A local anesthetic is a drug that causes reversible local anesthesia, generally for the aim of having a local analgesic effect that is, inducing absence of pain sensation, although other local senses are often affected as well. Also, when it is used on specific nerve pathways, paralysis can be achieved as well. All local anesthetics are membrane stabilizing drugs; they reversibly decrease the rate of depolarization and repolarization of excitable membranes. Though many other drugs also have membrane stabilizing properties, not all are used as local anesthetics. Local anesthetic drugs act mainly by inhibiting sodium influx through sodium-specific ion channels in the neuronal cell membrane, in particular the so-called voltage-gated sodium channels. When the influx of sodium is interrupted, an action potential cannot arise and signal conduction is inhibited. The receptor site is thought to be located at the cytoplasmic portion of the sodium channel. Local anesthetic drugs bind more readily to sodium channels in an activated state, thus onset of neuronal blockade is faster in neurons that are rapidly firing. This is referred to as state dependent blockade. Local anesthetics can block almost every nerve between the peripheral nerve endings and the central nervous system. The most peripheral technique is topical anesthesia to the skin or other body surface. Small and large peripheral nerves can be anesthetized individually or in anatomic nerve bundles. Spinal anesthesia and epidural anesthesia merges into the central nervous system.
A journal is a periodical publication intended to further progress of science, usually by reporting new research. Most journals are highly specialized, although some of the oldest journals publish articles, reviews, editorials, short communications, letters, and scientific papers across a wide range of scientific fields. Journals contain articles that peer reviewed, in an attempt to ensure that articles meet the journal's standards of quality, and scientific validity. Each such journal article becomes part of the permanent scientific record.
Last date updated on June, 2014