[Neuronal organization of the sympathetic system-activating structures of the ventro-lateral surface of the medulla oblongata].

In anesthetized cats, activating effects of the bulbar ventro-lateral surface (BVLS) upon the spinal sympathetic neurons were shown to be transmitted via output sympathoactivating neurons (OSN) with descending axons. Antidromic discharge of these neurons elicited by stimulation of the spinal dorso-lateral funiculus were found in the intermediate zone of the BVLS at the depth of about 400-2000 mu. Stimuli applied to different regions of the BVLS activate at least two groups of surface fibers (conducting velocities 6.7-8.0 and 2-3.2 m/sec) which in their turn activate OSN with a delay of about 20 msec. The mechanism of the delay formation seems to be concentrated in the intermediate zone and formed, probably, by a chain of interneurons. A possible scheme of neuronal organization of the sympathoactivating BVLS structure is discussed.