Local anesthesia instruments such as materials, which can significantly reduce the excitation of the transition nerves.
Depending on the application site, anesthetics cause various types of anesthesia: terminal.

 Under terminal anesthesia or surface, the material put on the mucosal surface, where the sensitive nerve block galūnėlės. In addition, the anesthetic can be spread on the surface of the damaged or open. In moving anesthesia, the material is introduced into the nerve entrance. Impact occurs through the excitation of nervous fibers blocking, resulting in the disappearance of nerve sensitivity of the area. Other pravedamosios anesthesia is a type of anesthesia to the spinal cord, and then anesthetic affects the front and rear cerebral spinal root cuttings, turning off the lower half of body sensitivity to pain.
In infiltracinei anesthesia, Analgesia išmirkant performed after the layer of tissue in the operative field. In this case, acting anesthetic and sensitive nerve backs and nerve impact.

Local anesthesia is considered the initiator of Russian scientist Vasilii Konstantinovičius Anrepas of 1879, the first time, discovered the cocaine anestezuojančias properties, which intensified the work of chemists. It was then susintetinta many substances in a anestezuojančiu activity, but only a few of them met the requirements for this group.
The main requirements for the local anesthetic:

1. They must have a high degree of exposure nerviniam fabric selection.
2. Not have adverse effects on the body, ie, not adverse, and have low toxicity.
3. When the anesthesia is to quickly reach a sufficient depth and duration, regardless of the anesthetic route.
4. Local anesthetics are well soluble in water and disintegrating them in the storage and sterilization.
5. They have to narrow the blood vessels (at least not to expand them).