Effects of Morphine and Physostigmine on the Ventilatory Response to Carbon Dioxide

Abstract

Because morphine diminishes the Sc and Sp of the chemoreflex loop to the same extent this depressant effect is presumably due to an action on the respiratory integrating centers rather than on the peripheral and central chemoreceptors as such and is not antagonized by physostigmine. We argue that the increase in B may be due to changes in the amount of acetylcholine available in the brain and can be antagonized by physostigmine.