title: A microcapsule technique for long-term conduction block of the sciatic nerve by tetrodotoxin.
abstract: Tetrodotoxin (TTX) is a selective blocker of voltage-gated Na+ channels that is used to block action potentials in vitro and in vivo. Maintaining a sufficiently high local concentration of TTX in vivo to block conduction in a peripheral nerve is technically demanding and carries a risk of systemic toxicity. We report that slow diffusion of TTX out of a microcapsule (glass capillary) inserted beneath the epineurium of the sciatic nerve, with a loose cuff around the nerve, combines high blocking efficacy with low systemic toxicity in rats and mice. The local anaesthesia and motor paralysis was stable for at least 4-6 weeks. The conduction block was reversible and did not cause any obvious nerve injury. Low cost and simple surgical implementation make this new system an interesting alternative to existing long-term drug delivery methods.
authors.affiliation: Department of Physiology, Institute for Basic Medical Sciences, University of Oslo, Box 1103, Blindern, N-0317 Oslo, Norway.
authors.forename: Vladimir N
authors.initials: VN
authors.lastname: Martinov
authors.forename: Arild
authors.initials: A
authors.lastname: Njå
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects / Q000473:pathology; D002214:Capsules; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography / Q000379:methods; D005260:Female; D007839:Functional Laterality; D015918:Infusion Pumps, Implantable; D008297:Male; D051379:Mice; D009407:Nerve Block / Q000379:methods; D009431:Neural Conduction / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D012584:Sciatic Nerve / Q000187:drug effects* / Q000502:physiology; D026941:Sodium Channel Blockers / Q000633:toxicity*; D013779:Tetrodotoxin / Q000633:toxicity*; D013997:Time Factors
chemical_list: D002214:Capsules; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin