PHAR3818 Lecture Notes - Lecture 23: Sodium Channel, Local Anesthetic, Central Nervous System
23 Jul 2018
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Anaesthesia is a loss of sensation, with or without the loss of consciousness. Accordingly, a wide range of drugs with a diverse range of chemical structures are anaesthetics including: Central nervous system depressants e. g. analgesics, barbiturates, benzodiazepines. A local anaesthetic is any drug, which causes a reversible abolition of sensation or pain in a part of the body without loss of consciousness. They bind to selective site(s) on the voltage-gated sodium channel in the excitable membranes. By reducing sodium passage through channels, local anaesthetics interfere with action potentials. Reversibly block the nerve conductance that transmit the feeling of pain to the brain. Electrophysiology of the nervous system: nerves have resting membrane potentials of ~70-90 mv as a result of slight imbalance of electrolytes across the nerve membrane (i. e. between the intracellular and the extracellular compartments) Inside the cell (intracellular): an-, organic molecule (such as protein), k: outside the cell (extracellular): cl-, na+
