Targeted disruption of the Nhe1 gene fails to inhibit β1-adrenergic receptor-induced parotid gland hypertrophy

2001 ◽  
Vol 280 (4) ◽  
pp. G694-G700
Author(s):  
James E. Melvin ◽  
Ha-Van Nguyen ◽  
Keith Nehrke ◽  
Claire M. Schreiner ◽  
Kelly G. Ten Hagen ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Adrenergic Receptor ◽  
Acinar Cells ◽  
Receptor Activation ◽  
Parotid Glands ◽  
Targeted Disruption ◽  
Nhe1 Activity ◽  
Salivary Gland Hypertrophy ◽  
The Relationship

Chronic β1-adrenergic receptor activation results in hypertrophy and hyperplasia of rodent salivary gland acinar cells. Na+/H+ exchanger isoform 1 (NHE1) regulates cell volume and the induction of cell proliferation in many tissues. To investigate the relationship between NHE1 and the response of parotid glands to β1-adrenergic agonists, we examined by Northern blot analysis NHE1 expression in saline-treated mice and mice 30 min and 2, 6, and 24 h after isoproterenol injection. NHE1 transcripts increased ∼50% by 2 h, and a more than twofold increase was noted at 24 h. Isoproterenol did not acutely increase Na+/H+ exchanger activity; however, exchanger activity was significantly elevated by 24 h. To test whether NHE1 activity is essential for inducing salivary gland hypertrophy in vivo, mice with targeted disruption of Nhe1 were treated with isoproterenol. Na+/H+ exchanger activity was absent in acinar cells from Nhe1−/− mice, nevertheless, the lack of NHE1 failed to inhibit isoproterenol-induced hypertrophy. These data directly demonstrate that acinar cell hypertrophy induced by chronic β1-adrenergic receptor stimulation occurs independently of NHE1 activity.

scholarly journals Thiol-oxidation reduces the release of amylase induced by β-adrenergic receptor activation in rat parotid acinar cells

2010 ◽  
Vol 31 (5) ◽  
pp. 293-299 ◽  
Author(s):  
Ming-Yu Guo ◽  
Keitaro Satoh ◽  
Bing Qi ◽  
Takanori Narita ◽  
Osamu Katsumata-Kato ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Acinar Cells ◽  
Receptor Activation ◽  
Thiol Oxidation ◽  
Parotid Acinar Cells ◽  
Rat Parotid

scholarly journals Influence of dual ETA/ETB-receptor blockade on coronary responses to treadmill exercise in dogs

2000 ◽  
Vol 89 (5) ◽  
pp. 2041-2048 ◽  
Author(s):  
Masayuki Takamura ◽  
Robert Parent ◽  
Peter Cernacek ◽  
Michel Lavallée
Keyword(s):  
Coronary Sinus ◽  
Adrenergic Receptor ◽  
Left Ventricular Pressure ◽  
Receptor Activation ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Receptor Blockade ◽  
Etb Receptor ◽  
Dual Blockade ◽  
The Relationship

We hypothesized that endothelin (ET) release during exercise may be triggered by α-adrenergic-receptor activation and thereby influence coronary hemodynamics and O2 metabolism in dogs. Exercise resulted in coronary blood flow increases (to 1.88 ± 0.26 from 1.10 ± 0.12 ml · min−1 · g−1) and in a fall ( P < 0.01) in coronary sinus O2saturation (17.4 ± 1.5 to 9.6 ± 0.7 vol%), whereas myocardial O2 consumption (MV˙o 2) increased (109 ± 13% from 145 ± 16 μl O2 · min−1 · g−1). Tezosentan, a dual ETA/ETB-receptor blocker, slightly reduced mean arterial pressure (MAP) and increased heart rate throughout exercise. The relationship between coronary sinus O2 saturation and MV˙o 2 was shifted upward ( P < 0.05) after tezosentan administration; i.e., as MV˙o 2 increased during exercise, coronary sinus O2 saturation was disproportionately higher after ET-receptor blockade. After propranolol, tezosentan resulted in significant decreases ( P < 0.05) in left ventricular pressure, the first derivative of left ventricular pressure over time, and MAP during exercise. As MV˙o 2 increased during exercise, coronary sinus O2 saturation levels after tezosentan became superimposable over those observed before ET-receptor blockade. Thus dual blockade of ETA/ETBreceptors alters coronary hemodynamics and O2 metabolism during exercise, but ET activity failed to increase beyond baseline levels.

