Contractility in Mammalian Heart MuscleCALCIUM AND OSMOLALITY
作者:
Mark Goethals,
Simone Adèle,
Dirk Brutsaert,
期刊:
Circulation Research
(OVID Available online 1975)
卷期:
Volume 36,
issue 1
页码: 27-33
ISSN:0009-7330
年代: 1975
出版商: OVID
关键词: force-velocity-lenglh relation;cat papillary muscle maximum unloaded velocity of shortening;sucrose;NaCl zero load clamp
数据来源: OVID
摘要:
The influence of osmolality of the external medium on the calcium (Ca) dependency of contractility of isolated electrically excited cat papillary muscle was examined. Maximum unloaded velocity of shortening was directly measured by load clamping the muscle from the preload (at the length, Lmax, at which maximum active tension was developed) to zero load (zero load clamp). Peak velocity of shortening at the Lmaxpreload, peak total force, peak rate of force development, time to peak force, and time to half relaxation were also recorded. The performance-Ca response curves (Ca concentration between 1.25 nM and 10 nM) for maximum unloaded velocity of shortening, peak shortening velocity at Lmaxpreload, total force, and peak rate of force development were shifted to the left when osmolality was increased (from 290 mosmoles to 410 mosmoles) with sucrose, and to the right when osmolality was increased with NaCl. The sensitivity for Ca, as determined from the slopes of these response curves, appeared essentially unaltered by either sucrose or NaCl, except for the high Ca concentrations (above 5 mM) at the higher osmolalities (above 370 mosmoles) especially with sucrose.
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