree of immunostaining for each mAChR subtype in a cell-type and tissue-specific pattern. M(1) mAChR was detected over the efferent ductule epithelium. M(2) and M(3) mAChRs were observed in the apical region of the ciliated cells. Apical and narrow cells of the initial segment showed distinct staining by M(1) antibody, whereas a supranuclear reaction was noted in the principal cells of the caput of the epididymis. In addition, staining for M(1) and M(2) mAChRs was visible in the apical membrane of some epithelial cells of the cauda region. M(3) mAChR was detected in the peritubular smooth muscle of the efferent ductules and epididymis. Functional studies suggested the involvement of this subtype in epididymal tubule contraction. Thus, the cell-specific expression of the various mAChR subtypes in the efferent ductules and epididymis suggests that these receptors play a role in the modulation of luminal fluid composition and smooth muscle contraction.

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Fluid Reabsorption by the Ductuli Efferentes Testis of the Rat Is Dependent on Both Sodium and Chlorine1

Cited by 14 publications

References 44 publications

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Expression of ion transport-associated proteins in human efferent and epididymal ducts

Overexpression of claudin-7 decreases the paracellular Cl– conductance and increases the paracellular Na+ conductance in LLC-PK1 cells

Expression and localization of muscarinic acetylcholine receptor subtypes in rat efferent ductules and epididymis

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