Platelet Shape Change Evoked by Selective Activation of P2X1 Purinoceptors with α,β-Methylene ATP

2001 ◽  
Vol 85 (02) ◽  
pp. 303-308 ◽  
Author(s):  
Michael Rolf ◽  
Charles Brearley ◽  
Martyn Mahaut-Smith
Keyword(s):  
Inhibitory Action ◽  
Light Transmission ◽  
Shape Change ◽  
Second Messengers ◽  
Receptor Activation ◽  
Selective Activation ◽  
The Relationship ◽  
Shape Changes ◽  
Platelet Shape

SummarySimultaneous measurements of [Ca2+]i and light transmission were used to examine the relationship between P2X1 receptor activation and functional platelet responses. The P2X1 agonist α,β-MeATP evoked a transient [Ca2+]i increase and a reversible decrease in light transmission; both responses required external Ca2+ and the nucleotidase apyrase. The transmission response was due to shape change only, verified by scanning electron microscopy and insensitivity to Reopro, a GPIIbIIIa antagonist. α,β-MeATP stimulated smaller shape changes than ADP, however P2X1 responses had a lifespan of <2 h following resuspension in saline and may be considerably larger in vivo. A peak [Ca2+]i increase of >50 nM was required for detectable shape change. Overlap of concentration-response relationships for α,β-MeATP-evoked [Ca2+]i and shape change suggests that other second messengers are not involved. Therefore, the physiological P2X1 agonist ATP can contribute to platelet activation, in contrast to its previously described inhibitory action at metabotropic platelet purinoceptors.

Functional and molecular characterization of the fluid secretion mechanism in human parotid acinar cells

2007 ◽  
Vol 292 (6) ◽  
pp. R2380-R2390 ◽  
Author(s):  
Tetsuji Nakamoto ◽  
Alaka Srivastava ◽  
Victor G. Romanenko ◽  
Catherine E. Ovitt ◽  
Patricia Perez-Cornejo ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Ion Transport ◽  
Acinar Cells ◽  
Fluid Secretion ◽  
K Channel ◽  
Resting Membrane Potential ◽  
Specific Cell ◽  
Parotid Glands ◽  
Voltage Dependent ◽  
Intracellular Ca

The strategies available for treating salivary gland hypofunction are limited because relatively little is known about the secretion process in humans. An initial microarray screen detected ion transport proteins generally accepted to be critically involved in salivation. We tested for the activity of some of these proteins, as well as for specific cell properties required to support fluid secretion. The resting membrane potential of human acinar cells was near −51 mV, while the intracellular [Cl−] was ∼62 mM, about fourfold higher than expected if Cl ions were passively distributed. Active Cl− uptake mechanisms included a bumetanide-sensitive Na+-K+-2Cl− cotransporter and paired DIDS-sensitive Cl−/HCO3− and EIPA-sensitive Na+/H+ exchangers that correlated with expression of NKCC1, AE2, and NHE1 transcripts, respectively. Intracellular Ca2+ stimulated a niflumic acid-sensitive Cl− current with properties similar to the Ca2+-gated Cl channel BEST2. In addition, intracellular Ca2+ stimulated a paxilline-sensitive and voltage-dependent, large-conductance K channel and a clotrimazole-sensitive, intermediate-conductance K channel, consistent with the detection of transcripts for KCNMA1 and KCNN4, respectively. Our results demonstrate that the ion transport mechanisms in human parotid glands are equivalent to those in the mouse, confirming that animal models provide valuable systems for testing therapies to prevent salivary gland dysfunction.

