Tissue spaces in rat heart, liver, and skeletal muscle in vivo

1998 ◽  
Vol 275 (5) ◽  
pp. R1530-R1536 ◽  
Author(s):  
Julie Cieslar ◽  
Ming-Ta Huang ◽  
Geoffrey P. Dobson
Keyword(s):  
Skeletal Muscle ◽  
Rat Heart ◽  
Gastrocnemius Muscle ◽  
Interstitial Space ◽  
Glyceric Acid ◽  
Sprague Dawley ◽  
Tissue Water ◽  
Intracellular Space ◽  
Total Tissue

Tissue spaces were determined in rat heart, liver, and skeletal muscle in vivo using isotopically labeled [14C]inulin. Tracer was injected into the jugular vein of pentobarbital-anesthetized male Sprague-Dawley rats. After a 30-min equilibration period, a blood sample was taken, and heart, liver, and gastrocnemius muscle were excised and immediately freeze clamped at liquid nitrogen temperatures. The extracellular inulin space was 0.209 ± 0.006 ( n = 13), 0.203 ± 0.080 ( n = 7), and 0.124 ± 0.006 (SE) ml/g wet wt tissue ( n = 8) for heart, liver, and skeletal muscle, respectively. Total tissue water was 0.791 ± 0.005 ( n = 9), 0.732 ± 0.002 ( n = 9), and 0.755 ± 0.005 ml/g wet wt tissue ( n = 10) for heart, liver, and skeletal muscle, respectively. Expressed as a percentage of total tissue water, the intracellular space was 73.6, 72.2, and 83.7% for heart, liver, and skeletal muscle, respectively. With use of 2,3-diphospho-d-glyceric acid as a vascular marker, the interstitial space was calculated by subtracting the counts in tissue due to whole blood from total tissue counts and dividing by plasma counts. The interstitial space was 18.8, 22.4, and 14.5% of total tissue water, with accompanying plasma spaces of 7.7, 5.3, and 1.8% for heart, liver, and gastrocnemius muscle, respectively. The tracer method used in this study provides a quantitative assessment of water distribution in tissues of nonnephrectomized rats that has applications for calculation of tissue ion and metabolite concentrations, gradients, and fluxes under normal and pathophysiological conditions.

Stereological analysis of muscle morphology following exposure to repetitive stretch-shortening cycles in a rat model

2006 ◽  
Vol 31 (2) ◽  
pp. 167-179 ◽  
Author(s):  
Brent A Baker ◽  
Robert R Mercer ◽  
Ken B Geronilla ◽  
Michael L Kashon ◽  
G R Miller ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Inflammatory Responses ◽  
Tibialis Anterior Muscle ◽  
Volume Density ◽  
Interstitial Space ◽  
Isometric Contractions ◽  
Sprague Dawley ◽  
Repetitive Motion ◽  
Post Exposure

Repetitive motion is one risk factor associated with contraction-induced muscle injury, which leads to skeletal muscle degeneration, inflammation, and dysfunction. Since current methods are unable to quantify the acute degenerative and inflammatory responses of muscle tissue concurrently, the purpose of this study was to quantify the temporal myofiber response after exposure to injurious stretch-shortening cycles (SSCs) using a standardized stereological technique. Functional testing was performed on the ankle dorsiflexor muscles of Sprague-Dawley rats in vivo. Rats were anesthetized and exposed to 15 sets of 10 SSCs. Control rats were exposed to 15 sets of single isometric contractions of the same stimulation duration. Changes in muscle morphometry were assessed at 0.5, 24, 48, 72, and 240 h post-exposure to quantify the degree of myofiber degeneration and inflammation in the tibialis anterior muscle from each group. There was an increase in the volume density and average thickness of degenerating myofibers over time in the muscle collected from rats exposed to SSCs (p < 0.0001) that was significantly greater than in muscle exposed to isometric contractions at 24, 48, and 72 h post-exposure (p = 0.003). The volume density of degenerative myofibers was associated with functional deficits at 48 h. Stereological quantification of degenerative myofibers and interstitial space changes were associated with functional defects 48-72 h after SSC-induced injury, thus demonstrating stereology is an accurate measure of SSC-induced skeletal muscle injury.Key words: stereology, morphometry, myofiber degeneration, interstitial space, stretch-shortening cycles.

