ABSTRACT
Measurement of ventilation in AChE/ mice supported the conclusion that the lethal effect of BChE inhibition might result from decreased release of acetylcholine.21 The inspiratory effort (tidal volume) of AChE/ mice increased after AChE inactivation, thus demonstrating increased muscle contraction as a result of accumulated acetylcholine.35 In contrast, the inspiratory effort of AChE/ mice decreased after BChE inactivation, thus demonstrating reduced diaphragm muscle contraction. These opposite effects on respiration indicate that in one case acetylcholine levels increased (in AChE/ mice treated with huperzine A), and in the other case acetylcholine levels decreased (in AChE/ mice treated with bambuterol). This result is incompatible with the idea that BChE substitutes for AChE function in the AChE/ mouse.
