Effect of L-propionyl carnitine on reoxygenation arrhythmias in the isolated guinea pig heart

1975 ◽

Vol 33 ◽

pp. 458-459

Author(s):

W. Allen Shannon ◽

Hannah L. Wasserkrug ◽

andArnold M. Seligman

Keyword(s):

Guinea Pig ◽

Oxidase Activity ◽

Amine Oxidase ◽

Histochemical Demonstration ◽

Guinea Pig Heart ◽

Pig Kidney ◽

Cytoplasmic Vacuoles ◽

Liver And Kidney ◽

Mitochondrial Oxidation ◽

Amine Oxidase Activity

The synthesis of a new substrate, p-N,N-dimethylamino-β-phenethylamine (DAPA)3 (Fig. 1) (1,2), and the testing of it as a possible substrate for tissue amine oxidase activity have resulted in the ultracytochemical localization of enzyme oxidase activity referred to as DAPA oxidase (DAPAO). DAPA was designed with the goal of providing an amine that would yield on oxidation a stronger reducing aldehyde than does tryptamine in the histochemical demonstration of monoamine oxidase (MAO) with tetrazolium salts.Ultracytochemical preparations of guinea pig heart, liver and kidney and rat heart and liver were studied. Guinea pig kidney, known to exhibit high levels of MAO, appeared the most reactive of the tissues studied. DAPAO reaction product appears primarily in mitochondrial outer compartments and cristae (Figs. 2-4). Reaction product is also localized in endoplasmic reticulum, cytoplasmic vacuoles and nuclear envelopes (Figs. 2 and 3) and in the sarcoplasmic reticulum of heart.

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Electrophysiological and Antiarrhythmic Effects of UK 52046-27 during Ischaemia and Reperfusion in the Guinea Pig Heart

Clinical Science ◽

10.1042/cs074016p ◽

1988 ◽

Vol 74 (s18) ◽

pp. 16P-16P

Author(s):

N A Flores ◽

D J Sheridan

Keyword(s):

Guinea Pig ◽

Guinea Pig Heart ◽

Ischaemia And Reperfusion ◽

Antiarrhythmic Effects

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Functional and autoradiographic characterization of dopamine D2-like receptors in the guinea pig heart

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y02-081 ◽

2002 ◽

Vol 80 (6) ◽

pp. 578-587 ◽

Cited By ~ 14

Author(s):

María de Jesús Gómez ◽

Guy Rousseau ◽

Réginald Nadeau ◽

Roberto Berra ◽

Gonzalo Flores ◽

...

Keyword(s):

Guinea Pig ◽

Western Blot ◽

Dopamine Receptors ◽

Negative Inotropic Effect ◽

Cyclase Activity ◽

Inotropic Effect ◽

Receptor Subtypes ◽

Guinea Pig Heart ◽

Additional Information ◽

The Right

Dopamine receptors include the D1- (D1 and D5 subtypes) and D2-like (D2, D3, and D4 subtypes) families. D1-like receptors are positively and D2-like receptors negatively coupled to the adenylyl cyclase. Dopamine D2-like (D4 subtype) receptors have been identified in human and rat hearts. However the presence of D2 and D3 receptor subtypes is unclear. Furthermore, their role in cardiac functions is unknown. By autoradiographic studies of guinea pig hearts, we identified D3 and D4 receptors, using the selective radioligands [3H]-7-OH-DPAT and [3H]emonapride (YM-09151-2 plus raclopride). Western blot analysis confirmed D3 and D4 receptors in the right and left ventricle of the same species. Selective agonists of D3 and D4 receptors (±)-7-OH-DPAT and PD 168 077 (109 to 105 M, respectively) induced a significant negative chronotropic and inotropic effect in the isolated guinea pig heart preparation. Negative inotropic effect induced by PD 168 077 was associated with an inhibition in cyclase activity. No changes in cyclase activity were found with (±)-7-OH-DPAT. The aim of this study is to support the presence of D3 and D4 receptors in the heart. Although our results suggest that D3 and D4 receptors are functionally active in the heart, we need additional information with an antagonist and an agonist of improved potency and selectivity to understand the respective roles of D3 and D4 receptors in the cardiac functions.Key words: Dopamine receptors (D2, D3, D4 subtypes), autoradiography, Western blot, cAMP, heart.

