Related Experiment Videos
Nitric oxide producing neurons in the monkey and human digestive system
R De Giorgio1, J E Parodi, N C Brecha
1CURE/UCLA Digestive Diseases Center, UCLA School of Medicine.
The Journal of Comparative Neurology
|April 22, 1994
Summary
Nitric oxide, produced by nitric-oxide synthase, is found in neurons throughout the digestive system, gallbladder, and pancreas. This neurotransmitter plays a key role in muscle relaxation and vasodilation in these organs.
Area of Science:
- Neuroscience
- Gastroenterology
- Histochemistry
Background:
- Nitric oxide (NO) is a proposed inhibitory neurotransmitter.
- NO is implicated in gastrointestinal muscle relaxation and vasodilation.
Purpose of the Study:
- To map the distribution of NO-producing neurons in the monkey and human digestive system.
- To visualize neuronal nitric-oxide synthase (NOS) using NADPH-diaphorase histochemistry.
Main Methods:
- Nicotinamide-adenine-dinucleotide-phosphate-diaphorase (NADPH-d) histochemistry was used.
- The study examined the digestive tract, gallbladder, pancreas, and sphincter of Oddi in monkeys and humans.
- Double-labeling experiments were performed on pancreatic tissue.
Main Results:
- NADPH-d activity, indicating NOS presence, was abundant in myenteric and submucous plexuses of the gastrointestinal tract.
- Stained nerve fibers were observed in the muscular layers, mucosa, and vasculature.
- NO-producing neurons were identified in the gallbladder, sphincter of Oddi, and pancreas, with most pancreatic NO neurons co-expressing vasoactive intestinal peptide.
Conclusions:
- NO-producing neurons are widely distributed throughout the digestive system, gallbladder, and pancreas.
- The findings support NO's role as a key neurotransmitter in regulating smooth muscle and vascular function in these organs.
- The study highlights the utility of NADPH-d histochemistry for mapping NO pathways in the gastrointestinal system.