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Lamarre SG, MacCormack TJ, Bourloutski É, Callaghan NI, Pinto VD, Andrade JP, Sykes AV, Driedzic WR. Interrelationship Between Contractility, Protein Synthesis and Metabolism in Mantle of Juvenile Cuttlefish ( Sepia officinalis). Front Physiol 2019; 10:1051. [PMID: 31507433 PMCID: PMC6716058 DOI: 10.3389/fphys.2019.01051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 07/31/2019] [Indexed: 11/13/2022] Open
Abstract
Young juvenile cuttlefish (Sepia officinalis) can grow at rates as high as 12% body weight per day. How the metabolic demands of such a massive growth rate impacts muscle performance that competes for ATP is unknown. Here, we integrate aspects of contractility, protein synthesis, and energy metabolism in mantle of specimens weighing 1.1 g to lend insight into the processes. Isolated mantle muscle preparations were electrically stimulated and isometric force development monitored. Preparations were forced to contract at 3 Hz for 30 s to simulate a jetting event. We then measured oxygen consumption, glucose uptake and protein synthesis in the hour following the stimulation. Protein synthesis was inhibited with cycloheximide and glycolysis was inhibited with iodoacetic acid in a subset of samples. Inhibition of protein synthesis impaired contractility and decreased oxygen consumption. An intact protein synthesis is required to maintain contractility possibly due to rapidly turning over proteins. At least, 41% of whole animal ṀO2 is used to support protein synthesis in mantle, while the cost of protein synthesis (50 μmol O2 mg protein–1) in mantle was in the range reported for other aquatic ectotherms. A single jetting challenge stimulated protein synthesis by approximately 25% (2.51–3.12% day–1) over a 1 h post contractile period, a similar response to that which occurs in mammalian skeletal muscle. Aerobic metabolism was not supported by extracellular glucose leading to the contention that at this life stage either glycogen or amino acids are catabolized. Regardless, an intact glycolysis is required to support contractile performance and protein synthesis in resting muscle. It is proposed that glycolysis is needed to maintain intracellular ionic gradients. Intracellular glucose at approximately 3 mmol L–1 was higher than the 1 mmol L–1 glucose in the bathing medium suggesting an active glucose transport mechanism. Octopine did not accumulate during a single physiologically relevant jetting challenge; however, octopine accumulation increased following a stress that is sufficient to lower Arg-P and increase free arginine.
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Affiliation(s)
- Simon G Lamarre
- Département de Biologie, Université de Moncton, Moncton, NB, Canada
| | - Tyson J MacCormack
- Department of Chemistry and Biochemistry, Mount Allison University, Sackville, NB, Canada
| | | | - Neal I Callaghan
- Faculty of Applied Science and Engineering, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Translational Biology and Engineering Program, Ted Rogers Centre for Heart Research, Toronto, ON, Canada
| | - Vanessa D Pinto
- Centro de Ciências do Mar do Algarve, Campus de Gambelas, Universidade do Algarve, Faro, Portugal
| | - José P Andrade
- Centro de Ciências do Mar do Algarve, Campus de Gambelas, Universidade do Algarve, Faro, Portugal
| | - Antonio V Sykes
- Centro de Ciências do Mar do Algarve, Campus de Gambelas, Universidade do Algarve, Faro, Portugal
| | - William R Driedzic
- Department of Ocean Sciences, Memorial University, St. John's, NL, Canada
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MacCormack TJ, Driedzic WR. The impact of hypoxia on in vivo glucose uptake in a hypoglycemic fish,Myoxocephalus scorpius. Am J Physiol Regul Integr Comp Physiol 2007; 292:R1033-42. [PMID: 17008463 DOI: 10.1152/ajpregu.00308.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mechanisms controlling carbohydrate utilization in teleost fish are poorly understood, particularly in the heart. Tissue glucose uptake and cardiovascular characteristics were measured in the short-horned sculpin, Myoxocephalus scorpius, a species exhibiting low blood glucose levels, during normoxia and hypoxia to assess the role of adenosine receptors in the control of glucose uptake and anaerobic metabolism. As expected, hypoxia exposure (300 min at 2 mg/l dissolved oxygen) resulted in a bradycardia and plasma lactate accumulation, but glucose uptake rates did not change in heart, brain, gill, spleen, and white muscle. Plasma glucose-to-intracellular glucose ratios indicated that glucose uptake was the rate-limiting step in glucose utilization. The majority of intracellular glucose was unphosphorylated, however, suggesting that hexokinase is also important in controlling the tissue glucose gradient. During hypoxia, the cholinergic blocker atropine resulted in tachycardia but did not significantly change tissue glucose uptake rates or heart and brain adenosine levels. In contrast, the combined treatment of atropine and an adenosine receptor blocker [8-( p-sulfophenyl)theophylline] during hypoxia increased heart glucose uptake to levels fivefold higher than normoxic fish, with no additive effects on cardiovascular parameters. Significant tissue lactate accumulation was observed in this group of fish, signifying that adenosine receptors may depress anaerobic metabolism, even though tissue adenosine accumulation was absent during hypoxia. White muscle accumulated glucose during normoxia, suggesting the presence of gluconeogenic pathways or active uptake mechanisms not previously described in this tissue.