Espace extracellulaire, perméabilité à l'inuline et accumulation de L-alanine dans l'intestin isolé de Grenouille

1973 ◽  
Vol 51 (1) ◽  
pp. 22-28
Author(s):  
Joël de la Noüe ◽  
André Gagnon
Keyword(s):  
Extracellular Space ◽  
Muscle Layer ◽  
Solute Concentration ◽  
Tissue Water ◽  
Intracellular Amino Acid ◽  
Inulin Space ◽  
Total Tissue ◽  
Frog Intestine

In order to calculate the intracellular concentration of accumulated L-alanine, the extracellular space (inulin-14C) of frog intestine was measured. To check the validity of the technique, frog liver and gastrocnemius were used too. By scraping proximal portions of intestine, the inulin space was found to be similar (around 20% of total tissue water) in both the muscle layer and the mucosa. The mucosal epithelium is an imperfect barrier to inulin while the serosa is very permeable. These results suggest that the interstitial solute concentration is best approximated by equating it to that of the serosal solution. The in vitro inulin space, compared to the in vivo one, increases with time, as does the cellular hydration. The data obtained from measurements of extracellular space and from L-alanine uptake show that the intracellular amino acid is in a free state.

Hemorrhagic shock impairs myocardial cell volume regulation and membrane integrity in dogs

1987 ◽  
Vol 252 (6) ◽  
pp. H1203-H1210
Author(s):  
J. W. Horton
Keyword(s):  
Hemorrhagic Shock ◽  
Cell Volume ◽  
Volume Regulation ◽  
Membrane Integrity ◽  
Cell Volume Regulation ◽  
Calcium Entry ◽  
Tissue Water ◽  
Total Tissue

An in vitro myocardial slice technique was used to quantitate alterations in cell volume regulation and membrane integrity after 2 h of hemorrhagic shock. After in vitro incubation in Krebs-Ringer-phosphate medium containing trace [14C]inulin, values (ml H2O/g dry wt) for control nonshocked myocardial slices were 4.03 +/- 0.11 (SE) for total water, 2.16 +/- 0.07 for inulin impermeable space, and 1.76 +/- 0.15 for inulin diffusible space. Shocked myocardial slices showed impaired response to cold incubation (0 degrees C, 60 min). After 2 h of in vivo shock, total tissue water, inulin diffusible space, and inulin impermeable space increased significantly (+19.2 +/- 2.4, +8.1 +/- 1.9, +34.4 +/- 6.1%, respectively) for subendocardium, whereas changes in subepicardium parameters were minimal. Shock-induced cellular swelling was accompanied by an increased total tissue sodium, but no change in tissue potassium. Calcium entry blockade in vivo (lidoflazine, 20 micrograms X kg-1 X min-1 during the last 60 min of shock) significantly reduced subendocardial total tissue water as compared with shock-untreated dogs. In addition, calcium entry blockade reduced shock-induced increases in inulin impermeable space and inulin diffusible space. In vitro myocardial slice studies confirm alterations in subendocardial membrane integrity after 2 h of in vivo hemorrhagic shock. Shock-induced abnormalities in myocardial cell volume regulation are reduced by calcium entry blockade in vivo.

Mammalian target of rapamycin pathway is up-regulated by both acute endurance exercise and chronic muscle contraction in rat skeletal muscle

2013 ◽  
Vol 38 (8) ◽  
pp. 862-869 ◽  
Author(s):  
Brittany A. Edgett ◽  
Melanie L. Fortner ◽  
Arend Bonen ◽  
Brendon J. Gurd
Keyword(s):  
Skeletal Muscle ◽  
Endurance Exercise ◽  
Gastrocnemius Muscle ◽  
Contractile Activity ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Pathway ◽  
Initiation Factor ◽  
Eukaryotic Initiation Factor ◽  
Sprague Dawley ◽  
Sprague Dawley Rats

