Muscarinic Agonists Induce Phosphorylation-independent Activation of the NHE-1 Isoform of the Na+/H+ Antiporter in Salivary Acinar Cells

Robertson, M A; Woodside, Michael; Foskett, J. Kevin; Orlowski, John; Grinstein, Sergio

doi:10.1074/jbc.272.1.287

Cited by 46 publications

(42 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In addition to these uncertainties concerning isoform localization, very little is known about the specific functions of the individual NHE isoforms in acinar cells during resting conditions or when stimulated to secrete fluid. Available evidence suggests that the most highly expressed Na ϩ /H ϩ exchanger in acinar cells is probably the NHE1 isoform (23)(24)(25). However, the mechanisms involved in the upregulation of Na ϩ /H ϩ exchanger activity in salivary acinar cells are inconsistent with the known properties of expressed NHE1.…”

mentioning

confidence: 71%

See 1 more Smart Citation

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Evans¹,

Bell²,

Schultheis³

et al. 1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

The onset of salivary gland fluid secretion in response to muscarinic stimulation is accompanied by up-regulation of Na ؉ /H ؉ exchanger (NHE) activity. Although multiple NHE isoforms (NHE1, NHE2, and NHE3) have been identified in salivary glands, little is known about their specific function(s) in resting and secreting acinar cells. Mice with targeted disruptions of the Nhe1, Nhe2, and Nhe3 genes were used to investigate the contribution of these proteins to the stimulation-induced up-regulation of NHE activity in mouse parotid acinar cells. The lack of NHE1, but not NHE2 or NHE3, prevented intracellular pH recovery from an acid load in resting acinar cells, in acini stimulated to secrete with the muscarinic agonist carbachol, and in acini shrunken by hypertonic addition of sucrose. In HCO 3 ؊ -containing solution, the rate of intracellular pH recovery from a muscarinic agoniststimulated acid load was significantly inhibited in acinar cells from mice lacking NHE1, but not in cells from NHE2-or NHE3-deficient mice. These data demonstrate that NHE1 is the major regulator of intracellular pH in both resting and muscarinic agonist-stimulated acinar cells and suggest that up-regulation of NHE1 activity has an important role in modulating saliva production in vivo.

show abstract

mentioning

confidence: 71%

“…Recently, a combination of immunocytochemical, pharmacological, and molecular biological studies have shown that rat parotid and submandibular acini express NHE1 in their basolateral membrane (22)(23)(24)(25). In contrast, the subcellular distribution of NHE2 and NHE3 appears to be species-and glandspecific (22,24,25).…”

mentioning

confidence: 99%

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Evans¹,

Bell²,

Schultheis³

et al. 1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…However, with NHE4-specific primers encoding cDNA sequences of the highly homologous predicted transmembane domains 5 and 5b (Orlowski et al 1992), a 203-bp fragment identical to the NHE4 cDNA sequence reported by Orlowski et al was detected in pancreas and kidney cDNA (Anderie et al 1998). Interestingly, Robertson et al (1997) also failed to PCR-amplify NHE4 by RT-PCR from parotid cDNA with primers encoding the cytosolic region of NHE4, but with NHE4-specific primers from the transmembrane regions 5 and 5b, we obtained an NHE4 cDNA fragment from parotid tissue (not shown). Our results, together with the data from Robertson et al (1997), indicate that it is impossible to amplify NHE4 from pancreas or parotid gland with primers coding for the C-terminal region of NHE4 and may account for the difference between our results and those of Lee et al (2000).…”

Section: Nhe1 and Nhe4mentioning

confidence: 99%

“…Interestingly, Robertson et al (1997) also failed to PCR-amplify NHE4 by RT-PCR from parotid cDNA with primers encoding the cytosolic region of NHE4, but with NHE4-specific primers from the transmembrane regions 5 and 5b, we obtained an NHE4 cDNA fragment from parotid tissue (not shown). Our results, together with the data from Robertson et al (1997), indicate that it is impossible to amplify NHE4 from pancreas or parotid gland with primers coding for the C-terminal region of NHE4 and may account for the difference between our results and those of Lee et al (2000). One explanation could be that the 3Ј-reverse primers ("C-stop", "Crev1", and "C-rev2"; see Figure 4A) deduced from the base sequence encoding the carboxy-terminal region of rat stomach NHE4 cDNA (Orlowski et al 1992) do not match the 3Ј-terminal base sequence of rat pancreatic NHE4.…”

Section: Nhe1 and Nhe4mentioning

confidence: 99%

Immunolocalization of Anion Exchanger AE2, Na⁺/H⁺ Exchangers NHE1 and NHE4, and Vacuolar Type H⁺-ATPase in Rat Pancreas

Roussa

Alper

Thévenod

2001

J Histochem Cytochem.

