Effects of denervation on the contents of cholesterol and membrane systems involved in muscle contraction in rabbit fast-twitch sarcotubular system.
Denervated fast-twitch rabbit muscles were progressively losing their fresh weight and the yield of sarcotubular protein was increasing. The activity of Ca(2+)-ATPase was affected but very slightly, the basal Mg(2+)-ATPase and the Mg(2+)-ATPase/Ca(2+)-ATPase ratio however increased together with a simultaneous depression of the membrane-bound acetylcholinesterase activity. We did not observe any differences in density properties of sarcotubular fractions between control and denervated muscle. However, a relative enrichment in SM and H fraction could be seen after denervation with small changes in the content of the Ca(2+)-pump protein, increased levels of calsequestrin and cholesterol, mostly in the heavy and the SM fraction. After denervation the binding sites for 3H-PN-200-110 did not show any changes in receptor affinity, but the number of putative Ca(2+)-channels increased twice along with a depression of 3H-ouabain binding sites. We suggest that the denervation of fast-twitch muscle leads to the hypertrophy of the junctional sarcoplasmic reticulum and the T-system. Changes in the cholesterol content, in the number of putative Ca(2+)-channels and in Na+, K(+)-ATPase can affect the muscle contraction.
Lehotský
J
J
Department of Biochemistry, Comenius University, Medical School, Martin, Czechoslovakia.
Drgová
A
A
Dobrota
D
D
Mézesová
V
V
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002155:Calsequestrin / Q000032:analysis; D005591:Chemical Fractionation; D002784:Cholesterol / Q000032:analysis*; D004095:Dihydropyridines / Q000378:metabolism / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D008297:Male; D009119:Muscle Contraction; D009121:Muscle Denervation; D009132:Muscles / Q000737:chemistry / Q000294:innervation* / Q000648:ultrastructure; D009929:Organ Size; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
D002155:Calsequestrin; D004095:Dihydropyridines; C038806:1,4-dihydropyridine; D002784:Cholesterol; D000110:Acetylcholinesterase; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase