Biochemical changes in progressive muscular dystrophy. XI. Cyclic nucleotides in the skeletal and cardiac muscle of normal and dystrophic mice

1981 ◽  
Vol 59 (4) ◽  
pp. 329-334 ◽  
Author(s):  
Uma Srivastava ◽  
Mikael Sebag ◽  
Manohar Thakur

cAMP and cGMP contents were determined in the skeletal and cardiac muscle of normal and dystrophic mice. cAMP content increased in the dystrophic muscle at every stage of the disease whereas cGMP content decreased in the preliminary stages and increased at the terminal stage of the disease. The content of both nucleotides per heart was not affected in murine dystrophy. Thus, levels of cyclic nucleotides appear to be selectively altered in dystrophic skeletal muscle.

1986 ◽  
Vol 64 (12) ◽  
pp. 1339-1348 ◽  
Author(s):  
Manohar Thakur ◽  
Mikael Sebag ◽  
Uma Srivastava

Concentrations of cAMP and cGMP were measured (per milligram DNA) in the lymphoid (thymus, spleen) and nonlymphoid organs (liver, brain, kidney, lungs, heart, pancreas, skeletal muscle, lens) of normal (+/+) and dystrophic (dy/dy) 129 ReJ mice aged 30, 60, and 90 days. The cAMP concentrations in the thymus did not reveal any significant differences at 30 and 60 days of dystrophy, but were considerably higher (2-fold) at 90 days. cGMP concentrations were decreased in the thymus at 30 days (0.20-fold) and markedly elevated at 60 (2-fold) and 90 days (3-fold) of the disease. The [cAMP]/[cGMP] ratio was increased (1.30-fold) at 30 days of dystrophy, and this was followed by a sharp decline at 60 days (2-fold), with a lesser decrease at 90 days (0.34-fold). In the spleen, the cAMP concentrations were augmented significantly in all stages of dystrophy (1.5- to 2.6-fold). cGMP (per milligram DNA) did not show any significant variation at 30 and 60 days of the disease but was increased (3-fold) at 90 days. The [cAMP]/[cGMP] ratio, which was enhanced in the spleen at 30 (2-fold) and 60 days (1.5-fold), demonstrated no change at 90 days of dystrophy. These results indicated significant differences in the concentration of cyclic nucleotides and their ratios in the thymus and spleen of 129 ReJ dy/dy mice. The modifications were not limited to lymphoid organs alone, having been noted in the nonlymphoid organs as well. These changes could, in turn, influence immune responsiveness and could cause immunodepression in dystrophic mice.


1972 ◽  
Vol 50 (4) ◽  
pp. 409-415 ◽  
Author(s):  
Uma Srivastava

The synthesis of native myosin, actin, and tropomyosin in the skeletal muscle of normal and hereditary dystrophic mice was studied with the help of direct counting as well as acrylamide-gel electrophoresis and protein purification procedures.Labelling of the nascent protein indicated that heavier polysomes from the normal muscle were able to incorporate more radioactivity into the protein than the heavier polysomes from the dystrophic muscles. Contrary to this, lighter polysomes in the dystrophic muscle demonstrated higher incorporation as compared to the normal.Results of in vivo and in vitro incorporation as well as those of acrylamide-gel electrophoresis and protein purification procedures indicated that synthesis of myosin decreased in the dystrophic muscle. The synthesis of actin did not show a significant change either in normal or dystrophic muscle, whereas that of tropomyosin increased sharply in the dystrophic mouse muscle.


1967 ◽  
Vol 45 (9) ◽  
pp. 1419-1425 ◽  
Author(s):  
Uma Srivastava

Normal and dystrophic mice were injected intravenously with uridine-2-14C at various stages of the disease. Radioactivity in the acid-soluble fraction of most of the tissues studied was unchanged or not significantly different in dystrophic animals. In vivo incorporation of uridine-2-14C into RNA increased in dystrophic muscle as compared to normal muscle at 30 days, remained the same at 60 days, and was reduced at 90 days. Similar results were also observed on the in vitro incorporation of uridine-2-14C catalyzed by homogenates of normal and dystrophic muscle. Dystrophic brain and pancreas showed a decrease in the incorporation at each stage investigated as compared to controls. No change in the incorporation was noted in dystrophic and normal liver, kidney, spleen, and heart. The decrease in uridine-2-14C incorporation in dystrophic muscle at 90 days could be due to an increased RNA content. Such a phenomenon was explained as due to infiltration of dystrophic muscle by invading macrophages.It is concluded that the metabolism of RNA is not decreased in the dystrophic muscle in preliminary stages of the disease as compared to the control.


