scholarly journals Different intracellular polyamine concentrations underlie the difference in the inward rectifier K+currents in atria and ventricles of the guinea-pig heart

2005 ◽  
Vol 563 (3) ◽  
pp. 713-724 ◽  
Author(s):  
Ding-Hong Yan ◽  
Kazuhiro Nishimura ◽  
Kaori Yoshida ◽  
Kei Nakahira ◽  
Tsuguhisa Ehara ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Inward Rectifier ◽  
Guinea Pig Heart ◽  
The Difference ◽  
K Currents

Sevoflurane and Isoflurane Protect the Reperfused Guinea Pig Heart by Reducing Postischemic Adhesion of Polymorphonuclear Neutrophils 

1999 ◽  
Vol 91 (2) ◽  
pp. 521-530 ◽  
Author(s):  
Bernhard Heindl ◽  
Florian M. Reichle ◽  
Stefan Zahler ◽  
Peter F. Conzen ◽  
Bernhard F. Becker
Keyword(s):  
Guinea Pig ◽  
Cardiac Function ◽  
Minimum Alveolar Concentration ◽  
Volatile Anesthetics ◽  
Underlying Mechanism ◽  
Polymorphonuclear Neutrophils ◽  
Guinea Pig Heart ◽  
Cd11b Expression ◽  
Heart Work ◽  
The Difference

Background Polymorphonuclear neutrophils (PMNs) contribute to reperfusion injury. Because volatile anesthetics can reduce PMN adhesion in the reperfused, nonworking heart, the authors analyzed whether this action of volatile anesthetics affects cardiac performance after ischemia and reperfusion and further clarified the underlying mechanism. Methods Isolated guinea pig hearts perfused with crystalloid buffer and performing pressure-volume work were used. Hearts were subjected to 15 min global ischemia and 20 min reperfusion. In the intervention groups an intracoronary bolus of 3 x 10(6) PMNs was applied in the second min of reperfusion, either in the absence or presence of 0.5 or 1 minimum alveolar concentration sevoflurane or isoflurane. The number of sequestered PMNs was calculated from the difference between coronary input and output (coronary effluent) of PMNs. Performance of external heart work, determined pre- and postischemically, served as criterion for recovery of myocardial function. Additionally, the expression of the integrin CD11b on the cell surface of PMN was measured before and after coronary passage. Results Injection of PMN in the reperfusion phase, but not under nonischemic conditions, reduced recovery of external heart work significantly (from 55+/-7% to 19+/-11%). Addition of sevoflurane or isoflurane in concentrations of 0.5 and 1 minimum alveolar concentration to the perfusate reduced postischemic PMN adhesion from 36+/-8% to basal values (20+/-7%) and prevented decline of cardiac function. CD11b expression on PMNs increased significantly during postischemic coronary passage under control conditions. Again, both anesthetics in both concentrations inhibited that activation. Conclusions Volatile anesthetics reduce PMN adhesion in the reperfused coronary system and thereby preserve cardiac function. Reduced expression of the adhesion molecule CD11b on PMNs in the presence of sevoflurane or isoflurane is, at least in part, responsible for the cardioprotective effect.

Monophasic action potentials during induced hypothermia in hedgehog and guinea pig hearts

1987 ◽  
Vol 253 (5) ◽  
pp. H1083-H1088 ◽  
Author(s):  
G. Duker ◽  
P. O. Sjoquist ◽  
B. W. Johansson
Keyword(s):  
Body Temperature ◽  
Guinea Pig ◽  
Cardiac Electrophysiology ◽  
Simultaneous Recording ◽  
Monophasic Action Potential ◽  
Guinea Pig Heart ◽  
Normal Body Temperature ◽  
Normal Body ◽  
Potential Map ◽  
The Difference

