Nitric oxide (NO) synthesized from L-arginine is a ubiquitous intracellular chemical messenger and involved in signal transduction diverse mammalian cells, including vascular endothelium neuronal tissues. The role of the NO-signaling pathway direct modulation cardiac function less well characterized. In this report, effects inhibitors NO synthase (NOS) were examined isolated neonatal adult rat ventricular myocytes exposed to either muscarinic or adrenergic agonists. Carbachol (10 microM)...

The mechanism by which soluble mediators of immune cell origin depress myocardial contractility, either globally as in systemic sepsis, or regionally areas inflammatory infiltrates, remains unclear. When freshly isolated ventricular myocytes from adult rat hearts were preincubated for at least 24 h medium conditioned endotoxin (LPS)-activated alveolar macrophages, their subsequent inotropic response to the beta-adrenergic agonist isoproterenol was reduced 225 +/- 19% 155 10% baseline...

Cellular constituents of heart muscle contain both constitutive and inducible nitric oxide (NO) signaling pathways that modulate the contractile properties cardiac myocytes. The identities NO synthase (iNOS) isoform(s) expressed in muscle, specific cell types expressing iNOS activity, remain poorly characterized. We amplified a 217-base pair cDNA by reverse transcriptase-polymerase chain reaction from primary cultures inflammatory cytokine-pretreated adult rat ventricular myocytes (ARVM) was...

Metabolic acidosis is associated with enhanced renal ammonia-genesis which regulated, in part, by glucocorticoids. The interaction between glucocorticoids and chronic metabolic on nitrogen utilization muscle protein metabolism unknown. In rats pair-fed gavage, we found that stunted growth caused a 43% increase urinary an 87% corticosterone. Net degradation incubated epitrochlearis muscles from chronically acidotic was stimulated at all concentrations of insulin 0 to 10(4) microU/ml. This...

Chronic renal failure (CRF) is associated with metabolic acidosis and abnormal muscle protein metabolism. As we have shown that by itself stimulates degradation a glucocorticoid-dependent mechanism, assessed the contribution of to changes in turnover CRF. A stable model uremia was achieved partially nephrectomized rats (plasma urea nitrogen, 100-120 mg/dl, blood bicarbonate less than 21 meq/liter). CRF excreted 22% more nitrogen pair-fed controls (P 0.005), so synthesis were measured...

Endothelin, a 21-amino acid vasoactive peptide, is among the most potent positively inotropic agents yet described in mammalian heart. Having demonstrated that endothelin's effect due, part, to an apparent sensitization of cardiac myofilaments intracellular calcium, we determined whether this could be due rise pH (pHi). In isolated adult rat ventricular cells loaded with H(+)-selective fluorescent probe BCECF, 100 pM endothelin increased contractile amplitude 190 +/- 26% baseline and pHi by...

Cardiac myocytes express both constitutive and cytokine-inducible nitric oxide syntheses (NOS). NO its congeners have been implicated in the regulation of cardiac contractile function. To determine whether could affect myocardial energetics, 31P NMR spectroscopy was used to evaluate high-energy phosphate metabolism isolated rat hearts perfused with donor S-nitrosoacetylcysteine (SNAC). All were exposed an initial high Ca2+ (3.5 mM) challenge followed by a recovery period, then, either...

It has long been assumed that the primary influences regulating cardiac contractility are extent of mechanical loading muscle fibers and activity autonomic nervous system. However, vasoactive peptide endothelin, initially found in vascular endothelium, is among most potent positively inotropic agents yet described mammalian myocardium. In isolated adult rat ventricular cells, endothelin's action was slow onset but very lasting with an EC50 50 pM approximates reported KD for its receptor...

Elevated plasma levels of factors with cardiac glycoside-like activity have been implicated in the response to volume expansion animals and pathogenesis certain human diseases.We recently described four fractions (IR1, EI1, E12, El3) from normal that inhibit NaK-ATPase, displace ouabain enzyme, exhibit digoxin-like immunoreactivity (Kelly, R.

Despite large gains in the medical and surgical treatment of angina pectoris past two decades, many patients are refractory to conventional therapy unsuitable for a first or, more commonly, repeat coronary revascularization procedure. We evaluated efficacy perhexiline maleate, drug with an antianginal mechanism action humans that is as yet unknown, by using randomized double-blind placebo-controlled crossover design 17 who continued receive maximal therapy, typically including nitrates,...

We have identified a previously undescribed intrinsic cardiac adrenergic (ICA) cell type in rodent and human heart. Northern Western blot analyses demonstrated that ICA isolates contain mRNA protein of enzymes involved catecholamine biosynthesis. Radioenzymatic assays also revealed the profile adult rat differed from sympathetic neurons. Unlike neuronal cells, isolated cells abundant clear vesicles on electron microscopy. Endogenous norepinephrine epinephrine constitutively released by vitro...