Cl-/HCO3- exchange is acetazolamide sensitive and activated by a muscarinic receptor-induced [Ca2+]i increase in salivary acinar cells

2004 ◽  
Vol 286 (2) ◽  
pp. G312-G320 ◽  
Author(s):  
Ha-Van Nguyen ◽  
Alan Stuart-Tilley ◽  
Seth L. Alper ◽  
James E. Melvin
Keyword(s):  
Salivary Gland ◽  
Carbonic Anhydrase ◽  
Muscarinic Receptor ◽  
Plasma Membranes ◽  
Acinar Cells ◽  
Parotid Glands ◽  
Atpase Inhibitor ◽  
Uptake Mechanism ◽  
Receptor Stimulation ◽  
Intracellular Ca

Large volumes of saliva are generated by transepithelial Cl- movement during parasympathetic muscarinic receptor stimulation. To gain further insight into a major Cl- uptake mechanism involved in this process, we have characterized the anion exchanger (AE) activity in mouse serous parotid and mucous sublingual salivary gland acinar cells. The AE activity in acinar cells was Na+ independent, electroneutral, and sensitive to the anion exchange inhibitor DIDS, properties consistent with the AE members of the SLC4A gene family. Localization studies using a specific antibody to the ubiquitously expressed AE2 isoform labeled acini in both parotid and sublingual glands. Western blot analysis detected an ∼170-kDa protein that was more highly expressed in the plasma membranes of sublingual than in parotid glands. Correspondingly, the DIDS-sensitive [Formula: see text] exchanger activity was significantly greater in sublingual acinar cells. The carbonic anhydrase antagonist acetazolamide markedly inhibited, whereas muscarinic receptor stimulation enhanced, the [Formula: see text] exchanger activity in acinar cells from both glands. Intracellular Ca2+ chelation prevented muscarinic receptor-induced upregulation of the AE, whereas raising the intracellular Ca2+ concentration with the Ca2+-ATPase inhibitor thapsigargin mimicked the effects of muscarinic receptor stimulation. In summary, carbonic anhydrase activity was essential for regulating [Formula: see text] exchange in salivary gland acinar cells. Moreover, muscarinic receptor stimulation enhanced AE activity through a Ca2+-dependent mechanism. Such forms of regulation may play important roles in modulating fluid and electrolyte secretion by salivary gland acinar cells.

scholarly journals Retrovirus-mediated Gene Transfer into Rat Salivary Gland Cells In Vitro and In Vivo

1997 ◽  
Vol 45 (11) ◽  
pp. 1533-1545 ◽  
Author(s):  
Tibor Barka ◽  
Hendrika M. van der Noen
Keyword(s):  
Enzyme Activity ◽  
Salivary Gland ◽  
Gene Transfer ◽  
Cell Line ◽  
Submandibular Gland ◽  
Acinar Cells ◽  
Retroviral Vector ◽  
Placental Alkaline Phosphatase

A retroviral vector DAP that encodes the human placental alkaline phosphatase (PLAP) and the neomycin-resistant gene was used to transduce the salivary gland-derived cell line A5 in vitro and acinar cells in rat submandibular gland in vivo. Expression of the transduced PLAP gene was established by histochemical staining for heat-resistant AP and by determination of enzyme activity. From the in vitro experiments, we concluded that the salivary gland-derived cell line A5 can be infected by the retroviral vector DAP. In the transduced cells the viral long terminal repeat (LTR) promoter was effective, and the cells expressed heat-stable PLAP which was localized mostly in the plasma membrane and could be released by treatment with bromelain or phosphatidyinositol-specific phospholipase C. A5-DAP cells secreted PLAP into the medium. Clones of A5-DAP cells expressed various levels of the enzyme. The level of enzyme activity in different clones was unrelated to growth rate. Retrograde ductal injection of the viral vector into the duct of the submandibular gland of rats resulted in integration and long-term expression of PLAP gene in acinar cells. Expression of PLAP was seen up to 25 days, the limit of the observation period. To facilitate integration of the viral DNA, cell division of acinar cells was induced by administration of the β-adrenergic agonist isoproterenol before administration of the virus. PLAP was secreted into submandibular saliva. The data support the notion that salivary glands are suitable targets for gene transfer in vivo by a retroviral vector. (J Histochem Cytochem 45:1533–1545, 1997)