To evaluate mechanisms behind the difference in susceptibility to ventricular fibrillation (VF) between the guinea pig and hedgehog heart, the cardiac electrophysiology of the two species was studied at normal body temperature and at different hypothermic levels by simultaneous recording of the monophasic action potential (MAP) and the external electrocardiogram (ECG). At normal body temperature, the duration of the ventricular MAP was significantly shorter in the hedgehog (93 +/- 8.1 ms) than in the guinea pig (138 +/- 2.6 ms). There was a distinct plateau phase in the guinea pig, whereas no such phase could be detected in the hedgehog. During hypothermia, a similar increase in MAP duration at full repolarization was noticed for both species. However, the prolongation of the MAP at lower repolarization levels was much less in the hedgehog. Besides, hypothermia-induced slow conduction and dispersion of ventricular repolarization was much more apparent in the guinea pig heart compared with the hedgehog heart. These differences may be important factors in the resistance to VF in the hedgehog, at normal body temperature and during hypothermia.

scholarly journals Plasmenylcholine (1-O-alk-1′-enyl-2-acyl-sn-glycero-3-phosphocholine) biosynthesis in guinea-pig heart and liver: cholinephosphotransferase is a bifunctional enzyme for the synthesis of phosphatidylcholine and plasmenylcholine

1994 ◽  
Vol 301 (1) ◽  
pp. 131-137 ◽  
Author(s):  
Y F Xu ◽  
K O ◽  
P C Choy
Keyword(s):  
Guinea Pig ◽  
Significant Proportion ◽  
Specific Radioactivity ◽  
Minor Component ◽  
Guinea Pig Heart ◽  
Chase Period ◽  
Choline Phosphoglycerides ◽  
The Difference ◽  
A Minor ◽  
Guinea Pig Liver

Plasmenylcholine is present in significant proportion (32% of choline phosphoglycerides) in the guinea-pig heart but exists as a minor component (3% of choline phosphoglycerides) in the guinea-pig liver. In this study, the biosynthesis of plasmenylcholine in these two organs was examined. The organs were perfused with labelled choline for 15 min and chased with unlabelled choline for up to 7 h. The labelling of phosphatidylcholine was 6-fold higher than that of plasmenylcholine in the heart and about 60-fold higher in the liver. However, the same labelling ratio was maintained throughout the chase period in both organs. Alterations in the specific radioactivity of CDP-choline caused corresponding changes in the labelling of phosphatidylcholine and plasmenylcholine. Our results suggest that in guinea-pig heart and liver, CDP-choline is the immediate precursor of biosynthesis of phosphatidylcholine and plasmenylcholine. The biochemical cause for the difference in their rates of formation between the two organs was explored. The enzyme activities for the formation of both choline phosphoglycerides were determined. The two reactions share the same characteristics, and 1,2-diacylglycerol and 1-alk-1′-enyl-2-acylglcerol were found to be mutually inhibitory in a competitive fashion. The pool sizes of 1,2-diacylglycerol and 1-alk-1′-enyl-2-acylglycerol were determined, and their ratios were found to be 42 in the heart and 422 in the liver. We conclude that cholinephosphotransferase catalyses the formation of both phosphatidylcholine and plasmenylcholine in the guinea-pig tissues and the rate of plasmenylcholine biosynthesis is dependent on the availability of 1-alk-1′-enyl-2-acylglycerol. Plasmenylcholine biosynthesis is also subjected to modulation by the 1,2-diacylglycerol content of the tissue.

Osmosensitive properties of rapid and slow delayed rectifier K+ currents in guinea-pig heart cells

2003 ◽  
Vol 30 (9) ◽  
pp. 616-622 ◽  
Author(s):  
Toshitsugu Ogura ◽  
Hiroyuki Matsuda ◽  
Toshishige Shibamoto ◽  
Sunao Imanishi
Keyword(s):  
Guinea Pig ◽  
Delayed Rectifier ◽  
Heart Cells ◽  
Guinea Pig Heart ◽  
K Currents

Mitochondrial Oxidation of p-N, N-Dimethylamino-β-Phenethylamine (DAPA)

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.

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

2002 ◽  
Vol 80 (6) ◽  
pp. 578-587 ◽  
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 (10–9 to 10–5 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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