Publications by authors named "Howard Lippton"

Acid-sensing ion channel-1 (ASIC-1) is a proton-gated ion channel implicated in nociception and neuronal death during ischemia. Recently the first crystal structure of a chicken ASIC was obtained. Expanding upon this work, homology models of the human ASICs were constructed and evaluated.

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Recent reports have demonstrated a potential role of tissue prorenin in the pathogenesis of cardiovascular and renal damage. This study was designed to examine the role of prorenin in the pathogenesis of target organ damage in spontaneously hypertensive rats (SHRs), the best naturally occurring experimental model of essential hypertension. To this end, we studied 20-wk-old male SHRs receiving a normal diet and 8-wk-old male SHRs given food with 8% NaCl.

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The present study was designed to investigate the effects of rat intermedin/adrenomedullin2 (rIMD), an agonist for calcitonin-like calcitonin receptors (CRLR), on the isolated rat pulmonary arterial rings (PA). When PA were precontracted with 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F2alpha (U-46619), rIMD (10(-11) to 10(-6)M) induced concentration-dependent relaxation. The pulmonary vasorelaxant response (PVR) to rIMD in PA were completely inhibited by endothelium removal, NG-nitro-L-arginine-methyl-ester (L-NAME), l-N5-(1-iminoethyl)-ornithine hydrochloride (l-NIO) or 1H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ).

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We compared the effects of genistein with its structural derivatives daidzein and equol on excitation of pulmonary artery and vein. The concentration of genistein necessary to inhibit contractions evoked by U46619 (1nM-100 microM) ranged from 10 to 100 microM. Genistein (55 microM) reduced KCl-responses by approximately 50% and essentially abolished those evoked by U46619.

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Recent studies have been focused on the protective role of ischemic preconditioning against ischemia-reperfusion injury of the lung occurring following cardiopulmonary by-pass surgery and lung or heart transplantation. The present study was undertaken to investigate the role of adenosine in ischemic preconditioning in the isolated buffer-perfused rat lung. Since the pulmonary perfusion flow rate and left atrial pressure were constant, changes in pulmonary arterial pressure directly reflect changes in pulmonary vascular resistance.

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Ischemic preconditioning (IP) may protect the lung from ischemia-reperfusion (I/R) injury following cardiopulmonary by-pass and lung or heart transplantation. The present study was undertaken to investigate the role of ATP-dependent potassium channels (K(ATP)) in IP in the isolated buffer-perfused rat lung (IBPR) under conditions of elevated pulmonary vasoconstrictor tone (PVT). Since pulmonary arterial perfusion flow and left atrial pressure were constant, changes in pulmonary arterial pressure (PAP) directly reflect changes in pulmonary vascular resistance (PVR).

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The present study was undertaken to investigate the effects of intravenous (i.v.) administration of rat hemopressin (rHP), 30-1000 microg/kg, on systemic arterial pressure (SAP), cardiac output (CO) and systemic vascular resistance (SVR) in the anesthetized rat.

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Intermedin/adrenomedullin-2 (IMD/AM2) is a 47 amino acid peptide formed by enzymatic degradation of preprointermedin. The present study was undertaken to investigate the effects of rat IMD (rIMD) in the isolated buffer perfused rat lung (IBPR) under resting conditions and under conditions of elevated pulmonary vasoconstrictor tone (PVT). Under resting conditions in the IBPR, rIMD had little or no activity.

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