One of the trophic factors that has been implicated in initiating or facilitating growth response to increased mechanical stress several tissues and cell types is basic fibroblast factor (bFGF; FGF-2). Although mammalian cardiac muscle cells express bFGF, it not known whether plays a role mediating adaptation load, nor how release cytosolic 18-kD isoform bFGF would be regulated stress. To test hypothesis activity induces transient alterations sarcolemmal permeability allow released...

Branched-chain amino acid (BCAA) metabolism is frequently abnormal in pathological conditions accompanied by chronic metabolic acidosis. To study how acidosis affects BCAA muscle, rats were gavage fed a 14% protein diet with or without 4 mmol NH4Cl X 100 g body wt-1 day-1. Epitrochlearis muscles incubated L-[1-14C]-valine and L-[1-14C]leucine, rates of decarboxylation, net transamination, incorporation into muscle measured. Plasma levels lower (P less than 0.05) acidotic rats. Rates valine...

Although reciprocal intercellular signaling may occur between endocardial or microvascular endothelium and cardiac myocytes, suitable in vitro models have not been well characterized. In this report, we describe the isolation primary culture of endothelial cells (CMEC) from both adult rat human ventricular tissue. Differential uptake fluorescently labeled acetylated low-density lipoprotein (Ac-LDL) indicated that isolates CMEC were quite homogeneous, unlike tissue, which required cell...

We examined the role of endogenous NO in autonomic regulation atrioventricular (AV) nodal function by studying spontaneous action potentials (SAPs) and L-type Ca2+ current (ICa-L) isolated single AV cells from adult rabbit hearts. Both perforated membrane-ruptured patch-clamp techniques whole-cell configuration were used under conditions known to alter production. Three donors, 3-morpholinosydnonimine (SIN-1, 0.1 mmol/L), S-nitroso-acetylcysteine (0.1 sodium nitroprusside suppressed...

To model with greater fidelity the electromechanical function of freshly isolated heart muscle cells in primary culture, we describe a technique for continual electrical stimulation adult myocytes at physiological frequencies several days. A reusable plastic cover was constructed to fit standard, disposable 175-cm2 tissue culture flasks and hold parallel graphite electrodes along long axis each flask, which treated uniform electric field that resulted capture efficiency ventricular 75–80%....

Adult rat ventricular myocytes undergo a well-documented sequence of phenotypic changes during adaptation to primary culture. However, we observed that coculture with specific subset nonmyocyte cardiac cells could slow and even reverse the process adaptation. These were isolated identified by immunohistochemical ultrastructural criteria as being epicardial mesothelial origin. When added long-term cultures adult myocytes, appeared induce myofibrillar arrays more organized than those seen in...

We studied primary short-term cultures of adult rat ventricular myocytes in defined medium to determine whether phenotype and electromechanical function are maintained rod-shaped, quiescent cells. Although > 80% the retained their rod-shaped vivo morphology for up 72 h, contractile as measured by cell edge motion declined 30-50% from 6 24 paralleling a 68% shortening action potential duration. From contractility remained unchanged. Ca2+ channel current density increased 55% after 24-48 h...

There are important phenotypic differences between endothelial cells of large vessels and the microvasculature among microvascular isolated from different tissues organs. In contrast to most macrovascular cells, we demonstrate that cultured cardiac (CMEC) have no detectable constitutive NO synthase (NOS) activity but a robust increase in NOS response specific inflammatory cytokines. To determine identity inducible (iNOS) isoform(s) induced by cytokines, used reverse-transcription polymerase...

Much of the evidence for a physiologically important endogenous inhibitor sodium pump has been either contradictory or indirect.We have identified three discrete fractions in desalted deproteinized plasma from normal humans that resemble digitalis glycosides they: 1) are low molecular weight; 2) resistant to acid and enzymatic proteolysis; 3) inhibit NaK-ATPase activity; 4) Na+ activity human erythrocytes; 5 ) displace [3H]ouabain bound enzyme; 6 cross-react with highaffinity polyclonal...

Negative nitrogen balance and increased oxygen consumption after thermal injury in humans experimental animals is related to the extent of burn. To determine whether defective muscle metabolism restricted region injury, we studied protein glucose forelimb muscles rats 48 h a scalding their hindquarters. This degradation (PD) from 140 +/- 5 225 nmol tyrosine/g per h, but did not alter synthesis. Muscle lactate release was greater than 70%, even though plasma catecholamines cyclic AMP were...

Aminoquinolines (AQ) and substituted aminoquinolines (s-AQ) interact with electrochemically monitored supported dioleoyl phosphatidylcholine (DOPC) monolayers immobilised artificial membranes (IAM) on HPLC column. The electrochemical sensor records adsorption/partition of the compound into layer as well specific interactions due to location in layer. HPLC-IAM technology measures partition coefficient between solution phospholipid including interaction positive molecular charge polar heads....