This study examined changes in the expression of translation initiation regulatory proteins and mRNA following both an acute bout of endurance exercise and chronic muscle contractile activity. Female Sprague Dawley rats ran for 2 h at 15 m·min−1 followed by an increase in speed of 5 m·min−1 every 5 min until volitional fatigue. The red gastrocnemius muscle was harvested from nonexercised animals (control; n = 6) and from animals that exercised either immediately after exercise (n = 6) or following 3 h of recovery from exercise (n = 6). Compared with control, ribosomal protein S6 (rpS6) mRNA was elevated (p < 0.05) at both 0 h (+32%) and 3 h (+47%). Both a catalytic subunit of eukaryotic initiation factor 2B (eIF2Bε) (+127%) and mammalian target of rapamycin (mTOR) mRNA (+44%) were increased at 3 h, compared with control. Phosphorylation of mTOR (+40%) and S6 kinase 1 (S6K1) (+266%) were increased immediately after exercise (p < 0.05). Female Sprague Dawley rats also underwent chronic stimulation of the peroneal nerve continuously for 7 days. The red gastrocnemius muscle was removed 24 h after cessation of the stimulation. Chronic muscle stimulation increased (p < 0.05) mTOR protein (+74%), rpS6 (+31%), and eukaryotic initiation factor 2α (+44%, p = 0.069), and this was accompanied by an increase in cytochrome c (+31%). Increased resting phosphorylation was observed for rpS6 (+51%) (p < 0.05) but not for mTOR or eukaryotic initiation factor 4E binding protein 1. These experiments demonstrate that both acute and chronic contractile activity up-regulate the mTOR pathway and mitochondrial content in murine skeletal muscle. This up-regulation of the mTOR pathway may increase translation efficiency and may also represent an important control point in exercise-mediated mitochondrial biogenesis.

In vivo leucine oxidation at rest and during two intensities of exercise

1982 ◽  
Vol 53 (4) ◽  
pp. 947-954 ◽  
Author(s):  
P. W. Lemon ◽  
F. J. Nagle ◽  
J. P. Mullin ◽  
N. J. Benevenga
Keyword(s):  
Skeletal Muscle ◽  
Specific Activity ◽  
Muscle Metabolism ◽  
Weighted Average ◽  
Mixed Diet ◽  
Sprague Dawley ◽  
Tracer Dose ◽  
Sprague Dawley Rats ◽  
14Co2 Production

After ingestion of a mixed diet containing a tracer dose (10 muCi) of L-[1–14C]leucine (Leu), 32 male Sprague-Dawley rats (70–90 g) remained at rest (R) or completed 1 h exercise at 80 (E80) or 40% VO2max (E40). 14CO2 production was assessed for 6 h (exercise occurred from h 2 to 3). Four rats were killed at 2, 3, 4, and 6 h (R), at 3 and 6 h (E80), and at 6 h (E40). Determinations were 1) tissue specific activity dpm X mumol-1 from a) mixed skeletal muscle (gastrocnemius, soleus, quadriceps, and hamstrings) and b) liver and 2) radioactivity remaining in the gastrointestinal tract (GIT). Leu oxidized (mumol) was estimated (14 CO2 dpm X tissue sp act dpm-1 X mumol-1) independently from skeletal muscle and liver. Results were 1) 14CO2 production increased in both E80 and E40 compared with R (P less than 0.05), 2) E80 14CO2 increase was greater than E40 (P less than 0.05), 3) GIT absorption was reduced in E80 and E40 compared with R (P less than 0.05), and 4) exercise Leu oxidation (weighted average of tissue estimates) was 26% greater than R (P less than 0.05). The origin and site of the increased Leu oxidation cannot be determined from the present data; however, due to the magnitude of increase in skeletal muscle metabolism relative to other tissues during exercise, it is probable that skeletal muscle plays a significant role.

