Muscle Function Core

Muscle contractile and mechanical measurements:
In-Vivo: Length-torque, torque-frequency, fatigue, work, power, stretch- injury, stiffness analyses, custom designed protocols

In-Vitro: Length-tension, force-frequency, force-velocity, fatigue, work, power, stretch-injury, stiffness analyses, custom designed protocols

In-Vitro and In-Vivo mouse muscle contractile properties

Facilities
In-Vitro: Facilities include Aurora Scientific, Inc. 300B dual mode servomotors that determine a wide range of isometric and isotonic measures from isolated skeletal muscles. Grass, Inc. FT03 isometric transducers obtain isometric contractile properties. We can collect data from four muscles simultaneously, either four muscles from one mouse, or two muscles from each of two mice. Resting tension for muscles on the servomotors and the transducers is automatically maintained by computer-controlled stepper motors.

In-Vivo: Facilities include an Aurora Scientific, Inc. 300C-LR servomotor to determine isometric and dynamic contractile properties of mouse hind limb muscles, and an isoflurane anesthesia system to sedate mice. Mice are easily aroused once isoflurane is removed. This approach to in-vivo contractile assessment permits time course studies to monitor changes in function over time, in the same mice as a function of age, disease, treatment, genetic manipulation, or diet, etc. We can collect data from one limb at a time, or both limbs in a given experiment.

Muscles
In-Vitro: Typical mouse muscles investigated include the extensor digitorum longus (EDL), the soleus, and diaphragm strips. We are open to other suggestions.
In-Vivo: Plantar and dorsi flexor mouse hind limb muscles.

Software
Data collection: Servomotors are controlled by custom software that enable control of electrical stimulation parameters (e.g., duration, frequency, and pulse width) and digital acquisition of both force and displacement responses during static and dynamic muscle contractions. Data from Grass transducers are similarly obtained, except for displacement data.

Data analysis: Data are analyzed by custom software. Data generated can include the temporal and stress generating characteristics of the twitch and tetanic responses; the length-tension relation; stress-frequency relation; the force-velocity relation; power curve; stretch-injury protocols (with or without dye uptake); mechanical properties such as stiffness; and, fatigue properties. Key contractile parameters include Resting Tension, Peak Tension; Time to Peak Tension, ± dF/dt, ½ Relaxation Time, and the Tension-Time Integral (among others). Data are output in digital format to generate publication quality figures (note: if we make the figures, additional charges would apply). (Note: stress is force divided by cross sectional area of the muscle; also known as specific force).

Data Collection/Analysis Protocols: We can use our existing suite of protocols or a custom design protocol (additional charges apply for a custom design).