Blockade of nerve conduction by a local anesthetic is characterized by:
Essentials of medical pharmacology, seventh edition , page no=361, Local anaesthetics block nerve conduction by decreasing the entry of sodium ions during upstroke of action potential. They interact with a receptor situated within the voltage sentive sodium channel and raise the threshold of channel opening. Hence optuon 2 is the answer since they have to cross the cell membrane to block the nerves.
Greater potential to block a resting nerve as compared to a stimulated nerve
Need to cross the cell membrane to produce the block
Large myelinated fibers are blocked before the un myelinated fibers
Cause consistent change of resting membrane potential
Anesthesia