Enhanced skeletal muscle arteriolar reactivity to ANG II after recovery from ischemic acute renal failure

2005 ◽  
Vol 289 (6) ◽  
pp. R1770-R1776 ◽  
Author(s):  
David P. Basile ◽  
Deborah L. Donohoe ◽  
Shane A. Phillips ◽  
Jefferson C. Frisbee
Keyword(s):  
Skeletal Muscle ◽  
Renal Failure ◽  
Acute Renal Failure ◽  
Pressor Response ◽  
Gracilis Muscle ◽  
Ang Ii ◽  
Sprague Dawley

In addition to the long-term renal complications, previous studies suggested that after acute renal failure (ARF), rats manifest an increased pressor response to an overnight infusion of ANG II. The present study tested whether recovery from ARF results in alterations in sensitivity to the peripheral vasculature. ARF was induced in Sprague-Dawley rats by 45 min of bilateral renal ischemia and reperfusion. Animals were allowed to recover renal structure and function for 5–8 wk, after which the acute pressor responses to ANG II were evaluated either in vivo in in situ skeletal muscle arterioles or in isolated gracilis muscle arteries in vitro. Baseline arterial pressure was not different in ARF rats vs. sham-operated controls, although ARF rats exhibited an enhanced pressor response to bolus ANG II infusion compared with control rats. Steady-state plasma ANG II concentration and plasma renin activity were similar between ARF and control rats. Constrictor reactivity of in situ cremasteric arterioles from ARF rats was enhanced in response to increasing concentrations of ANG II; however, no difference was observed in arteriolar responses to elevated Po2, norepinephrine, acetylcholine, or sodium nitroprusside. Isolated gracilis muscle arteries from ARF rats also showed increased vasoconstriction in response to ANG II but not norepinephrine. In conclusion, recovery from ischemic ARF is not associated with hypertension but is associated with increased arteriolar constrictor reactivity to ANG II. Although the mechanisms of this altered responsiveness are unclear, such changes may relate, in part, to cardiovascular complications in patients with ARF and/or after renal transplant.

scholarly journals Water Compartmentalization and Spread of Ischemic Injury in Thick-Slice Ischemia Model

2002 ◽  
Vol 22 (1) ◽  
pp. 80-88 ◽  
Author(s):  
Sabina Hrabětová ◽  
Kevin C. Chen ◽  
Daniel Masri ◽  
Charles Nicholson
Keyword(s):  
Water Content ◽  
Extracellular Space ◽  
Cell Swelling ◽  
Extracellular Potassium ◽  
Tissue Water ◽  
Diffusion Analysis ◽  
Artificial Cerebrospinal Fluid ◽  
Water Redistribution ◽  
Total Tissue

Water compartmentalization was studied in a thick-slice (1000 μm) model of ischemia by combining water-content measurements with extracellular diffusion analysis. Thick slices bathed in artificial cerebrospinal fluid continually gained water. Total tissue water content was increased by 67% after 6 hours of the incubation. Diffusion measurements using the tetramethylammonium method showed that the extracellular space, typically occupying 20% of brain tissue in vivo, was decreased to 10% at 30 minutes and 15% at 6 hours in both deep and superficial layers of thick slices. Quantification of water compartmentalization revealed that water moved initially from the extracellular space into the cells. Later, however, both compartments gained water. The initial cell swelling was accompanied by dramatic shifts in potassium. An initial rise of extracellular potassium to about 50 mmol/L was measured with a potassium-selective microelectrode positioned in the center of the thick slice; the concentration decreased slowly afterwards. Potassium content analysis revealed a 63% loss of tissue potassium within two hours of the incubation. In thick slices, ionic shifts, water redistribution, and a loss of synaptic transmission occur in both deep and superficial layers, indicating the spread of ischemic conditions even to areas with an unrestricted supply of nutrients.

scholarly journals Monosaccharide transport in the mammary gland of the intact lactating rat

1984 ◽  
Vol 218 (1) ◽  
pp. 213-219 ◽  
Author(s):  
L C Threadgold ◽  
N J Kuhn
Keyword(s):  
Mammary Gland ◽  
Glucose Transport ◽  
Intracellular Water ◽  
Limiting Factor ◽  
Transport Capacity ◽  
Tissue Water ◽  
Monosaccharide Transport ◽  
Rate Limiting ◽  
Total Tissue

