What is the mechanism of action of ester local anesthetics?

The mechanism of action of ester local anesthetics involves inhibiting the conduction of nerve impulses by binding to sodium channels. When local anesthetics are administered, they diffuse across the nerve membrane and bind to the intracellular side of voltage-gated sodium channels. This binding prevents sodium ions from entering the nerve cell during depolarization, effectively blocking the initiation and propagation of action potentials along the nerve fibers. As a result, the transmission of pain signals is disrupted, leading to the desired anesthetic effect.

Ester local anesthetics are characterized by their chemical structure, which includes an ester linkage, but their functional activity is primarily due to their ability to interfere with sodium channel functionality. This blockade leads to a reduction in the excitability of nerve fibers, particularly those responsible for transmitting pain sensations. The onset of anesthesia is contingent upon the concentration of the local anesthetic, the pH of the surrounding tissue, and the specific sodium channels present in the nerve fibers. This mechanism is essential for achieving effective local anesthesia during surgical procedures and pain management.