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Affiliation(s)
- Tyson J MacCormack
- Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.
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Maccormack TJ, Lewis JM, Almeida-Val VMF, Val AL, Driedzic WR. Carbohydrate management, anaerobic metabolism, and adenosine levels in the armoured catfish,Liposarcus pardalis (castelnau), during hypoxia. ACTA ACUST UNITED AC 2006; 305:363-75. [PMID: 16493645 DOI: 10.1002/jez.a.274] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The armoured catfish, Liposarcus pardalis, tolerates severe hypoxia at high temperatures. Although this species can breathe air, it also has a strong anaerobic metabolism. We assessed tissue to plasma glucose ratios and glycogen and lactate in a number of tissues under "natural" pond hypoxia, and severe aquarium hypoxia without aerial respiration. Armour lactate content and adenosine in brain and heart were also investigated. During normoxia, tissue to plasma glucose ratios in gill, brain, and heart were close to one. Hypoxia increased plasma glucose and decreased tissue to plasma ratios to less than one, suggesting glucose phosphorylation is activated more than uptake. High normoxic white muscle glucose relative to plasma suggests gluconeogenesis or active glucose uptake. Excess muscle glucose may serve as a metabolic reserve since hypoxia decreased muscle to plasma glucose ratios. Mild pond hypoxia changed glucose management in the absence of lactate accumulation. Lactate was elevated in all tissues except armour following aquarium hypoxia; however, confinement in aquaria increased armour lactate, even under normoxia. A stress-associated acidosis may contribute to armour lactate sequestration. High plasma lactate levels were associated with brain adenosine accumulation. An increase in heart adenosine was triggered by confinement in aquaria, although not by hypoxia alone.
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Affiliation(s)
- Tyson James Maccormack
- Ocean Sciences Centre, Memorial University of Newfoundland, St. John's, Newfoundland, Canada A1C 5S7.
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Clow KA, Rodnick KJ, MacCormack TJ, Driedzic WR. The regulation and importance of glucose uptake in the isolated Atlantic cod heart: rate-limiting steps and effects of hypoxia. J Exp Biol 2004; 207:1865-74. [PMID: 15107441 DOI: 10.1242/jeb.00965] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
This study investigated the regulation of glucose uptake in Atlantic cod(Gadus morhua) hearts. Isolated hearts were perfused with or without glucose in the medium, under either normoxic or severely hypoxic conditions. Working at basal levels, hearts did not require extracellular glucose to maintain power under aerobic conditions. However, cardiac performance was significantly reduced without exogenous glucose under oxygen-limiting conditions. The addition of the glucose transporter inhibitor cytochalasin B caused hypoxic hearts to fail early, and hearts perfused with a glucose analogue, 2-deoxyglucose (2-DG), increased glucose uptake 3-fold under hypoxia. The uptake of 2-DG was only partially inhibited when cytochalasin B was added to the medium. Isolated ventricle strips were also incubated in the presence of 2-DG and the extracellular marker mannitol. Glucose uptake(glucose transport plus intracellular phosphorylation) was assessed by measuring the initial rate of 2-deoxyglucose-6-phosphate (2-DG-6-P)accumulation. At 1 mmol l-1 2-DG, the rate of 2-DG uptake remained linear for 60 min, and 2-DG-6-P, but not free 2-DG, accumulation was increased. The fact that intracellular 2-DG did not increase indicates that glucose transport is the rate-limiting step for glucose utilization in non-stimulated cardiac tissue. Replacement of Na+ by choline in the incubation medium did not affect 2-DG uptake, providing evidence that Na+-coupled glucose transport is absent in cod cardiac tissue. Similar to cytochalasin B, glucose uptake was also inhibited by phloridzin,suggesting that facilitated, carrier-mediated glucose transport occurs in cod hearts. Under the conditions employed in these experiments, it is clear that(1) activation of glucose transport is required to support hypoxic performance, (2) the rate-limiting step for glucose utilization is glucose transport rather than glucose phosphorylation, (3) 2-DG uptake accurately reflects glucose transport activity and (4) glucose uptake in cod hearts does not involve an Na+-dependent mechanism.
