Neurocalcin-immunoreactive neurons in the mammalian dorsal root ganglia, including humans.

The research article investigates the occurrence of Neurocalcin, a calcium-binding protein, in the dorsal root ganglia (comprised of sensory neurons) of several mammalian species, including humans. They found that different species, neuron sizes, and peripheral nervous system neurons display varied levels of Neurocalcin immunoreactivity.

Objective and Methodology

• The purpose of the study was to examine the occurrence of Neurocalcin (NC) – a EF-hand calcium-binding protein that was recently characterized – in the dorsal root ganglia (DRG) of a wide range of mammalian species, including horses, buffalos, cows, sheep, pigs, dogs, rats, and humans.
• In order to achieve this, researchers fixed dorsal root ganglia, embedded them in paraffin, and processed them for immunohistochemistry using a polyclonal antibody against NC.
• The size of the immunoreactive neurons was measured as part of the experiment.

Observations and Findings

• The study found that all species examined display NC immunoreactivity (IR) in neurons. However, the percentage and size of the immunoreactive neurons varied amongst the different species.
• Generally, smaller neurons (those with a diameter of less than 20 micrometers) did not display NC IR.
• In some species, such as pigs, dogs, buffalos, and cows, only the largest neurons demonstrated IR. But in others, such as sheep, horses, rats, and humans, a full range of neuron sizes showed this quality.
• The pattern of immunostaining was cytoplasmic, although for some species, such as cows and buffalo, it formed a peripheral “ring.”

Conclusions and Implications

• The present study demonstrated that the DRG in mammals contain a subpopulation of neurons that are positive for NC, the prevalence of which varies between species.
• Though not explicitly stated, these findings imply that the function of NC-containing neurons may differ depending on neuron size and the specific mammalian species being considered, which would warrant additional research for a more detailed understanding.