Neurons expressing NADPH-diaphorase in the developing human spinal cord

Area of Science:

• Neuroscience
• Developmental Biology
• Histochemistry

Background:

• Nitric oxide (NO) is a signaling molecule implicated in various physiological processes.
• Understanding the role of NO in neuronal development is crucial for comprehending spinal cord formation.
• Previous studies in rodents identified specific neuronal migration patterns involving NO.

Purpose of the Study:

• To identify neurons expressing nitric oxide synthase (NOS) in the developing human spinal cord using NADPH-diaphorase histochemistry.
• To describe the migratory pathways of these NOS-expressing neurons during human spinal cord development.
• To investigate the potential role of NO in neuronal migration and differentiation.

Main Methods:

• Nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase histochemistry was employed.
• Human spinal cord tissue from gestational weeks 6 to 14 was analyzed.
• Cellular localization and migratory patterns of diaphorase-positive neurons were documented.

Main Results:

• Diaphorase expression was detected as early as gestational week 6 in sympathetic preganglionic neurons (SPNs) and ventral horn interneurons.
• SPNs exhibited dorsal translocation to form the intermediolateral nucleus, with a distinct dorsomedial migratory pathway observed.
• Two 'U-shaped' cell populations were identified at week 7, migrating dorsally to form deep dorsal horn and central canal interneurons.

Conclusions:

• Nitric oxide is present very early in human spinal cord development.
• Two unique neuronal migration patterns, previously identified in rodents, are confirmed in humans.
• NO expression during migration suggests a potential role in guiding neuronal positioning and development.