Cardiac resistance against acute ischemia/reperfusion (I/R) injury can be enhanced by adaptation to chronic intermittent hypoxia (CIH), but the changes at the molecular level associated with this adaptation are still not fully explored. Phospholipase A2 (PLA2) plays an important role in phospholipid metabolism and may contribute to membrane destruction under conditions of energy deprivation during I/R. The aim of this study was to determine the effect of CIH (7000 m, 8 h/day, 5 weeks) on the expression of cytosolic PLA2α (cPLA2α) and its phosphorylated form (p-cPLA2α), as well as other related signaling proteins in the left ventricular myocardium of adult male Wistar rats. Adaptation to CIH increased the total content of cPLA2α by 14 % in myocardial homogenate, and enhanced the association of p-cPLA2α with the nuclear membrane by 85 %. The total number of β-adrenoceptors (β-ARs) did not change but the β2/β1 ratio markedly increased due to the elevation of β2-ARs and drop in β1-ARs. In parallel, the amount of adenylyl cyclase decreased by 49 % and Giα proteins increased by about 50 %. Besides that, cyclooxygenase 2 (COX-2) and prostaglandin E2 (PGE2) increased by 36 and 84 %, respectively. In parallel, we detected increased phosphorylation of protein kinase Cα, ERK1/2 and p38 (by 12, 48 and 19 %, respectively). These data suggest that adaptive changes induced in the myocardium by CIH may include activation of cPLA2α and COX-2 via β2-AR/Gi-mediated stimulation of the ERK/p38 pathway.

• Keywords
• Cyclooxygenase 2, Heart, Hypoxia, Ischemia/reperfusion, MAPK, Phospholipase A2, β-Adrenoceptor,
• MeSH
• Receptors, Adrenergic, beta-2 metabolism   MeSH
• Chronic Disease MeSH
• Cyclooxygenase 2 metabolism   MeSH
• Group IV Phospholipases A2 metabolism   MeSH
• Myocardial Ischemia metabolism   pathology   MeSH
• Rats MeSH
• MAP Kinase Signaling System * MeSH
• p38 Mitogen-Activated Protein Kinases metabolism   MeSH
• Rats, Wistar MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Receptors, Adrenergic, beta-2 MeSH
• Cyclooxygenase 2 MeSH
• Group IV Phospholipases A2 MeSH
• p38 Mitogen-Activated Protein Kinases MeSH
• Ptgs2 protein, rat MeSH Browser

The aim of this study was to determine the concentration of phospholipids (PL), plasmalogen components of choline (PC) and ethanolamine (PE) phosphoglycerides (PLPC, PLPE) and fatty acid profile of PL and triacylglycerols (TAG) in developing rat left ventricular myocardium between postnatal day (d) 2 and 100. The steepest increase of total PL (TPL) concentration occurs between d2 and d5, followed by a further slower increase between d20 and d40. Similar developmental changes were observed in PC and PE. The PLPE concentration rises by d10, whereas PLPC does not change during the whole period investigated, except for the transient decline on d5. The concentration of diphosphatidylglycerol (DPG) increases by d60; the steepest rise occurs between d20 and d40. Phosphatidylinositol (PI) concentration rises only by d5. The concentration of phosphatidylserine (PS) decreases between d5 and d10 and then it does not change. Sphingomyelin (SM) concentration is maintained till d10, it declines on d20 and does not change thereafter. The proportion of saturated fatty acids (SFA) increases by d5 in PC, PE, PS and TAG, and by d10 in DPG and PI. After d20 the SFA proportion gradually decline in all lipids. Monounsaturated FA (MUFA) proportion decreases in PC, PE, PI and PS from d2 till d10, and in the weaning period it tends to rise again. In contrast, in DPG and TAG the proportion of MUFA declines during the whole postnatal period. N-6 polyunsaturated FA (PUFA) decrease in all PL by d20 and rise again thereafter; in TAG they decline between d2 and d10 and return to the initial level by d100. N-3 PUFA increase in all PL during the suckling period and decline after weaning; in TAG they increase only by d5 and then they decline. This remodeling of myocardial PL and TAG composition during postnatal development may affect membrane properties and contribute to developmental changes in the function of membrane proteins and cell signaling.

• MeSH
• Choline metabolism   MeSH
• Phosphatidylinositols analysis   metabolism   MeSH
• Phosphatidylserines analysis   metabolism   MeSH
• Phospholipids chemistry   metabolism   MeSH
• Rats MeSH
• Fatty Acids analysis   metabolism   MeSH
• Myocardium chemistry   metabolism   MeSH
• Plasmalogens metabolism   MeSH
• Rats, Wistar MeSH
• Heart growth & development   MeSH
• Heart Ventricles cytology   MeSH
• Triglycerides metabolism   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Choline MeSH
• Phosphatidylinositols MeSH
• Phosphatidylserines MeSH
• Phospholipids MeSH
• Fatty Acids MeSH
• Plasmalogens MeSH
• Triglycerides MeSH