1959 ◽  
Vol 197 (2) ◽  
pp. 487-490 ◽  
Author(s):  
Ho Lee Young ◽  
Wei Young ◽  
Isidore S. Edelman

Skeletal and cardiac muscle from strain 129 mice with hereditary muscular dystrophy and from their normal littermates were analyzed for sodium, potassium, total lipids and the separate lipid components. Dystrophic skeletal muscle contained 12–23% less potassium and 68–107% more sodium than the normal anatomical counterparts when referred to fat-free dry weight. Cardiac muscle from dystrophic mice did not differ from the normal in potassium content and had only 20% more total lipid. Fat content was substantially greater in dystrophic skeletal muscle than in normal muscle by the following percentages: 92% for total lipids, 168% for triglycerides, 140% for total cholesterol and 87% for nonesterified fatty acids assayed by infrared analysis. The phospholipid content of dystrophic and normal skeletal muscle, however, was approximately the same. The lack of information concerning interstitial connective tissue content of these tissues bars any precise interpretation of the electrolyte or lipid changes in this genetic myopathy.


1977 ◽  
Vol 168 (2) ◽  
pp. 229-237 ◽  
Author(s):  
T A de Kretser ◽  
B G Livett

1. Mouse skeletal-muscle sarcolemma was isolated, and the preparations obtained from normal mouse muscle and from muscle of mice with hereditary muscular dystrophy were characterized with respect to appearance under the optical and electron microscopes, distribution of marker enzymes, histochemical properties and biochemical composition. 2. The sarcolemmal membranes from normal and dystrophic muscle were subjected to detailed lipied analysis. Total lipid content was shown to increase in sarcolemma from dystrophic mice as a result of a large increase in neutral lipid and a smaller increase in total phospholipids. Further analysis of the neutral-lipid fraction showed that total acylglycerols increased 6-fold, non-esterified fatty acid 4-fold and cholesterol esters 2-fold, whereas the amount of free cholesterol remained unchanged in sarcolemma from dystrophic muscle. Significant increases were found in lysophosphatidylcholine, phosphatidylcholine and phosphatidylethanolamine in dystrophic-muscle sarcolemma; however, the relative composition of the phospholipid fraction remained essentially the same as in the normal case. 3. The overall result of alterations in lipid composition of the sarcolemma in mouse muscular dystrophy was an increase in neutral lipid compared with total phospholipid, and a 4-fold decrease in the relative amount of free cholesterol in the membrane. The possible impact of these changes on membrane function is discussed.


1993 ◽  
Vol 265 (1) ◽  
pp. C47-C53 ◽  
Author(s):  
T. G. Kokate ◽  
J. A. Heiny ◽  
N. Sperelakis

The effects of adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) on slow calcium currents (ICa) were investigated using the Vaseline-gap voltage-clamp technique in bullfrog skeletal muscle cut fibers. Both cAMP and cGMP induced a pronounced increase in the amplitude of ICa when applied to the cut ends of fibers. Both cyclic nucleotides also decreased time to peak current at all membrane potentials. The current-voltage relationship was shifted toward more negative potentials by cAMP as well as cGMP. The potentiating effects of cAMP and cGMP on ICa were additive. 8-Bromo analogues of both nucleotides had similar effects on ICa. The beta-adrenergic agonist isoproterenol, applied extracellularly, also produced an increase in the amplitude of ICa and produced a leftward shift in the current-voltage relationship. These results suggest that both cAMP and cGMP modulate calcium slow channels in bullfrog skeletal muscle fibers, causing stimulation of the ICa. The effect of cyclic nucleotides on ICa in bullfrog skeletal muscle contrasts with that in mammalian cardiac muscle, in which the same nucleotides produce opposite effects on the slow ICa, i.e., in cardiac muscle cAMP stimulates, and cGMP inhibits, the slow ICa.


