The Role of Cholinergic Transmission in the Respiratory Center,

A number of tertiary cholinolytics, which were administered intravenously, induced continuous discharges of impulses in the phrenic nerve and cessation of inhalation. All of these substances induce apnea in identical doses. There is no correspondence between the effect and the strength of the cholinolytic activity of the substances. Other tertiary cholinolytics under the same conditions do not induce inspiratory apnea. Intravenous administration of nicotine up to 100 mgkg does not induce essential disruptions of impulsation of the phrenic nerve. Arecoline up to 3.0 mgkg induces reduction of rhythm, it disrupts the equilibrium of breathing movements, and it decreases the amplitude of the action potentials of the phrenic nerve APPN. Severing of the vagus nerves, denervation of the sinocarotid zones, and severing of the brain stem in the quadrigeminal and pons area do not essentially change the effect of cholinolytics and cholinomimetics on the APPN.