THE EFFECTS OF SARIN AND ATROPINE ON THE RESPIRATORY CENTER AND NEUROMUSCULAR JUNCTIONS OF THE RAT

Abstract

Records were made of the contractions of a slip of diaphragm muscle which was isolated from the circulation of the rat, while the nerve supply was preserved. Simultaneous records were also made of the contractions of the opposite (circulated) hemidiaphragm, of respiratory rate, of the Hering-Breuer reflex, and of contractions of the gastrocnemius muscle in response to stimulation of the sciatic nerve.Low doses of sarin caused immediate respiratory arrest, purely central in origin; respiration was restored to normal at once when a large dose of atropine was given. When atropine was injected before sarin, much higher doses of sarin were required to depress the respiration, and now the respiratory paralysis took place at the neuromuscular junctions in the diaphragm, the respiratory center remaining relatively unaffected. It was concluded that respiratory paralysis by sarin could be purely central, purely peripheral, or both central and peripheral, depending on the doses of sarin and atropine employed.