scholarly journals α2A-Adrenergic Receptor Activation Decreases Parabrachial Nucleus Excitatory Drive onto BNST CRF Neurons and Reduces Their Activity In Vivo

2018 ◽  
Vol 39 (3) ◽  
pp. 472-484 ◽  
Author(s):  
Tracy L. Fetterly ◽  
Aakash Basu ◽  
Brett P. Nabit ◽  
Elias Awad ◽  
Kellie M. Williford ◽  
...  
Keyword(s):  
Adrenergic Receptor ◽  
Receptor Activation ◽  
Parabrachial Nucleus ◽  
Crf Neurons ◽  
Excitatory Drive

scholarly journals In Vivo β-Adrenergic Receptor Responsiveness: Ethnic Differences in the Relationship with Symptoms of Depression and Fatigue

2013 ◽  
Vol 21 (5) ◽  
pp. 843-850 ◽  
Author(s):  
Frank Euteneuer ◽  
Michael G. Ziegler ◽  
Paul J. Mills ◽  
Winfried Rief ◽  
Joel E. Dimsdale
Keyword(s):  
Ethnic Differences ◽  
Adrenergic Receptor ◽  
Symptoms Of Depression ◽  
The Relationship

scholarly journals Rat aquaporin-5 4.3-kb 5′-flanking region differentially regulates expression in salivary gland and lung in vivo

2008 ◽  
Vol 295 (1) ◽  
pp. C111-C120 ◽  
Author(s):  
Beiyun Zhou ◽  
David K. Ann ◽  
Per Flodby ◽  
Parviz Minoo ◽  
Janice M. Liebler ◽  
...  
Keyword(s):  
Salivary Gland ◽  
Salivary Glands ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Acinar Cells ◽  
Regulatory Elements ◽  
Egfp Expression ◽  
Type I ◽  
Aquaporin 5

We previously cloned a 4.3-kb genomic fragment encompassing 5′-flanking regulatory elements of rat aquaporin-5 ( Aqp5) that demonstrated preferential transcriptional activity in lung and salivary cells in vitro. To investigate the ability of Aqp5 regulatory elements to direct transgene expression in vivo, transgenic (TG) mice and rats were generated in which the 4.3-kb Aqp5 fragment directed the expression of enhanced green fluorescent protein (EGFP). RT-PCR revealed relative promoter specificity for the lung and salivary glands in TG mice. Immunofluorescence microscopy showed strong EGFP expression in salivary acinar cells but not in lung type I (AT1) cells, both known sites of endogenous AQP5 expression. Similar results were obtained in TG rats generated by lentiviral transgenesis. EGFP mRNA was detected in both salivary glands and lung. Robust EGFP fluorescence was observed in frozen sections of the rat salivary gland but not in the lung or other tested tissues. The percentage of EGFP-positive acinar cells was increased in parotid and submandibular glands of TG rats receiving a chronic injection of the β-adrenergic receptor agonist isoproterenol. EGFP-positive cells in the lung that were also reactive with the AT1-cell specific monoclonal antibody VIIIB2 were identified by flow cytometry. These findings demonstrate that the 4.3-kb Aqp5 promoter/enhancer directs strong cell-specific transgene expression in salivary gland and low-level AT1 cell-specific expression in the lung. While these Aqp5 regulatory elements should be useful for functional studies in salivary glands, additional upstream or intronic cis-active elements are likely required for robust expression in the lung.

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