BIOL 1260 Lecture 5: Local Anesthetics and ANS
2 Dec 2016
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Document Summary
An agent that interrupts pain impulses in a specific region of the body w/o loss of patient consciousness. Normally, completely reversible: agent doesn"t produce residual effect on nerve fiber. Nociceptor activation (transmit pain info: some receptors transduce stimuli (thermal, mechanical, chemical) into electric potentials. Capsaicin receptor trpv1: heat-activated ion channel of pain pathway, activated in low ec ph, vanilloid chemical ligands like capsaicin, heat. Used by freud to wean a patient from morphine addiction. 1884 first use of injection of cocaine into a sensory nerve trunk to create surgical anesthesia cocaine: prototypical local anesthetic. Coca leaves produce numbing effect on mouth. Procaine/ novocaine: ester-linked local anesthetic: quickly hydrolyzed in plasma by pseudo-cholinesterase, byproducts of metabolism: para-aminobenzoic acid common cause of allergic reactions. Lidocaine: amide-linked local anesthetic: metabolized in liver, far more stable in solution longer duration of action less motor block. Bupivacaine: used for epidural, less motor block mechanism of action.