View full text Add to dashboard Cite

S U M M A R YWe have studied the expression and localization of several H ϩ and HCO 3 Ϫ transporters, whose presence in the rat pancreas is still unclear. The Cl Ϫ /HCO 3 Ϫ exchanger AE2, the Na ϩ /H ϩ exchangers NHE1 and NHE4, and the 31-kD and 70-kD vacuolar H ϩ -ATPase (V-ATPase) subunits were detected by immunoblotting and immunocytochemical techniques. Immunoblotting of plasma membranes with transporter-specific antibodies revealed protein bands at Ϸ 160 kD for AE2, at Ϸ 90 kD and Ϸ 103 kD for NHE1 and NHE4, respectively, and at 31 kD and 70 kD for V-ATPase. NHE1 and NHE4 were further identified by amplification of isoform-specific cDNA using RT-PCR. Immunohistochemistry revealed a basolateral location of AE2, NHE1, and NHE4 in acinar cells. In ducts, NHE1 and NHE4 were basolaterally located but no AE2 expression was detected. V-ATPase was detected in zymogen granules (ZGs) by immunogold labeling, and basolaterally in duct cells by immunohistochemistry. The data indicate that NHE1 and NHE4 are co-expressed in rat pancreatic acini and ducts. Basolateral acinar AE2 could contribute to Cl Ϫ uptake and/or pH regulation. V-ATPase may be involved in ZG fusion/exocytosis and ductal HCO 3 Ϫ secretion. The molecular identity of the ductal Cl Ϫ /HCO 3 Ϫ exchanger remains unclear.

show abstract

“…There are many reports on NHE activation, and an increase in [Ca 2ϩ ] i activates NHE exchange in salivary gland Turner, 1990, 1991). Later the Ca 2ϩ -calmodulin complex was proposed to activate NHE, because no additional phosphorylation occurred in response to muscarinic stimulation in salivary gland (Robertson et al, 1997). In addition, intracellular Na ϩ concentration sensing mechanisms have been discussed (Ishibashi et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Cevimeline-Induced Monophasic Salivation from the Mouse Submandibular Gland: Decreased Na⁺Content in Saliva Results from Specific and Early Activation of Na⁺/H⁺Exchange

Kondo

Nakamoto²,

Mukaibo³

et al. 2011

J Pharmacol Exp Ther

View full text Add to dashboard Cite

Cevimeline and pilocarpine are muscarinic agonists used clinically to treat dry mouth. In this study, we explored fluid secretion from mouse submandibular glands to determine the mechanism of cevimeline, pilocarpine, and an experimentally used agent carbachol. Cevimeline evoked almost the same amount of secretion at concentrations from 30 M to 1 mM. Pilocarpine also induced secretion at a concentration as low as 1 M and was the most powerful secretagogue at 10 M. Secretion was induced by carbachol at 0.1 M, with maximum secretion at 1.0 M. Cevimeline induced monophasic secretion at all concentrations tested, whereas higher concentrations of pilocarpine and carbachol induced secretion with variable kinetics, i.e., an initial transient high flow rate, followed by decreased secretion after 2 to 3 min. In the presence of an epithelial Na ϩ channel blocker, amiloride, neither carbachol nor pilocarpine affected the Na ϩ level of secreted saliva; however, it significantly increased the Na ϩ content of cevimeline-induced saliva. The intracellular Ca 2ϩ response of acinar cells was almost identical among all three agents, although recovery after drug removal was slower for cevimeline and pilocarpine. A profound decrease in intracellular pH was observed during pilocarpine and carbachol treatment, whereas intracellular acidification induced by cevimeline was only seen in the presence of a Na ϩ /H ϩ exchange inhibitor. When external HCO 3 Ϫ was removed, cevimeline-induced saliva significantly decreased. These findings suggest that cevimeline specifically activates Na ϩ /H ϩ exchange and may promote Na ϩ reabsorption by stabilizing epithelial sodium channel activity.

show abstract

Muscarinic Agonists Induce Phosphorylation-independent Activation of the NHE-1 Isoform of the Na+/H+ Antiporter in Salivary Acinar Cells

Cited by 46 publications

References 34 publications

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Immunolocalization of Anion Exchanger AE2, Na⁺/H⁺ Exchangers NHE1 and NHE4, and Vacuolar Type H⁺-ATPase in Rat Pancreas

Cevimeline-Induced Monophasic Salivation from the Mouse Submandibular Gland: Decreased Na⁺Content in Saliva Results from Specific and Early Activation of Na⁺/H⁺Exchange

Contact Info

Product

Resources

About

Muscarinic Agonists Induce Phosphorylation-independent Activation of the NHE-1 Isoform of the Na+/H+ Antiporter in Salivary Acinar Cells

Cited by 46 publications

References 34 publications

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Targeted Disruption of the Nhe1 Gene Prevents Muscarinic Agonist-induced Up-regulation of Na+/H+ Exchange in Mouse Parotid Acinar Cells

Immunolocalization of Anion Exchanger AE2, Na+/H+ Exchangers NHE1 and NHE4, and Vacuolar Type H+-ATPase in Rat Pancreas

Cevimeline-Induced Monophasic Salivation from the Mouse Submandibular Gland: Decreased Na+Content in Saliva Results from Specific and Early Activation of Na+/H+Exchange

Contact Info

Product

Resources

About

Immunolocalization of Anion Exchanger AE2, Na⁺/H⁺ Exchangers NHE1 and NHE4, and Vacuolar Type H⁺-ATPase in Rat Pancreas

Cevimeline-Induced Monophasic Salivation from the Mouse Submandibular Gland: Decreased Na⁺Content in Saliva Results from Specific and Early Activation of Na⁺/H⁺Exchange