CLASSIFICATION OF THE ENTERIC NERVE-CELLS OF THE PORCINE SMALL-INTESTINE INTO 2 SUBPOPULATIONS USING ENZYME-HISTOCHEMICAL TECHNIQUES

Using acetylcholinesterase (AChE), nicotinamide adenine dinucleotide d iaphorase (NADHd), and nicotinamide adenine dinucleotide phosphate dia phorase (NADPHd) enzyme histochemical techniques, the ganglionated ple xuses of the porcine enteric nervous system were investigated in small intestine whole-mount preparations. Both AchE and NADHd techniques re vealed a majority of the neurons in the ganglia of all three major ple xuses. The AchE technique also demonstrated clearly the axodendritic n etworks of the plexus myentericus. Intraganglionic blank areas reveale d the localization of negative cell groups. A very high correlation wa s found between the activity of both enzymes in one neuron, although t his correlation was certainly not linear. Many neurons exhibited a str onger signal for one enzyme. A very small part of the positive nerve c ells showed intense staining for both AchE and NADHd. The NADPHd techn ique demonstrated that the NADPHd-positive neurons fill the negative i ntraganglionic spaces in the ganglia. Double staining with the two oth er enzymes showed virtually no colocalization of NADPHd with either NA DHd or AchE in the porcine jejunal enteric ganglia. Little negative in traganglionic spaces were seldom found, leaving room for perhaps still more negative enteric neurons. Based upon these results we suggest th at the enteric neurons of the porcine small intestine can be subdivide d into AchE-NADHd and NADPHd subpopulations. Since the latter colocali zes with the neuronal NO synthase enzyme, we further suggest a subdivi sion of the enteric nerve cells into AchE-NADHd and NOS-NADHd neurons. (C) 1994 Wiley-Liss, Inc.