Na+/H+ exchangers in the human eccrine sweat duct

2003 ◽  
Vol 285 (5) ◽  
pp. C1047-C1058 ◽  
Author(s):  
D. Granger ◽  
M. Marsolais ◽  
J. Burry ◽  
R. Laprade
Keyword(s):  
Ph Regulation ◽  
Basolateral Membrane ◽  
Outer Cell ◽  
Sweat Duct ◽  
Sodium Removal ◽  
Luminal Membrane ◽  
Strong Staining ◽  
Outer Cell Layer ◽  
Eccrine Sweat

Using an anti-NHE1 antibody, we demonstrate the presence of a Na+/H+ exchanger of isoform 1 (NHE1) in the human eccrine sweat duct. A strong staining was observed at the basolateral membrane of the outer cell layer (NHE1basal), at the junction between inner and outer cells layers (NHE1inter), and along the lateral membranes (NHE1later) of all cells of the duct. At the luminal membrane, no staining was demonstrated either for NHE1 or NHE3. To investigate Na+/H+ mediated proton transport, straight sweat duct portions were isolated and perfused in vitro under HCO3--free conditions. In the presence of basolateral 5-ethyl- N-isopropyl amiloride (EIPA), an acidification of 0.29 ± 0.03 pH units was observed, whereas no effect was observed with luminal EIPA. Bath sodium removal generated a stronger acidification (0.41 ± 0.09 pH units). Removal of luminal sodium (in the absence or presence of basolateral EIPA), or low luminal chloride, led to an alkalinization, presumably due to a decrease in intracellular sodium, strongly suggesting functional activity of NHE1inter. We therefore conclude that in the sweat duct, NHE1 plays a major role in intracellular pH regulation.

Evidence for active dipeptide transport in isolated proximal straight tubules

1988 ◽  
Vol 255 (1) ◽  
pp. F177-F181 ◽  
Author(s):  
D. W. Barfuss ◽  
V. Ganapathy ◽  
F. H. Leibach
Keyword(s):  
Basolateral Membrane ◽  
Rabbit Kidney ◽  
Luminal Membrane ◽  
Appearance Rate ◽  
Metabolic Products ◽  
Straight Tubules ◽  
Liquid Chromatographic Analysis ◽  
Dipeptide Transport ◽  
Liquid Chromatographic

Transport of the dipeptide glycylsarcosine (Gly-Sar) was examined in isolated proximal straight tubules of the rabbit kidney by an in vitro microperfusion technique to determine whether it can be actively transported intact. The unidirectional lumen-to-bath flux of Gly-Sar was measured by two separate methods, namely its appearance rate (JA) in the bathing fluid and its disappearance rate (JD) from the luminal fluid. In addition, the cell Gly-Sar concentration was measured immediately after the last flux period. Mean luminal fluid Gly-Sar concentration was 0.22 mM. Transepithelial Gly-Sar flux (260.0 fmol.min-1.mm-1) was greater than could be accounted for by passive leakage, whereas cellular Gly-Sar accumulation (2.72 mM) was greater than could be attributed to passive equilibration across the luminal membrane. High-pressure liquid chromatographic analysis of cellular extract indicated that 63% of the transported Gly-Sar was hydrolyzed within the cell. Analysis of the bath solution revealed that 47% of the radioactivity that crossed the tubule cell was in the form of intact dipeptide, whereas the remainder of the radioactivity was in the form of hydrolytic and metabolic products of Gly-Sar. This indicates that the dipeptide Gly-Sar is actively transported intact at the luminal membrane into the cytosol of proximal straight tubule cells with subsequent hydrolysis. It then exits across the basolateral membrane as intact Gly-Sar and its hydrolytic and metabolic products.

Insulin stimulates NaCl transport in isolated perfused MTAL of Henle's loop of rabbit kidney

1994 ◽  
Vol 267 (2) ◽  
pp. F265-F270 ◽  
Author(s):  
O. Ito ◽  
Y. Kondo ◽  
N. Takahashi ◽  
K. Kudo ◽  
Y. Igarashi ◽  
...  
Keyword(s):  
Kinase Inhibitor ◽  
Basolateral Membrane ◽  
Rabbit Kidney ◽  
Thick Ascending Limb ◽  
Maximal Effect ◽  
Nacl Transport ◽  
Luminal Membrane ◽  
Camp Analogue

