Calbindin-D28K (CaBP28k)-like Immunoreactivity in Ascending Projections

Area of Science:

• Neuroscience
• Spinal Cord Research
• Pain Perception

Background:

• Ascending spinal pathways transmit sensory information, including pain and visceral signals, to the brain.
• Calbindin-D28K (CaBP28k) is a calcium-binding protein known to regulate neuronal excitability.
• Understanding the role of specific neuronal populations in sensory processing is crucial for pain and visceral disorder research.

Purpose of the Study:

• To investigate the presence and distribution of calbindin-D28K (CaBP28k)-containing neurons in spinal ascending projections.
• To determine the role of CaBP28k in neurons involved in processing visceroception and visceronociception.
• To compare the prevalence of CaBP28k-expressing neurons in ascending pathways with other known neuronal markers.

Main Methods:

• Utilized a double labeling technique combining retrograde transport of a protein-gold complex with immunohistochemistry.
• Identified projection neurons by their retrograde transport of the tracer.
• Identified CaBP28k-positive cells using immunohistochemistry, and colocalization indicated CaBP28k-containing projection neurons.

Main Results:

• CaBP28k-containing neurons are numerous in caudal spinal cord areas involved in visceroception.
• High concentrations of CaBP28k-positive projection neurons were found in superficial dorsal horn (laminae I, outer II) and lateral spinal nucleus.
• Other significant locations included the dorsal horn neck, laminae VII, VIII, X, and the sacral parasympathetic nucleus.

Conclusions:

• CaBP28k is highly prevalent in spinal ascending pathways involved in processing visceral and pain information.
• These findings suggest a significant role for CaBP28k in modulating spinal neuronal excitability for supraspinal sensory transmission.
• The abundance of CaBP28k-immunoreactive cells in these pathways exceeds that of previously studied neuropeptides.