Medullary projections of rabbit carotid sinus nerve

In New Zealand white rabbits, cholera-toxin HRP was injected into the carot id sinus nerve just proximal to the carotid sinus. After survival periods o f 3-5 days the rabbits were anesthetized and the brain fixed with aldehyde solution. Transverse sections were cut on a sledge microtome and the sectio ns reacted with the tetramethylbenzidine procedure. HRP-positive fibers ent ered the ipsilateral dorsolateral medulla at the level of the acoustic tube rcle, joining the tractus solitarius. Positive fibres were found principall y ipsilaterally in four regions of the medulla: in the caudal two thirds of the nucleus tractus solitarius, in its dorsolateral regions and, more caud ally, in its commissural subdivision; in the dorsolateral aspect of the spi nal nucleus of the trigeminal nerve; in the region ventral and ventrolatera l to the tractus solitarius (extending beyond the nucleus tractus solitariu s); and in the ventrolateral medulla oblongata. (C) 1999 Elsevier Science B .V. All rights reserved.