To elucidate the mechanism of Na+ retention by insulin in vivo, the direct tubular effect of insulin on NaCl transport in the in vitro microperfused medullary thick ascending limb of Henle (MTAL) was examined. Insulin at 10(-6) mol/l in the bath increased transepithelial voltage (Vte) from 3.1 +/- 0.3 to 5.7 +/- 0.3 mV (n = 12, P < 0.0001). The effect of insulin on Vte was dependent on its concentration, and the half-maximal effect of insulin was observed at 5 x 10(-9) mol/l. Insulin at 10(-6) mol/l also caused a significant decrease of luminal Cl- concentration from 85.4 +/- 5.0 to 62.8 +/- 3.0 mmol/l (n = 5, P < 0.002) when the lumen was microperfused constantly at less than 1 nl/min. Insulin at 10(-6) mol/l also increased net lumen-to-bath Cl- flux (JCl) from 143 +/- 15 to 292 +/- 37 pmol.mm-1.min-1 (n = 5, P < 0.004). When the Na(+)-K(+)-adenosinetriphosphatase (Na(+)-K(+)-ATPase) in the basolateral membrane was blocked by 10(-4) mol/l ouabain, the insulin-mediated increase in Vte was completely suppressed. When the Na(+)-K(+)-2Cl- cotransporter in the luminal membrane of the MTAL was blocked by 10(-4) mol/l furosemide, the insulin-mediated increase in Vte was also abolished. To test whether adenosine 3',5'-cyclic monophosphate (cAMP) contributes to the action of insulin, we examined the effect of cAMP analogue and cAMP-dependent protein kinase inhibitor on the action of insulin. A maximal concentration (5 x 10(-4) mol/l) of dibutyryl-cAMP (DBcAMP) increased Vte and JCl.(ABSTRACT TRUNCATED AT 250 WORDS)

V-type H+-ATPase in the human eccrine sweat duct: immunolocalization and functional demonstration

2002 ◽  
Vol 282 (6) ◽  
pp. C1454-C1460 ◽  
Author(s):  
D. Granger ◽  
M. Marsolais ◽  
J. Burry ◽  
R. Laprade
Keyword(s):  
Apical Membrane ◽  
Staining Pattern ◽  
Specific Inhibitor ◽  
Sweat Duct ◽  
Proton Extrusion ◽  
Cold Preservation ◽  
Concanamycin A ◽  
Acid Load ◽  
Strong Staining ◽  
Eccrine Sweat

We investigated for the presence of a vacuolar-type H+-ATPase (V-ATPase) in the human eccrine sweat duct (SD). With the use of immunocytochemistry, an anti-V- ATPase antibody showed a strong staining at the apical membrane and a weaker one in the cytoplasm. Cold preservation followed by rewarming did not alter this staining pattern. With the use of the pH-sensitive dye 2′,7′-bis(2-carboxyethyl)-5(6)-carboxyfluorescein on isolated and perfused straight SD under HCO[Formula: see text]-free conditions and in the absence of Na+, proton extrusion was determined from the recovery rate of intracellular pH (dpHi/d t) following an acid load. Oligomycin (25 μM), an inhibitor of F-type ATPases, decreased dpHi/d t by 88 ± 6%, suggesting a role for an ATP-dependent process involved in pHi recovery. Moreover, dpHi/d t was inhibited at 95 ± 3% by 100 nM luminal concanamycin A, a specific inhibitor of V-ATPases, whereas 10 μM bafilomycin A1, another specific inhibitor of V-ATPases, was required to decrease dpHi/d t by 73%. These results strongly suggest that a V-ATPase is involved in proton secretion in the human eccrine SD.

scholarly journals Lack of response of INT-407 cells to the presence of non-culturableCampylobacter jejuni

2007 ◽  
Vol 136 (10) ◽  
pp. 1401-1406 ◽  
Author(s):  
L. VERHOEFF-BAKKENES ◽  
W. C. HAZELEGER ◽  
M. H. ZWIETERING ◽  
R. De JONGE
Keyword(s):  
Campylobacter Jejuni ◽  
Cell Layer ◽  
Potential Effect ◽  
Outer Cell ◽  
Culturable Bacteria ◽  
Small Intestines ◽  
Outer Cell Layer ◽  
Number Of Bacteria

SUMMARYMany contradictory articles on the infectivity of non-culturableCampylobacter jejunican be found. We studied the effect of non-culturableC. jejuniin anin vitroassay. To prevent the potential effect of a few culturable bacteria in the non-culturable suspension, INT-407 cells, which mimic the outer cell layer in the small intestines, were exposed to culturableC. jejunisuspensions with or without non-culturableC. jejuni. The number of bacteria adhering to and/or invading INT-407 cells and the IL-8 secretion were measured. No differences were found between bacterial suspensions with or without non-culturableC. jejuniadded. These findings show that non-culturableC. jejunido not adhere to or invade INT-407 cells and do not induce an immune response. As previous studies showed a correlation between the usedin vitroassays and the effectin vivo, our study strongly suggests that culturability is a good indicator of the risk forC. jejuniinfection.