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Affiliation(s)
- Kathy A Clow
- Ocean Sciences Centre, Memorial University of Newfoundland, St John's, Newfoundland, Canada, A1C 5S7
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Marunaka Y. Effects of internal Na and external K concentrations on Na/K coupling of Na,K-pump in frog skeletal muscle. J Membr Biol 1988; 101:19-31. [PMID: 2835486 DOI: 10.1007/bf01872816] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To clarify the dependency of the Na/K coupling of the Na,K-pump on internal Na and external K concentrations in skeletal muscle, the ouabain-induced change in membrane potential, the ouabain-induced change in Na efflux and the membrane resistance were measured at various internal Na and external K concentrations in bullfrog sartorius muscle. Upon raising the internal Na concentration from 6 mmol/kg muscle water to 20 mmol/kg muscle water, the magnitude of the ouabain-induced change in membrane potential increased about eightfold and the magnitude of the ouabain-induced change in Na efflux increased about fivefold while the membrane resistance was not significantly changed. As the external K concentration increased from 1 to 10 mM, the magnitude of the ouabain-induced change in membrane potential decreased (1/5.5 fold), while the magnitude of the ouabain-induced change in Na efflux increased (about 1.5-fold). The membrane resistance decreased upon raising the external K concentration from 1 to 10 mM (1/2-fold). These observations imply that the values of the Na/K coupling of the Na,K-pump increases upon raising the internal Na concentration and decreases upon raising the external K concentration.
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Affiliation(s)
- Y Marunaka
- Department of Physiology, Shiga University of Medical Science, Ohtsu, Japan
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Marunaka Y. Relationship between ionic surroundings and insulin actions on glucose transport and Na,K-pump in muscles. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. A, COMPARATIVE PHYSIOLOGY 1988; 89:103-12. [PMID: 2452047 DOI: 10.1016/0300-9629(88)91065-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
1. It is well known that insulin has various effects on glucose transport and the Na,K-pump in muscles. It is also known to have some effects on the membrane potential--in general, insulin induces a hyperpolarization of the membrane in muscles. Furthermore, it is suggested that the actions of insulin are modified by changes in ionic surroundings. 2. In this review article, the actions of ionic surroundings and insulin on glucose transport in muscles are discussed; in particular, the effects of changes in extracellular and/or intracellular concentrations of Na, K, Ca and H ions will be mentioned. 3. The actions of ionic surroundings and insulin on the Na,K-pump in muscles are discussed; in particular, the effects of changes in extracellular an/or intracellular concentrations of Na, K, Ca and H ions will be examined. 4. The relationship between the actions of ionic surroundings and insulin are discussed. 5. In particular, the effects of changes in ionic surroundings on the insulin-induced hyperpolarization of the membrane are discussed by relating it to the Na,K-pump function. The relationship between the insulin-induced change in membrane potential and glucose transport will be also mentioned.
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Affiliation(s)
- Y Marunaka
- Department of Physiology, Shiga University of Medical Science, Ohtsu, Japan
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Omatsu-Kanbe M, Kitasato H. Effects of detergents on Na+ + K+-dependent ATPase activity in plasma-membrane fractions prepared from frog muscles. Studies of insulin action on Na+ and K+ transport. Biochem J 1987; 246:583-8. [PMID: 2825643 PMCID: PMC1148320 DOI: 10.1042/bj2460583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The increase in Na+/K+ transport activity in skeletal muscles exposed to insulin was analysed. Plasma-membrane fractions were prepared from frog (Rana catesbeiana) skeletal muscles, and examination of the Na,K-ATPase (Na+ + K+-dependent ATPase) activity showed that it was insensitive to ouabain. In contrast, plasma-membrane fractions prepared from ouabain-pretreated muscles, by the same procedures, showed extremely low Na,K-ATPase activity. On adding saponin to the membrane suspension, the Na,K-ATPase activity increased, according to the detergent concentration. The maximum activity was about twice the control value, at 0.33 mg of saponin/mg of protein. Thus saponin makes vesicle membranes leaky, allowing ouabain in assay solutions to reach receptors on the inner surface of vesicles. Addition of insulin to saponin-treated membrane suspensions had no effect on the Na,K-ATPase activity, whereas the maximum activity of Na,K-ATPase in whole muscles was stimulated by exposure to insulin. The results show that the stimulation of Na+/K+ transport by insulin is not directly due to insulin binding to receptors on the cell surface, but rather support the view that the increase in the Na,K-ATPase induced by insulin requires an alteration of intracellular events.
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Affiliation(s)
- M Omatsu-Kanbe
- Department of Physiology, Shiga University of Medical Science, Ohtsu, Japan
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