Participation of cholinergic systems in the bulbar mechanisms of the regulation of breathing.

The reactions of the respiratory muscles of symmetrical intercostals given bi- and unilateral applications of acetylcholine and its antagonists (atropine and spasmolytin) to various segments of the dorsal surface of the medulla oblongata, the entire region of the projection of the respiratory center, primarily its medial or primarily its lateral zones, were studied in rats. A relationship of the effect to the level of activity of cholinergic structures and the localization of the exposure, was identified. The results obtained suggest an uneven distribution of the M and N cholinoreactive systems in homotopic structures of the medulla oblongata. A conclusion was drawn of the undoubted participation of cholinergic mediation in the mechanisms of integration of paired divisions of the bulbar respiratory center and the central regulation of respiration.