The aim of this study was to examine the effect of hypo- and hyperthyroidism on the phospholipid composition in developing rat heart. The hypothyroid state (PTU) was induced by 0.05% 6-n-propyl-2-thiouracil in drinking water given to nursing mothers from the postnatal day 2-21. The hyperthyroidism (T3) was made by daily injection of 3,3',5-triiodo-L-thyronine (10 microg/100 g body wt) to newborns in the same time period. Age matched intact littermates were taken as euthyroid controls. PTU decreased the concentration of total phospholipids (PL), choline phosphoglycerides (PC), ethanolamine phosphoglycerides (PE) and diphosphatidylglycerol (DPG) and increased the proportion of plasmalogen component of PE (PLPE). T3 increased the concentration of PL, PC, PE, DPG and decreased PLPE in comparison with euthyroid controls. The ratio of saturated/unsaturated fatty acids (FA) in PE was decreased in PTU and increased in T3 group. The ratio of n-6/n-3 polyunsaturated FA in PC, PE and phosphatidylinositol (PI) was increased in PTU due to increase of 18:2n-6 and decrease of 22:6n-3 proportion. T3 decreased this ratio because of decline in 20:4n-6 and rise in 22:6n-3 proportion. Both hypo- and hyperthyroidism decreased the ratio of 20:4n-6/18:2n-6 in the majority of phospholipids. PTU decreased the unsaturation index in PC, PI and phosphatidylserine. It is concluded that thyroid state plays an essential role in the development of membrane phospholipid components in cardiac membranes during the early postnatal period.

• MeSH
• Phospholipids metabolism   MeSH
• Hyperthyroidism metabolism   MeSH
• Hypothyroidism metabolism   MeSH
• Rats MeSH
• Myocardium metabolism   MeSH
• Rats, Wistar MeSH
• Heart growth & development   MeSH
• Body Weight MeSH
• Organ Size MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Phospholipids MeSH

G proteins-coupled signaling pathways appear to play a role in the development of cardiac hypertrophy and its progression to heart failure. The present study aimed to investigate trimeric G proteins and adenylyl cyclase signaling in immature as well as in adult rat myocardium during this process caused by pressure overload. Pressure overload was induced in newborn (2-day-old) rats by abdominal aortic banding and myocardial preparations from left ventricular myocardium of immature (10-day-old) and adult (90-day-old) animals were analyzed for the relative content of different G protein subunits and adenylyl cyclase (AC) by immunoblotting with specific antibodies. A functional status of the AC signaling system was also evaluated. Normal maturation of rat heart was accompanied by increased expression of AC type V/VI and VII and of the long isoform (G(s)alphaL) of G(s)alpha protein. In parallel, the amounts of myocardial G(i)alpha/G(o)alpha proteins tended to decrease, and G(q)alpha/G(11)alpha and Gbeta did not change. Interestingly, whereas fluoride-stimulated AC activity increased in the course of maturation, activity of AC measured under other experimental conditions (stimulation by Mn2+, forskolin or isoproterenol) was lower in adult than in young rat myocardium. Pressure overload did not influence distribution of G proteins in immature myocardium, but considerably decreased the content of G(s)alphaL and increased G(o)alpha proteins in hearts of 90-day-old rats. These hearts exhibited worsened functional reserve as compared to age-matched controls and activity of AC was also markedly lower. A considerable reduction in Mn(2+)-stimulated AC activity together with similar decrease in AC activity determined under other stimulation conditions suggests that it is a function of AC catalytic subunit that is primarily impaired in this model of pressure overload.

• MeSH
• Adenylyl Cyclases genetics   metabolism   MeSH
• Gene Expression MeSH
• Fluorides pharmacology   MeSH
• Hypertrophy, Left Ventricular metabolism   MeSH
• Isoproterenol pharmacology   MeSH
• Cardiomegaly genetics   metabolism   pathology   MeSH
• Cardiotonic Agents pharmacology   MeSH
• Colforsin pharmacology   MeSH
• Rats MeSH
• Manganese pharmacology   MeSH
• Myocardium metabolism   MeSH
• Animals, Newborn * MeSH
• Rats, Wistar MeSH
• Protein Isoforms genetics   metabolism   MeSH
• GTP-Binding Proteins metabolism   MeSH
• Signal Transduction MeSH
• Aging MeSH
• Pressure * MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Adenylyl Cyclases MeSH
• Fluorides MeSH
• Isoproterenol MeSH
• Cardiotonic Agents MeSH
• Colforsin MeSH
• Manganese MeSH
• Protein Isoforms MeSH
• GTP-Binding Proteins MeSH

Addition of glucose to a resting cell suspension of the yeast Saccharomyces cerevisiae was accompanied by marked shifts of the G alpha-protein subunits from the plasma membrane to the cell interior. This process was rapid with half-times between < 10 and 20 s. The decrease of the plasma membrane pool of the Gi alpha/Go alpha- and Gq alpha/Gl 1 alpha-protein subunits correlated with an increase in acid-sensitive forms of these proteins which was recovered in the mitochondrial and/or lysosomal membrane fraction. In contrast to cells from higher organisms glucose-stimulated yeast exhibits an extremely rapid type of the redistribution (internalization). The question remains open as to the functional significance of the internalized forms of the G-proteins as these remain sequestered from the plasma membrane well after glucose has been consumed.

• MeSH
• Glucose pharmacology   MeSH
• Immunoblotting MeSH
• GTP-Binding Proteins analysis   biosynthesis   MeSH
• Saccharomyces cerevisiae drug effects   metabolism   MeSH
• Subcellular Fractions metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Glucose MeSH
• GTP-Binding Proteins MeSH