BMS 450 Lecture Notes - Tracheal Intubation, Flaccid Paralysis, Neuromuscular Junction
Document Summary
Amazon basin natives: arrows poisoned by extract from vine c. tomentosum caused a curious flaccid paralysis; api d-tubocurare. Claude bernard (first lectures in western pharmacology); college de france, founded. Stimulation of nerve did not cause muscle contraction. Ionic; generally devoid of cns effects; edible d-tubocarine chloride (historical, not much used) 3 min half-life; rapid tracheal intubation in trauma. Nerve gas binds to acetylcholinesterase excess of ach. Lou gehrig"s or amyotrophic lateral sclerosis (als) death of spinal motor. Strichnine competes at glycine r in spinal cord. Achr: 2 alpha, beta, delta, and gamma subunits. Alpha has binding sites for ach, nmj blockers, bungarotoxin (irreversible binding), nicotine. Open state: na+ enters cell, k+ exits, low affinity for ach. Graded receptor potential must reach threshold to fire muscle action potential; ca++ release from sr. Only 25% of achr need to be occupied by ach for full response. >75% of receptors need to be bound by agent for onset of antagonism (flaccid paralysis)
