A fully implanted drug delivery system for peripheral nerve blocks in behaving animals

Area of Science:

• Neuroscience
• Animal Models
• Motor Control Research

Background:

• Temporary peripheral nerve inhibition is crucial for studying the nervous system and motor control.
• Permanent lesions in animal models can lead to complications like sores and self-mutilation.
• A method for reversible, controlled motor deficits is needed to avoid these complications.

Purpose of the Study:

• To develop and validate a chronically implanted drug delivery system for temporary peripheral nerve blocks.
• To assess the efficacy of this system in inducing controlled motor deficits in non-human primates and rabbits.
• To determine optimal anesthetic protocols for different animal models.

Main Methods:

• Development of a nerve cuff and subdermal injection dome system for chronic drug delivery.
• Application of the system for median and ulnar nerve blocks in rhesus macaque monkeys.
• Application of the system for sciatic nerve blocks in rabbits.

Main Results:

• The system effectively delivered local anesthetics directly to peripheral nerves for extended periods.
• Median and ulnar nerve blocks in monkeys resulted in over 80% loss of hand and wrist strength.
• Sciatic nerve blocks in rabbits induced ambulatory motor deficits, with epinephrine proving essential for monkeys.

Conclusions:

• The developed drug delivery system enables rapid, repeatable, and controlled induction of temporary motor deficits.
• This method offers a valuable tool for studying the nervous system and motor control adaptations without permanent lesions.
• Anesthetic protocols may need to be tailored, with epinephrine being critical for effective blockade in certain primate models.