Embryonic development of the heart

Development ◽  
1969 ◽  
Vol 22 (3) ◽  
pp. 333-348
Author(s):  
Francis J. Manasek
Keyword(s):  
Cell Layer ◽  
Embryonic Heart ◽  
Outer Cell ◽  
Chick Embryos ◽  
Myocardial Wall ◽  
Undifferentiated Cells ◽  
Epicardial Layer ◽  
Outer Cell Layer ◽  
Heart Wall

The mature heart may be thought of as consisting of three layers, endocardium, myocardium, and an outer investing tissue called the epicardium. During early formation of the tubular heart of chick embryos, at about the 8-somite stage, two tissue layers become clearly discernible with the light microscope: the endocardium and the developing myocardial wall. The outer epicardial layer does not appear until later in development. It is generally accepted that embryonic heart wall or ‘epimyocardium’ is composed of muscle and undifferentiated cells. As its name implies, the epimyocardium is thought to give rise to myocardium and epicardium. Kurkiewicz (1909) suggested that the epicardium was not an epimyocardial derivative but rather is formed from cells originating in the sinus venosus region, which migrate over the surface of the heart. Nevertheless, it has become generally accepted that the outer cell layer of the embryonic heart wall differentiates in situ to give rise to the definitive visceral epicardium (Patten, 1953).

Pharmacological profile of antihistamines: focus on unwanted drug interactions

2021 ◽  
Vol 17 (4) ◽  
pp. 46-56
Author(s):  
Alexander S. Dukhanin
Keyword(s):  
Drug Interactions ◽  
Second Generation ◽  
The Body ◽  
Pharmacological Profile ◽  
Luminal Membrane ◽  
Pharmacokinetic Properties ◽  
System 2 ◽  
Specific Affinity ◽  
Histamine H1 Receptors

Differences between individual antihistamines are determined by such pharmacokinetic properties as the rate and completeness of absorption, half-life, the participation of hepatic and renal mechanisms of elimination from the body. Pharmacodynamic features of the antihistamine include selectivity and affinity for histamine H1-receptors and the presence of central effects. The mechanisms of the development of unwanted drug interactions with second-generation antihistamines are analyzed in detail. Three levels of interaction have been identified: 1) hepatic enzymes of the P450 system; 2) membrane carriers of organic anions (OATP) transport proteins on the sinusoidal membrane of hepatocytes and the luminal membrane of the epithelium of the proximal nephron tubule; 3) P-glycoprotein (Pgp, ABCB1-protein) of epithelial cells of the small intestine the area of absorption of oral forms of antihistamines, the epithelium of the proximal tubule and the BBB (blood-brain barrier). The emphasis is made on the description of the dependence of the pharmacological profile of antihistamines on its chemical structure. The elasticity of the bilastine molecule, the ability to induce a change in conformation underlies the high complementarity of bilastine to the recognition site of the H1-receptor which is a high affinity. Experimental evaluation confirms this conclusion: the dissociation constant (Dс) of the bilastin-receptor complex is in the nM concentration range. The bilastine molecule, as a representative of antihistamines with zwitterionic properties, carries both a positive and a negative charge at a physiological pH, making it difficult for its penetration into the brain. The peculiarities of the chemical nature of the bilastine molecule are reflected in the specific pharmacological profile of AGP. In vitro studies have shown a high specific affinity of bilastine for H1-receptors with a very low affinity for other histamine receptors (H2, H3, H4), serotonin, bradykinin, muscarinic and adrenergic receptors). According to this indicator, bilastine is 3 times higher than cetirizine and 5 times higher than fexofenadine. Bilastine is practically not metabolized in the body and is excreted mainly unchanged, and also does not have a cardiotoxic effect. Bilastine is well tolerated; as a therapeutic dose it has a less pronounced sedative potential compared to other second-generation antihistamines.

