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Full-Text Articles in Life Sciences

The Evolving Role Of Lipid Rafts And Caveolae In G Protein-Coupled Receptor Signaling: Implications For Molecular Pharmacology, Rennolds S. Ostrom, Paul A. Insel Jan 2004

The Evolving Role Of Lipid Rafts And Caveolae In G Protein-Coupled Receptor Signaling: Implications For Molecular Pharmacology, Rennolds S. Ostrom, Paul A. Insel

Pharmacy Faculty Articles and Research

The many components of G-protein-coupled receptor (GPCR) signal transduction provide cells with numerous combinations with which to customize their responses to hormones, neurotransmitters, and pharmacologic agonists. GPCRs function as guanine nucleotide exchange factors for heterotrimeric (α, β, γ) G proteins, thereby promoting exchange of GTP for GDP and, in turn, the activation of ‘downstream’ signaling components. Recent data indicate that individual cells express mRNA for perhaps over 100 different GPCRs (out of a total of nearly a thousand GPCR genes), several different combinations of G-protein subunits, multiple regulators of G-protein signaling proteins (which function as GTPase activating proteins), and various …


Angiotensin Ii Enhances Adenylyl Cyclase Signaling Via Ca2+/Calmodulin. Gq-Gs Cross-Talk Regulates Collagen Production In Cardiac Fibroblasts, Rennolds S. Ostrom, Jennifer E. Naugle, Miki Hase, Caroline Gregorian, James S. Swaney, Paul A. Insel, Laurence L. Brunton, J. Gary Meszaros Jan 2003

Angiotensin Ii Enhances Adenylyl Cyclase Signaling Via Ca2+/Calmodulin. Gq-Gs Cross-Talk Regulates Collagen Production In Cardiac Fibroblasts, Rennolds S. Ostrom, Jennifer E. Naugle, Miki Hase, Caroline Gregorian, James S. Swaney, Paul A. Insel, Laurence L. Brunton, J. Gary Meszaros

Pharmacy Faculty Articles and Research

Cardiac fibroblasts regulate formation of extracellular matrix in the heart, playing key roles in cardiac remodeling and hypertrophy. In this study, we sought to characterize cross-talk between Gq and Gs signaling pathways and its impact on modulating collagen synthesis by cardiac fibroblasts. Angiotensin II (ANG II) activates cell proliferation and collagen synthesis but also potentiates cyclic AMP (cAMP) production stimulated by β-adrenergic receptors (β-AR). The potentiation of β-AR-stimulated cAMP production by ANG II is reduced by phospholipase C inhibition and enhanced by overexpression of Gq. Ionomycin and thapsigargin increased intracellular Ca2+ levels and potentiated isoproterenol- and forskolin-stimulated cAMP production, whereas …


Hypertonic Stress Co-Stimulates T Cell Il-2 Expression Through A Feedback Mechanism Involving Atp Release And P2 Receptor Activation Of P38 Map Kinase, William H. Loomis, Sachiko Namiki, Rennolds S. Ostrom, Paul A. Insel, Wolfgang G. Junger Jan 2003

Hypertonic Stress Co-Stimulates T Cell Il-2 Expression Through A Feedback Mechanism Involving Atp Release And P2 Receptor Activation Of P38 Map Kinase, William H. Loomis, Sachiko Namiki, Rennolds S. Ostrom, Paul A. Insel, Wolfgang G. Junger

Pharmacy Faculty Articles and Research

Hypertonic stress (HS) can alter the function of mammalian cells. We have reported that HS enhances differentiated responses of T cells by increasing their ability to produce interleukin (IL)-2, a finding of clinical interest because hypertonic infusions may modulate immune function in patients. HS shrinks cells and mechanically deforms membranes, which results in ATP release from many cell types. Here we investigate if ATP release is an underlying mechanism through which HS augments T cell function. We found that mechanical stress and HS induced rapid ATP release from Jurkat T cells. HS and exogenous ATP mobilized intracellular Ca2+, activated p38 …


Receptor Number And Caveolar Co-Localization Determine Receptor Coupling Efficiency To Adenylyl Cyclase, Rennolds S. Ostrom, Caroline Gregorian, Ryan M. Drenan, Yang Xiang, John W. Regan, Paul A. Insel Jan 2001

Receptor Number And Caveolar Co-Localization Determine Receptor Coupling Efficiency To Adenylyl Cyclase, Rennolds S. Ostrom, Caroline Gregorian, Ryan M. Drenan, Yang Xiang, John W. Regan, Paul A. Insel

Pharmacy Faculty Articles and Research

Recent evidence suggests that many signaling molecules localize in microdomains of the plasma membrane, particularly caveolae. In this study, overexpression of adenylyl cyclase was used as a functional probe of G protein-coupled receptor (GPCR) compartmentation. We found that three endogenous receptors in neonatal rat cardiomyocytes couple with different levels of efficiency to the activation of adenylyl cyclase type 6 (AC6), which localizes to caveolin-rich membrane fractions. Overexpression of AC6 enhanced the maximal cAMP response to β1-adrenergic receptor (β1AR)-selective activation 3.7-fold, to β2AR-selective activation only 1.6-fold and to prostaglandin E2 (PGE2) not at all. Therefore, the rank order of efficacy in …


