An implantable nerve cooler for the exercising dog

Area of Science:

• Physiology
• Biomedical Engineering
• Surgical Devices

Background:

• Cervical vago-sympathetic activity influences physiological responses during exercise.
• Reversible modulation of nerve activity is crucial for physiological research and therapeutic applications.

Purpose of the Study:

• To construct and evaluate an implantable nerve cooler for reversible blockade of cervical vago-sympathetic activity.
• To assess the device's efficacy in controlling nerve temperature and blocking nerve activity in exercising dogs.

Main Methods:

• An implantable gilt brass container was used, perfused with cooled alcohol via silicone tubes.
• An electromagnetic valve controlled alcohol flow to maintain target nerve temperature, measured by a thermistor.
• The device was tested in exercising dogs, monitoring heart rate changes to confirm vagal block.

Main Results:

• The nerve cooler achieved reversible blockade of cervical vago-sympathetic activity.
• Complete vagal block was obtained at a nerve temperature of 2°C within 50 seconds.
• Nerve temperature was precisely controlled during exercise (variation < 0.5°C) and the device showed reusability after 2 weeks.

Conclusions:

• The implantable nerve cooler is an effective tool for reversibly blocking cervical vago-sympathetic activity.
• The device allows for precise temperature control and rapid nerve blockade, suitable for physiological studies in exercising animals.
• The construct is durable and reusable, indicating potential for long-term applications.