Origins of colonic preganglionic parasympathetic motorneurons from the central nervous system: a wheat germ agglutinin- horse radish peroxidase study in the ferret (Mustela putorius furo)

ABSTRACT

The Wheat germ Agglutinin Horseradish Peroxidase (WGA-HRP) transneural nerve tracing technique was used to study the localisation of colonic preganglionic parasympathetic neurons in the central nervous system of the ferret. The entire colon, from the iliocecal junction to the colorectal junction was subdivided into four segments and the muscular wall of each segment injected separately with the tracer. The ferrets used as controls were also subdivided into four groups. The first group was injected with normal saline, the second group was the tracer following bilateral trunkal vagotomy, the third group intraperitoneally and the fourth group had tracer injected into the hepatic portal vein. The experimental as well as control ferrets were allowed to survive for 24 to 96 hours after which they were anaesthetized and perfused sequentially with normal saline, buffered fixative and buffered sucrose. Serial transverse frozen sections were taken from the brainstem and the sacral segments were taken from the spinal cord of the ferrets. These were then processed for WGA-HRP neurohistochemistry and analysed under light and dark illuminations. The results of the study show that the dorsal motor nucleus of the vagua nerve (DMX) supplies the anterior 3 segments of the colon while the sacral segment of the spinal cord supplies the post 2 segments of the colon.