ISSN:
1432-2013
Keywords:
Key words Load-dependent relaxation
;
Diastolic function
;
Length perturbation
;
Cardiac muscle
;
Cross-bridge cycle
;
Diastolic vibration
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Applying external mechanical vibration during the relaxation phase of rat papillary muscle decreases the duration of the first part of the relaxation phase. To elucidate the basic mechanism responsible for this shortening of the relaxation period, we applied a controlled vibration to isolated twitching rat papillary muscles during various phases in the relaxation of a twitch. The first part of the relaxation phase was accelerated when length perturbations were applied in the first part of the relaxation of a twitch, dependent on both amplitude and frequency of the perturbation. When vibrations were applied in the first half of the relaxation, the second phase of relaxation was slightly slower (about 20%), but when no vibrations were applied in the first phase, relaxation could be accelerated by applying vibration in the latter half of the relaxation phase. Thus, in the latter half of relaxation, the acceleration of relaxation depended upon perturbation events earlier during that twitch. This study indicates that vibration-induced acceleration of relaxation is due (at least in part) to an apparent increase in detachment rate of attached cross-bridges from the thin filament without substantial reattachment.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004240050467
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