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The intraçellular and intramitochondrial distribution of short-chain acyl-CoA synthetases in guinea-pig heart

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism ◽

10.1016/0005-2760(71)90115-9 ◽

1971 ◽

Vol 231 (3) ◽

pp. 479-486 ◽

Cited By ~ 23

Author(s):

H.R. Scholte ◽

E.M. Wit-Peeters ◽

J.C. Bakker

Keyword(s):

Guinea Pig ◽

Short Chain ◽

Guinea Pig Heart ◽

Chain Acyl

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Involvement of A pertussis Toxin Sensitive G-Protein in the Inhibition of Inwardly Rectifying K+Currents by Platelet-Activating Factor in Guinea-Pig Atrial Cardiomyocytes

Mediators of Inflammation ◽

10.1155/s0962935194000086 ◽

1994 ◽

Vol 3 (1) ◽

pp. 45-51

Author(s):

M. Gollasch ◽

T. Kleppisch ◽

D. Krautwurst ◽

D. Lewinsohn ◽

J. Hescheler

Keyword(s):

Cyclic Amp ◽

Guinea Pig ◽

G Protein ◽

Pertussis Toxin ◽

Platelet Activating Factor ◽

Resting Membrane Potential ◽

Patch Clamp Technique ◽

Guinea Pig Heart ◽

Ventricular Cells ◽

Inwardly Rectifying

Platelet-activating factor (PAF) inhibits single inwardly rectifying K+channels in guinea-pig ventricular cells. There is currently little information as to the mechanism by which these channels are modulated. The effect of PAF on quasi steady-state inwardly rectifying K+currents (presumably of the IK1type) of auricular, atrial and ventricular cardiomyocytes from guinea-pig were studied. Applying the patch-clamp technique in the whole-cell configuration, PAF (10 nM) reduced the K+currents in all three cell types. The inhibitory effect of PAF occurred within seconds and was reversible upon wash-out. It was almost completely abolished by the PAF receptor antagonist BN 50730. Intracellular infusion of atrial cells with guanine 5′-(β-thio)diphosphate (GDPS) or pretreatment of cells with pertussis toxin abolished the PAF dependent reduction of the currents. Neither extracellularly applied isoproterenol nor intracellularly applied adenosine 3′,5′-cyclic monophosphate (cyclic AMP) attenuated the PAF effect. In multicellular preparations of auricles, PAF (10 nM) induced arrhythmias. The arrhythmogenic activity was also reduced by BN 50730. The data indicate that activated PAF receptors inhibit inwardly rectifying K+currents via a pertussis toxin sensitive G-protein without involvement of a cyclic AMP-dependent step. Since IK1is a major component in stabilizing the resting membrane potential, the observed inhibition of this type of channel could play an important role in PAF dependent arrhythmogenesis in guinea-pig heart.

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Evidence for the regulation of guinea-pig heart microsomal phosphatidylcholine-hydrolysing phospholipase A1 by guanosine 5′-[γ-thio]triphosphate

Biochemical Journal ◽

10.1042/bj2880965 ◽

1992 ◽

Vol 288 (3) ◽

pp. 965-968 ◽

Cited By ~ 3

Author(s):

K Badiani ◽

X Lu ◽

G Arthur

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Guinea Pig ◽

Molecular Species ◽

Inhibitory Effect ◽

Phospholipase A1 ◽

Guinea Pig Heart ◽

Substrate Specificities ◽

Rate Of Hydrolysis ◽

Hydrolysis Of

We have recently characterized lysophospholipase A2 activities in guinea-pig heart microsomes and postulated that these enzymes act sequentially with phospholipases A1 to release fatty acids selectively from phosphatidylcholine (PC) and phosphatidylethanolamine, thus providing an alternative route to the phospholipase A2 mode of release. In a further investigation of the postulated pathway, we have characterized the PC-hydrolysing phospholipase A1 in guinea-pig heart microsomes. Our results show that the enzyme may have a preference for substrates with C16:0 over C18:0 at the sn-1 position. In addition, although the enzyme cleaves the sn-1 fatty acid, the rate of hydrolysis of PC substrates with C16:0 at the sn-1 position was influenced by the nature of the fatty acid at the sn-2 position. The order of decreasing preference was C18:2 > C20:4 = C18:1 > C16:0. The hydrolyses of the molecular species were differentially affected by heating at 60 degrees C. An investigation into the effect of nucleotides on the activity of the enzyme showed that guanosine 5′-[gamma-thio]triphosphate (GTP[S]) inhibited the hydrolysis of PC by phospholipase A1 activity, whereas GTP, guanosine 5′-[beta-thio]diphosphate (GDP[S]), GDP, ATP and adenosine 5′-[gamma-thio]triphosphate (ATP[S]) did not affect the activity. The inhibitory effect of GTP[S] on phospholipase A1 activity was blocked by preincubation with GDP[S]. A differential effect of GTP[S] on the hydrolysis of different molecular species was also observed. Taken together, the results of this study suggest the presence of more than one phospholipase A1 in the microsomes with different substrate specificities, which act sequentially with lysophospholipase A2 to release linoleic or arachidonic acid selectively from PC under resting conditions. Upon stimulation and activation of the G-protein, the release of fatty acids would be inhibited.

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