Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The patterns of myosin isoenzymes in fast- and slow-twitch muscles of the rat hindlimb were studied, by pyrophosphate/polyacrylamide-gel electrophoresis, with hypertrophy (induced by synergist removal) and with spontaneous running exercise of 4 and 11 weeks duration. At 11 weeks, changes with hypertrophy in the slow-twitch soleus, composed of greater than 95% SM2 (slow myosin 2) in normal muscles, were minor, and consisted of an increase in the SM1 and SM1', and a loss of intermediate myosin (IM), an isoenzyme characteristic of Type IIa fibres [Fitzsimons & Hoh (1983) J. Physiol. (London) 343, 539-550]. The changes were dramatic, however, in the fast-twitch plantaris muscle. There was a 3-fold increase in the proportion of SM. In addition, IM became the predominant isoenzyme in the profile of hypertrophied plantaris by 4 weeks. These increases were balanced by decreases in the proportion of FM2 (fast myosin 2), with FM1 completely absent from the profile at 11 weeks. The changes in the plantaris with exercise were similar in direction but not as extensive as those with hypertrophy, and FM1 remained present at control levels throughout the study. When hypertrophy and exercise were combined, the increase in slow myosin was equal to the sum of the increases with each treatment alone. Changes at 4 weeks were intermediate between those of control and 11-week muscles. Peptide mapping of individual myosin isoenzymes showed that the heavy chains of IM were different from either fast or slow heavy chains. Furthermore, IM was found to be composed of a mixture of fast and slow light chains. These changes suggest that a transformation of myosin from fast to slow isoforms was in progress in the plantaris in response to hypertrophy, via a Type-IIa-myosin (IM) intermediate stage, a phenomenon similar to that occurring in chronically stimulated fast muscles during fast-to-slow transformation [Brown, Salmons & Whalen (1983) J. Biol. Chem. 258, 14686-14692].
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PMID:Changes in skeletal-muscle myosin isoenzymes with hypertrophy and exercise. 294 96

Vascular mechanical and contractile properties were compared in adult (6 months old) and very-aged (36 months old) Fischer 344/NNiaHSd X Brown Norway/BiNia (F344/NXBN) rats. Our previous work has indicated that aging is associated with aortic medial thickening. This morphological alteration was accompanied by a leftward shift in the aortic stress/strain curve indicating increased vessel stiffness in very-aged animals. Disruption of the endothelium as well as pretreatment of tissues with the nitric oxide (NO) donor sodium nitroprusside eliminated differences, suggesting a link between deficient endothelial NO release and reduced compliance in very-aged aortae. In addition, the Rho kinase inhibitor Y-27632 increased vessel compliance in both adult and very-aged tissues suggesting that the Rho cascade contributed to the stress/strain relationship. Maximal force developed in response to high potassium (K(+)) was reduced by approximately 70% in intact and endothelium-denuded aortae from very-aged rats. In contrast to contractile force development, calcium-dependent stress relaxation was increased in very-aged aorta. Finally, gel electrophoresis indicated a significantly higher tissue content of myosin heavy chain and a higher ratio of SM1/SM2 isoforms with aging. The results suggest multiple molecular changes with aging, which may be expected to alter vascular tissue function.
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PMID:Aging alters mechanical and contractile properties of the Fisher 344/Nnia X Norway/Binia rat aorta. 1716 81