[Establishment of somato-sympathetic reactions during the early stages of postnatal ontogeny in cats].

In adult cats and 1--16--day kittens, repeated stimuli of less than 1/sec and supramaximal strength applied to afferent fibers of nervus ischiadicus evoked the multicomponent responses recorded from efferent fibers of n. hypogastricus. Latencies of responses components decreased during postnatal development. In all the animals basic three responses remained unchanged after Th10-12 chordotomy. Stimulation of kittens afferent somatic fibers with frequency of 10/sec and of variable strength enhanced the sympathetic nerve activity and in rare occasions suppressed it. In adult animals the sign of sympathetic nerve response depended on the level of spontaneous sympathetic activity and on the stimulus strength. This relation remained unchanged after the chordotomy. In chordotomised kittens repeated stimuli applied to somatic nerve produced the sympathetic nerve activation alone.