Instabilities in the transient response of muscle.
نویسندگان
چکیده
We investigate the isometric transient response of muscle using a quantitative stochastic model of the actomyosin cycle based on the swinging lever-arm hypothesis. We first consider a single pair of filaments, and show that when values of parameters such as the lever-arm displacement and the cross-bridge elasticity are chosen to provide effective energy transduction, the T(2) curve (the tension recovered immediately after a step displacement) displays a region of negative slope. If filament compliance and the discrete nature of the binding sites are taken into account, the negative slope is diminished, but not eliminated. This implies that there is an instability in the dynamics of individual half sarcomeres. However, when the symmetric nature of whole sarcomeres is taken into account, filament rearrangement becomes important during the transient: as tension is recovered, some half sarcomeres lengthen whereas others shorten. This leads to a flat T(2) curve, as observed experimentally. In addition, we investigate the isotonic transient response and show that for a range of parameter values the model displays damped oscillations, as recently observed in experiments on single muscle fibers. We conclude that it is essential to consider the collective dynamics of many sarcomeres, rather than the dynamics of a single pair of filaments, when interpreting the transient response of muscle.
منابع مشابه
Dynamic Analysis and Stability of Articulated Liquid Cargo Vehicles with Tank Baffles
Articulated liquid cargo vehicles transporting inflammable fuels and dangerous chemical products require special consideration when traveling on urban roads or cruising at highway speeds. The road safety and handling of these kinds of vehicles may be adversely affected when negotiating sharp turns or travelling on slippery roads, which may result in either lateral instabilities or complete roll...
متن کاملDynamic Analysis and Stability of Articulated Liquid Cargo Vehicles with Tank Baffles
Articulated liquid cargo vehicles transporting inflammable fuels and dangerous chemical products require special consideration when traveling on urban roads or cruising at highway speeds. The road safety and handling of these kinds of vehicles may be adversely affected when negotiating sharp turns or travelling on slippery roads, which may result in either lateral instabilities or complete roll...
متن کاملTramadol Overdose Induced Transient Paresthesia and Decreased Muscle Strength: A Case Series
Background: Tramadol overdose is relatively common in Iran. A series of tramadol poisoned patients with paresthesia and decreased muscle strength are described. Methods: In this prospective cross-sectional study, all referred cases to Mashhad Medical Toxicology Center with suspected tramadol poisoning between 1st July 2010 and 1st September 2012 were included. Patients with mixed overdose, hist...
متن کاملThe Pharmacological Effects of Odonthobuthus doriae Scorpion Venom and Its Extracted Fractions on Neuro-Muscular Transmission
The effect of Odonthobuthos doriae (O.d) scorpion venom at 0/3, 1 and 3, 10 µg/ml concentrations were investigated on nerve-muscle transmission, using the Twitch tension technique. A concentration of 0.3 µg/ml caused a small change in the twitch height in response to indirect muscle stimulation, but higher concentrations (1, 3, 10 µg/ml) caused a transient augmentation in twitch response follow...
متن کاملThe Pharmacological Effects of Odonthobuthus doriae Scorpion Venom and Its Extracted Fractions on Neuro-Muscular Transmission
The effect of Odonthobuthos doriae (O.d) scorpion venom at 0/3, 1 and 3, 10 µg/ml concentrations were investigated on nerve-muscle transmission, using the Twitch tension technique. A concentration of 0.3 µg/ml caused a small change in the twitch height in response to indirect muscle stimulation, but higher concentrations (1, 3, 10 µg/ml) caused a transient augmentation in twitch response follow...
متن کاملEnhanced expression of transient receptor potential channel 3 in uterine smooth muscle tissues of lipopolysaccharide-induced preterm delivery mice
Objective(s): We aimed to investigate the influence of transient receptor potential channel 3 (TRPC3) on lipopolysaccharide-induced (LPS) preterm delivery mice. Materials and Methods: Mice were randomly assigned to the four groups: an unpregnant group, a mid-pregnancy group (E15), a term delivery group, and an LPS-induced preterm delivery group (intraperitoneal injection LPS at 15 days). Uterin...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Biophysical journal
دوره 85 2 شماره
صفحات -
تاریخ انتشار 2003