Effect of acute acidosis on protein and amino acid metabolism in rats

Šafránek, Roman; Holeček, Milan; Kadlčíková, Jana; Šprongl, Luděk; Mislanova, Csilla; Kukan, M; Chládek, Jaroslav

doi:10.1016/s0261-5614(03)00041-4

Cited by 26 publications

(19 citation statements)

References 38 publications

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“…Control and experimental incubations of the same rat were compared. The viability of incubated muscles was previously confirmed in our laboratory (30) as well as by other authors (8).…”

Section: Methodssupporting

confidence: 52%

The effect of new proteasome inhibitors, belactosin A and C, on protein metabolism in isolated rat skeletal muscle

et al. 2009

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The proteasome inhibitors are used as research tools to study of the ATP-dependent ubiquitin-proteasome system. Some of them are at present undergoing clinical trials to be used as therapeutic agents for cancer or inflammation. These diseases are often accompanied by muscle wasting. We herein demonstrate findings about new proteasome inhibitors, belactosin A and C, and their direct effect on protein metabolism in rat skeletal muscle. M. soleus (SOL) and m. extensor digitorum longus (EDL) were dissected from both legs of male rats (40-60 g) and incubated in a buffer containing belactosin A or C (30 microM) or no inhibitor. The release of amino acids into the medium was estimated using high performance liquid chromatography to calculate total and myofibrillar proteolysis. Chymotrypsin-like activity (CTLA) of proteasome and cathepsin B, L activity were determined by fluorometric assay. Protein synthesis and leucine oxidation were detected using specific activity of L-[1-14C] leucine added to medium. Inhibited and control muscles from the same rat were compared using paired t-test. The results indicate that after incubation with both belactosin A and C total proteolysis and CTLA of proteasome decreased while cathepsin B, L activity did not change in both SOL and EDL. Leucine oxidation was significantly enhanced in SOL, protein synthesis decreased in EDL. Myofibrillar proteolysis was reduced in both muscles in the presence of belactosin A only. In summary, belactosin A and C affected basic parameters of protein metabolism in rat skeletal muscle. The response was both muscle- and belactosin-type-dependent.

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“…Control and experimental incubations of the same rat were compared. The viability of incubated muscles was previously confirmed in our laboratory (30) as well as by other authors (8).…”

Section: Methodssupporting

confidence: 52%

The effect of new proteasome inhibitors, belactosin A and C, on protein metabolism in isolated rat skeletal muscle

et al. 2009

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“…36). Some of these have been based on ex vivo proteolysis experiments performed with prepubertal rat muscles (12,26,28,32,37,47,50). Here we found that ␤-adrenergic agonists isoproterenol (nonselective) and formoterol (␤ 2 -selective) also reduced proteolysis of adult rat skeletal muscle by 12-20%.…”

Section: Discussionmentioning

confidence: 72%

The lumbrical muscle: a novel in situ system to evaluate adult skeletal muscle proteolysis and anticatabolic drugs for therapeutic purposes

Bergantin

Figueiredo

Godinho

2011

Journal of Applied Physiology

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Bergantin LB, Figueiredo LB, Godinho RO. The lumbrical muscle: a novel in situ system to evaluate adult skeletal muscle proteolysis and anticatabolic drugs for therapeutic purposes. J Appl Physiol 111: 1710 -1718, 2011. First published September 15, 2011 doi:10.1152/japplphysiol.00586.2011.-The molecular regulation of skeletal muscle proteolysis and the pharmacological screening of anticatabolic drugs have been addressed by measuring tyrosine release from prepubertal rat skeletal muscles, which are thin enough to allow adequate in vitro diffusion of oxygen and substrates. However, the use of muscle at accelerated prepubertal growth has limited the analysis of adult muscle proteolysis or that associated with aging and neurodegenerative diseases. Here we established the adult rat lumbrical muscle (4/hindpaw; 8/rat) as a new in situ experimental model for dynamic measurement of skeletal muscle proteolysis. By incubating lumbrical muscles attached to their individual metatarsal bones in Tyrode solution, we showed that the muscle proteolysis rate of adult and aged rats (3-4 to 24 mo old) is 45-25% of that in prepubertal animals (1 mo old), which makes questionable the usual extrapolation of proteolysis from prepubertal to adult/senile muscles. While acute mechanical injury or 1-to 7-day denervation increased tyrosine release from adult lumbrical muscle by up to 60%, it was reduced by 20 -28% after 2-h incubation with ␤-adrenoceptor agonists, forskolin or phosphodiesterase inhibitor IBMX. Using inhibitors of 26S-proteasome (MG132), lysosome (methylamine), or calpain (E64/leupeptin) systems, we showed that ubiquitin-proteasome is accountable for 40 -50% of total lumbrical proteolysis of adult, middle-aged, and aged rats. In conclusion, the lumbrical model allows the analysis of muscle proteolysis rate from prepubertal to senile rats. By permitting eight simultaneous matched measurements per rat, the new model improves similar protocols performed in paired extensor digitorum longus (EDL) muscles from prepubertal rats, optimizing the pharmacological screening of drugs for anticatabolic purposes.

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“…Thus, the alcohol-induced maternal hypercapnea in this study would directly result in fetal hypercapnea producing both intracellular and extracellular brain acidosis. Brain acidosis has been documented to cause neuronal and glial death (Goldman et al, 1989;Kraig et al, 1987;Staub et al, 1990) via multiple mechanisms that may involve exacerbation of free radicalmediated injury (Ying et al, 1999), alteration of gene expression and protein synthesis by perturbing intracellular signal transduction pathways (Siesjo et al, 1996), alteration of protein and amino acid metabolism (Milley, 1997;Safranek et al, 2003), decrease of serum IGF-1 concentrations (Brungger et al, 1997;Challa et al, 1993;Wiederkehr and Krapf, 2001), and increase of glucocorticoid levels (Perez et al, 1979;Wiederkehr and Krapf, 2001;Wood and Chen, 1989). It should be noted that the threshold for acidemia or acidosis-induced death in neurons and glia is not a fixed value (Nedergaard et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

All Three Trimester Binge Alcohol Exposure Causes Fetal Cerebellar Purkinje Cell Loss in the Presence of Maternal Hypercapnea, Acidemia, and Normoxemia: Ovine Model

Ramadoss

Lunde

Piña

et al. 2007

Alcoholism Clin & Exp Res

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These findings demonstrate in an ovine model where all 3 trimester equivalent of brain growth occur in utero that the fetal cerebellar Purkinje cells are more sensitive to the timing of alcohol exposure and less so to the duration of exposure. Decreases in maternal P(a)O(2) were not detected, suggesting that maternal hypoxia does not play a role in fetal Purkinje cell loss. And finally, we conclude that alcohol-induced changes in maternal arterial pH may play a role in alcohol-mediated developmental brain injury.

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Effect of acute acidosis on protein and amino acid metabolism in rats

Cited by 26 publications

References 38 publications

The effect of new proteasome inhibitors, belactosin A and C, on protein metabolism in isolated rat skeletal muscle

The effect of new proteasome inhibitors, belactosin A and C, on protein metabolism in isolated rat skeletal muscle

The lumbrical muscle: a novel in situ system to evaluate adult skeletal muscle proteolysis and anticatabolic drugs for therapeutic purposes

All Three Trimester Binge Alcohol Exposure Causes Fetal Cerebellar Purkinje Cell Loss in the Presence of Maternal Hypercapnea, Acidemia, and Normoxemia: Ovine Model

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