Absence of a cAMP-mediated antiabsorptive effect in an undifferentiated jejunal epithelium

1987 ◽  
Vol 252 (6) ◽  
pp. G776-G782
Author(s):  
R. J. MacLeod ◽  
J. R. Hamilton
Keyword(s):  
Small Intestine ◽  
Thymidine Kinase ◽  
Jejunal Mucosa ◽  
Ussing Chambers ◽  
Luminal Membrane ◽  
Viral Enteritis ◽  
Transmissible Gastroenteritis ◽  
Camp Levels ◽  
Nacl Cotransport

In the relatively undifferentiated jejunal mucosa occurring in piglet viral enteritis, we measured the response of transepithelial Na+ and Cl- fluxes in vitro to raised intracellular adenosine 3',5'-cyclic monophosphate (cAMP) levels. At the acute 40-h stage of transmissible gastroenteritis (TGE), luminal membrane markers, sucrase and lactase, and a basolateral jejunal epithelial membrane marker Na+-K+-ATPase, were significantly decreased in activity, while a proliferative marker, thymidine kinase, was significantly enriched; these enzyme characteristics are typical of enterocytes isolated from crypts of other species. As expected, control piglet jejunum in short-circuited Ussing chambers after theophylline (10 mM) developed significant net secretory Na and Cl fluxes primarily due to significant antiabsorptive effects (delta JNa m----s = 3.48 +/- 0.52, delta JCl m----s = 2.59 +/- 0.28). Furosemide (10(-4) M), an inhibitor of electroneutral NaCl cotransport, produced antiabsorptive effects (delta JNa m----s = 2.53 +/- 0.31, delta JCl m----s = 2.58 +/- 0.28) in control jejunum that were not significantly different from those seen in response to theophylline. TGE jejunum, however, responded to theophylline not by an antiabsorptive effect but by significant electrogenic Cl- secretion (delta JCl s----m = 1.59 +/- 0.48); furosemide had no effect on ion fluxes in TGE tissue. Control and TGE jejunal mucosal homogenates did not differ in their basal or theophylline-stimulated levels of cAMP. We conclude that the relatively undifferentiated small intestine occurring in acute TGE does not generate either a cAMP-mediated antiabsorptive effect or a furosemide-mediated antiabsorptive effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Experimental Cystinuria: the Cycloleucine Model. I. Amino Acid Interactions in Renal and Intestinal Epithelia

1975 ◽  
Vol 53 (6) ◽  
pp. 1027-1036 ◽  
Author(s):  
André G. Craan ◽  
Michel Bergeron
Keyword(s):  
Amino Acids ◽  
Renal Tubules ◽  
Intestinal Epithelia ◽  
Luminal Membrane ◽  
Luminal Side ◽  
Convoluted Tubules ◽  
Dibasic Amino Acids ◽  
Everted Sacs

The injection of cycloleucine (1-aminocyclopentanecarboxylic acid (ACPC)) into rats produces a hyperexcretion of dibasic amino acids and cystine, an aberration resembling cystinuria. This may constitute a model of experimental cystinuria, and the transport of amino acids involved in this disease was studied with the techniques of everted intestinal sacs (in vitro) and microinjections into renal tubules (in vivo). In everted sacs from normal rats, there was a decrease in transfer and in accumulation of L-cystine (0.03 mM), L-lysine (0.065 mM) and L-valine (0.065 mM) when ACPC was on the mucosal (luminal) side. Dibasic amino acids such as L-ariginine and L-lysine caused a similar inhibition of the transport of L-cystine. However, when ACPC was on the serosal (antiluminal) side, a lesser effect was noted while arginine and lysine had no effect. Intestinal sacs from treated rats (ACPC, 300 mg/kg × 3 days) transferred and accumulated as much L-cystine as those from control rats. The interaction between cycloleucine and L-cystine was competitive at the luminal and non-competitive at the antiluminal side of the intestine. Cycloleucine inhibited L-lysine transport in a non-competitive fashion at either side of the intestine. L-Lysine also interacted in a non-competitive fashion with L-cystine transport at the luminal membrane. In proximal convoluted tubules, the presence of L-arginine or ACPC caused a decrease in the transport of L-cystine and L-lysine. L-Valine exerted no effect. Furthermore, L-lysine and ACPC did not impair the reabsorption of L-valine significantly.These results suggest a functional heterogeneity between luminal and antiluminal membranes of renal and intestinal epithelia and the existence, at both membranes, of different transport sites for cystine and dibasic amino acids.