1963 ◽  
Vol 205 (5) ◽  
pp. 897-901 ◽  
Author(s):  
Marilyn W. McCaman

The activities of 20 enzymes in normal, heterozygous, and dystrophic mouse muscle were studied by means of quantitative microchemical methods. Enzyme activities in normal and heterozygous muscle were essentially the same. In dystrophic muscle glucose-6-P dehydrogenase, 6-P-gluconic dehydrogenase, glutathione reductase, peptidase, ß-glucuronidase, and glucokinase activities were significantly higher than in normal muscle, while α-glycero-P dehydrogenase and lactic dehydrogenase activities were significantly lower. The pattern of enzyme activities found in normal gastrocnemius denervated by nerve section was strikingly similar to that in dystrophic muscle.


2002 ◽  
Vol 92 (2) ◽  
pp. 435-445 ◽  
Author(s):  
Kevin Culligan ◽  
Niamh Banville ◽  
Paul Dowling ◽  
Kay Ohlendieck

Although the reduction in dystrophin-associated glycoproteins is the primary pathophysiological consequence of the deficiency in dystrophin, little is known about the secondary abnormalities leading to x-linked muscular dystrophy. As abnormal Ca2+ handling may be involved in myonecrosis, we investigated the fate of key Ca2+ regulatory membrane proteins in dystrophic mdx skeletal muscle membranes. Whereas the expression of the ryanodine receptor, the dihydropyridine receptor, the Ca2+-ATPase, and calsequestrin was not affected, a drastic decline in calsequestrin-like proteins of 150–220 kDa was observed in dystrophic microsomes using one-dimensional immunoblotting, two-dimensional immunoblotting with isoelectric focusing, diagonal two-dimensional blotting technique, and immunoprecipitation. In analogy, overall Ca2+ binding was reduced in the sarcoplasmic reticulum of dystrophic muscle. The reduction in Ca2+ binding proteins might be directly involved in triggering impaired Ca2+ sequestration within the lumen of the sarcoplasmic reticulum. Thus disturbed sarcolemmal Ca2+ fluxes seem to influence overall Ca2+homeostasis, resulting in distinct changes in the expression profile of a subset of Ca2+ handling proteins, which might be an important factor in the progressive functional decline of dystrophic muscle fibers.


1991 ◽  
Vol 260 (5) ◽  
pp. G764-G769 ◽  
Author(s):  
S. Rattan ◽  
C. Moummi ◽  
S. Chakder

This investigation examined and compared the role of cyclic nucleotides in the mediation of internal anal sphincter (IAS) relaxation caused by the addition of neuropeptide calcitonin gene-related peptide (CGRP) and atrial natriuretic factor (ANF). The studies were performed in vitro on smooth muscle strips of opossum IAS. The relaxation produced by CGRP and ANF was examined before and after the addition of tetrodotoxin (TTX) (1 x 10(-6)M). At this concentration, TTX did not have any significant effect on the relaxation produced by either CGRP or ANF, suggesting that these peptides act directly on the smooth muscle. Addition of CGRP (3 x 10(-6) M) produced the maximal relaxation and significantly increased cAMP content without changing cGMP. On the other hand, addition of ANF (3 x 10(-6) M) caused a similar fall in IAS tension that was accompanied by a significant elevation in cGMP without any change in cAMP content. The rises in the levels of cyclic nucleotides preceded the onset of fall in the resting tension of IAS. Our results demonstrate that CGRP and ANF relax isolated strips of opossum IAS by their action directly at the smooth muscle and that this relaxation is associated with an increase in cAMP and cGMP, respectively. The studies suggest the presence of both cAMP and cGMP pathways in the IAS and that the relaxation of IAS smooth muscle in response to different peptides may occur via a specific intracellular biochemical pathway.


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