Tension responses to sudden length change in stimulated frog muscle fibres near slack length
Population
Isolated muscle fibres about 6 mm long from the anterior tibial muscle of Rana temporaria
Design
Preclinical
Authors
Discussion
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Implication
Challenges two-component muscle models in amphibians; leaves open relevance to mammalian cardiac sarcomere mechanics.
Key Points
- This research investigates how isolated frog muscle fibres respond to sudden changes in length during stimulation.
- Applied step changes in length to isolated muscle fibres from Rana temporaria during tetanic stimulation.
- Measured tension response phases using a high-frequency force transducer and eliminated tendon compliance effects.
- Analyzed recovery patterns and compliance characteristics at various temperatures.
- Initial tension change occurred synchronously with length change, indicating almost linear compliance (4 nm per half-sarcomere to zero tension).
- During phase 2, tension recovery was influenced by step amplitude, with larger shortens leading to reduced tension levels.
- An increase in temperature raised both developed tension and stiffness, altering the required shortening to achieve zero tension.
Structured PICO
P
Population
Isolated muscle fibres about 6 mm long from the anterior tibial muscle of Rana temporaria
I
Intervention
Step change of length (stretches and releases) during tetanic stimulation
O
Outcome
Tension response to sudden length change
Stimulated frog muscle fibres exhibit a rapid, almost linear and undamped compliance in response to sudden length changes, followed by a multi-phasic tension recovery.
Cite This Study
Ford et al. (1977) studied this question.