The Michaelis-Menten equation for the utilization of competing substrates was applied to the uptake of 2-deoxy[3H]glucose into the mammary gland of anaesthetized lactating rats. Intracellular water was calculated from total tissue water and sucrose space. Fed rats had a mean transport capacity of 2.2 mumol/min per g of tissue, giving an actual glucose transport in vivo of 1.1 mumol/min per g. Transport decreased by 90% on overnight starvation and returned to normal by 2 h of re-feeding. Similar changes were observed in the 1 min or 5 min transport of circulating 3-O-methylglucose. Transport of 3-O-methylglucose in starved rats was restored towards normal by insulin. In fed rats it increased between parturition and day 12 of lactation. The findings support the proposal that transport is a rate-limiting factor in the mammary utilization of carbohydrate.

scholarly journals Protein synthesis in skeletal muscle of the perfused rat hemicorpus compared with rates in the intact animal

1983 ◽  
Vol 214 (2) ◽  
pp. 433-442 ◽  
Author(s):  
V R Preedy ◽  
P J Garlick
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Gastrocnemius Muscle ◽  
Intact Animal ◽  
Rna Content ◽  
Isolated Rat

The rate of protein synthesis was measured in muscles of the perfused rat hemicorpus, and values were compared with rates obtained in whole animals. In gastrocnemius muscle of fed rats the rate of synthesis measured in the hemicorpus was the same as that in the whole animal. However, in plantaris, quadriceps and soleus muscles rates were higher in the hemicorpus than those in vivo. In the hemicorpus, starvation for 1 day decreased the rate of protein synthesis in gastrocnemius and plantaris muscles, in parallel with decreases in the RNA content, but the soleus remained unaffected. Similar effects of starvation were observed in vivo, so that the relationships between rates in vivo and in the hemicorpus were the same as those in fed rats. Proteins of quadriceps and plantaris muscles were separated into sarcoplasmic and myofibrillar fractions. The rate of synthesis in the sarcoplasmic fraction of the hemicorpus from fed rats was similar to that in vivo, but synthesis in the myofibrillar fraction was greater. In the plantaris of starved rats the rates of synthesis in both fractions were lower, but the relationships between rates measured in vivo and in the perfused hemicorpus were similar to those seen in fed rats. The addition of insulin to the perfusate of the hemicorpus prepared from 1-day-starved animals increased the rates of protein synthesis per unit of RNA in gastrocnemius and plantaris muscles to values above those seen in fed animals when measured in vivo or in the hemicorpus. Insulin had no effect on the soleus. Overall, the rates of protein synthesis in the hemicorpus differed from those in vivo. However, the effect of starvation when measured in the whole animal was very similar to that measured in the isolated rat hemicorpus when insulin was omitted from the perfusate.

Protein turnover in rat skeletal muscle: effects of hypophysectomy and growth hormone.

1978 ◽  
Vol 234 (1) ◽  
pp. E38 ◽  
Author(s):  
K E Flaim ◽  
J B Li ◽  
L S Jefferson
Keyword(s):  
Skeletal Muscle ◽  
Growth Hormone ◽  
Protein Synthesis ◽  
Protein Turnover ◽  
Gastrocnemius Muscle ◽  
Growth Hormone Treatment ◽  
Hormone Replacement ◽  
Hormone Treatment ◽  
Rat Skeletal Muscle

The role of growth hormone in regulating protein turnover was examined in a perfused preparation of rat skeletal muscle. The perfused muscle maintained in vivo levels of ATP and creatine phosphate and exhibited constant rates of oxygen consumption and protein synthesis. Hypophysectomy reduced the rate of protein synthesis, the concentration of RNA, and the efficiency of protein synthesis in gastrocnemius muscle to 30, 46, and 66 percent of normal, respectively. In vivo treatment of hypophysectomized (hypox) rats with bovine growth hormone (250 microgram/day for 5 days) resulted in small increases in protein synthesis and RNA, whereas synthesis/RNA was returned to near normal. Elevation of ribosomal subunits in psoas muscle indicated an inhibition of peptide-chain initiation in hypox rats that was reversed by in vivo growth hormone treatment. Thus, hypox rats exhibited both a decreased capacity and a decreased efficiency of protein synthesis. Growth hormone replacement primarily increased efficiency of protein synthesis. The rate of protein degradation and the activity of cathepsin D in gastrocnemius muscle were decreased by hypophysectomy. Growth hormone treatment had no significant effect on degradation.

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