Evidence of collateralization of vagal efferents innervating subdiaphragmatic segments of the gastrointestinal tract in the rat using the double labelling fluorescent dyes technique

ABSTRACT

Collateralization of the abdominal vagal trunks was investigated in the rat using double labelling fluorescence dye technique. A total of 20 adult male and female rats were used for the study. The anterior and posterior walls of the corpus and fundus of the stomach were injected with 0.1 microliter (microliter) of 5 aqueous solution of diamidino yellow (Dy) in eight rats. The same quantity and percentage of fast blue (Fb) was injected into the walls of the duodenum and proximal jejunum in the same eight rats that were injected with Dy. The anterior and posterior walls of the stomach of four rats were injected with 0.1 microliter of 5 Dy only while four other rats had injections of 0.1 microliter of Fb only into the duodenum and proximal jejunum. Two control rats had stomach injections with normal saline, and two rats had saline injections into the intestine. Each rat was perfused with a preservative 14 days after injection and serial sections taken for examination with a fluorescence microscope. The results of the experiment revealed that in the eight rats injected simultaneously with Dy and Fb, some neurons of the dorsal motor nucleus of the vagus nerve (DMX) were labelled with Dy only, some with Fb only and some were doubly labelled with Dy and Fb. No double-labelled neurons were seen in the rat injected with one dye only and no labellings at all were seen in the controls. The pattern of labelling obtained in the study is suggestive of collateralization of axons of the abdominal vagal trunks