Neuron number in the myenteric plexus of the ascending colon of rats. A comparative study using two staining techniques.

We carried out this study with the purpose of comparing the neuronal density in antimesocolic and intermediate regions of the colon of rats. We used the ascending colon of ten seven-months old Wistar rats. With the Giemsa method we found 29,046 neurons/cm2 on the antimesocolic region and 30,968 neurons/cm2 on the intermediate regions. With the NADH-diaphorase technique 12,308 neurons/cm2 on the antimesocolic regions and 8798 neurons/cm2 on the intermediate regions were evidenced. The number of NADH-diaphorase positive neurons is significantly less than the number of Giemsa-stained neurons and that this difference is enhanced on the intermediate regions of the intestinal circumference. Therefore, to compare the number of neurons of an intestinal segment of a same species at the same age, it is necessary to take into consideration the technique employed and the region of the intestinal circumference from where the sample was obtained.