Regulation of electrolyte and fluid secretion in salivary acinar cells

1992 ◽  
Vol 263 (6) ◽  
pp. G823-G837 ◽  
Author(s):  
B. Nauntofte
Keyword(s):  
Ionic Composition ◽  
Basolateral Membrane ◽  
Acinar Cells ◽  
Fluid Secretion ◽  
Receptor Activation ◽  
Exchange Mechanism ◽  
Luminal Membrane ◽  
Net Uptake ◽  
Cl Channels ◽  
Simultaneous Activation

The primary secretion from exocrine gland cells is a fluid rich in Na+ and Cl- with a plasmalike ionic composition. Activation of specific receptors on the plasma membrane by hormones and neurotransmitters, which leads to activation of the phosphoinositol metabolism, results in release of Ca2+ from internal Ca2+ stores. Intracellular free Ca2+ concentration ([Ca2+]i) then rises simultaneously at both the basolateral and luminal parts of the acinar cell, reaching maximum values within 1 s after stimulation. In parotid acinar cells, increased [Ca2+]i activates the opening of maxi K+ channels located on the basolateral membrane and Cl- channels presumably located on the luminal membrane, resulting in rapid loss of K+ and Cl- and water and cell shrinkage. Extracellular electroneutrality is maintained by a paracellular Na+ flux into the lumen. Because of the simultaneous activation of K+ and Cl- channels, secretion occurs at a virtually constant membrane potential of about -60 mV. After maximal muscarinic cholinergic stimulation, loss of K+, Cl-, and water results in an approximate 25% reduction in cell volume within 10-15 s after receptor activation. Concomitant with loss of Cl-, there is a loss of HCO3- from the cell, causing a decrease in intracellular pH of 0.1 pH units because of the carbonic anhydrase-mediated conversion of CO2 into H+ and HCO3-. H+ generated from the metabolism and HCO3- production is compensated for by extrusion of H+ by a Na(+)-H+ exchange mechanism, which is responsible for approximately 75% of net Na+ gain that occurs after stimulation. Increased [Na+]i activates the Na(+)-K+ pump, which in turn extrudes Na+ from the cells. In both the unstimulated and stimulated states, cellular production of HCO3- can drive a net uptake of Cl- via the Cl(-)-HCO3- exchange mechanism operating in parallel with the Na(+)-H+ exchanger. The operation of the Cl(-)-HCO3- exchanger is, together with a Na(+)-K(+)-2Cl- cotransport system, essential for maintainance of a high [Cl-]i both in the unstimulated state and during Cl- reuptake.

Pharmacologic responsiveness of isolated single eccrine sweat glands

1981 ◽  
Vol 240 (1) ◽  
pp. R44-R51 ◽  
Author(s):  
K. Sato ◽  
F. Sato
Keyword(s):  
Dose Response ◽  
Dissociation Constants ◽  
Sweat Rate ◽  
Sweat Glands ◽  
Adrenergic Agonist ◽  
Beta Adrenergic ◽  
Adrenergic Agents ◽  
Eccrine Sweat Glands ◽  
Eccrine Sweat

Pharmacologic responsiveness of the eccrine sweat gland has never been studied under well-defined in vitro experimental conditions. Using isolated cannulated single monkey palm eccrine sweat glands, the dose response to both cholinergic and alpha- and beta-adrenergic agents and the effects of various antagonists on agonists were studied. The maximal sweat rate was highest after stimulation with cholinergic agonists, was lower with the beta-adrenergic agonist, and was least with the alpha-adrenergic agonist. Each secretory response was inhibited by its specific antagonist. Attempts to demonstrate the spare receptor, if any, by means of preincubation of the glands with N-(2-chlorethyl)dibenzylamine (Dibenamine) were unsuccessful. From the hyperbolic dose-response curves the values for KA and KB, dissociation constants for agonists and antagonists, respectively, were thus tentatively estimated according to Clark's classical receptor theory. Schild plots for each agonist-antagonist interaction produced straight lines with slopes of near unity, indicating the adequacy of the methodology. It was concluded that the isolated eccrine sweat glands retain their pharmacologic viability in vitro and show responsiveness to cholinergic as well as both alpha- and beta-adrenergic stimulations.

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