Cellular Release Of And Response To Atp As Key Determinants Of The Set-Point Of Signal Transduction Pathways, Rennolds S. Ostrom, Caroline Gregorian, Paul A. Insel Jan 2000

Cellular Release Of And Response To Atp As Key Determinants Of The Set-Point Of Signal Transduction Pathways, Rennolds S. Ostrom, Caroline Gregorian, Paul A. Insel

Pharmacy Faculty Articles and Research

The determinants of “basal” activity of signaling pathways regulating cellular responses are poorly defined. One possibility is that cells release factors to establish the set-point of such pathways. Here we show that treatment of Madin-Darby canine kidney cells with the nucleotidase apyrase decreases basal arachidonic acid release and cAMP production 30–40% and that inhibitors of P2Y receptor action also affect basal and forskolin-stimulated cAMP accumulation. Changing medium prominently increases extracellular levels of ATP in Madin-Darby canine kidney, COS-7, and HEK-293 cells. Mechanical stimulation of ATP release likely occurs in virtually every experimental protocol with cultured cells, implicating such release and …


Effect Of Actinomycin D And Cycloheximide On Ischemic Preconditioning-Induced Delayed Cardioprotective Effect In Rats, Devinder Singh, Ajay Sharma, Manjeet Singh Jan 2000

Effect Of Actinomycin D And Cycloheximide On Ischemic Preconditioning-Induced Delayed Cardioprotective Effect In Rats, Devinder Singh, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The present study was designed to investigate the effect of actinomycin D, a transcription inhibitor, and cycloheximide, a translation inhibitor, on the delayed cardioprotective effect of ischemic preconditioning. Left thoracotomy was performed in anaesthetized rats at 4th/5th intercostal space and polypropylene suture (5-0) was employed to occlude left common coronary artery. Ischemic preconditioning was produced by four episodes of 5 min of coronary artery occlusion followed by 5 min of reperfusion and thoracic cavity was sutured. Left thoracotomy was performed again after 24 hr of ischemic preconditioning and left coronary artery was occluded for 30 min followed by reperfusion for …


Role Of KAtp Channels In Reduced Antinociceptive Effect Of Morphine In Streptozotocin-Induced Diabetic Mice, Vivek Sood, Ajay Sharma, Manjeet Singh Jan 2000

Role Of KAtp Channels In Reduced Antinociceptive Effect Of Morphine In Streptozotocin-Induced Diabetic Mice, Vivek Sood, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The nociceptive effect was measured using withdrawal latency in tail flick test in mice rendered diabetic by administering streptozotocin (200 mg/kg, i.p.). The antinociceptive effect of morphine (4 and 8 mg/kg, s.c.) and cromakalim, a KATP channel opener, (0.3, 1 and 2 micrograms, i.c.v.) was significantly reduced in diabetic mice. Moreover, co-administration of cromakalim(0.3 microgram) did not alter the reduced antinociceptive effect of morphine(4 mg/kg) in diabetic mice. Spleenectomy in diabetic mice restored the decrease in antinociceptive effect of morphine and cromakalim. Multiple dose treatment with insulin to maintain euglycaemia for 3 days in diabetic mice prevented the decrease in …


Inhibition Of Cpla2-Mediated Arachidonic Acid Release By Cyclic Amp Defines A Negative Feedback Loop For P2y-Receptor Activation In Mdck-D1 Cells, Mingzhao Xing, Steven Post, Rennolds S. Ostrom, Michael Samardzija, Paul A. Insel Jan 1999

Inhibition Of Cpla2-Mediated Arachidonic Acid Release By Cyclic Amp Defines A Negative Feedback Loop For P2y-Receptor Activation In Mdck-D1 Cells, Mingzhao Xing, Steven Post, Rennolds S. Ostrom, Michael Samardzija, Paul A. Insel

Pharmacy Faculty Articles and Research

In Madin-Darby canine kidney D1cells extracellular nucleotides activate P2Y receptors that couple to several signal transduction pathways, including stimulation of multiple phospholipases and adenylyl cyclase. For one class of P2Y receptors, P2Y2 receptors, this stimulation of adenylyl cyclase and increase in cAMP occurs via the conversion of phospholipase A2 (PLA2)-generated arachidonic acid (AA) to prostaglandins (e.g. PGE2). These prostaglandins then stimulate adenylyl cyclase activity, presumably via activation of prostanoid receptors. In the current study we show that agents that increase cellular cAMP levels (including PGE2, forskolin, and the β-adrenergic agonist isoproterenol) can inhibit P2Y receptor-promoted AA release. The protein kinase …


Outpatient Administration Of Paclitaxel, Siu Fun Wong Jan 1994

Outpatient Administration Of Paclitaxel, Siu Fun Wong

Pharmacy Faculty Articles and Research

Paclitaxel (Taxol®, Bristol-Meyers Squibb), anti neoplastic agent made from the bark of the Pacific yew tree, is undoubtedly one of the most exciting agents to be evaluated over the past decade. Paclitaxel has demonstrated significant promise against ovarian and metastatic breast cancer, and appears to be the most effective single agent to date for non-small-cell lung cancer in trials conducted by Eastern Cooperative Oncology Group (ECOG).