A 52-year-old woman was injected with a local anesthetic before the tooth extraction. What mechanism of action underlies the analgesic effect of this drug?

Answer options

1. Disrupted isolated conduction of excitation in the nerve fibers
2. Disrupted physiological intactness of the nerve fibers
3. Disrupted anatomical intactness of the nerve fibers
4. Disrupted axonal transport in the nerve fibers
5. Disrupted functioning of microtubules in the nerve fibers