Renshaw cells are inhibitory interneurons found in the gray matter of the spinal cord, and are associated in two ways with an alpha motor neuron.
Renshaw cells thus act as "limiters," or "governors," on the alpha motor neuron system, thus helping to prevent muscular damage from tetanus.
Renshaw cells are also the target of the toxin of Clostridium tetani, a Gram positive, spore-forming anaerobic bacterium that lives in the soil, and causes tetanus.
When wounds are contaminated with C. tetani, the toxin travels to the spinal cord where it inhibits the release of glycine, an inhibitory neurotransmitter, from Renshaw cells.
Later work by Eccles et al.,[14] provided evidence that these interneurons, which they called “Renshaw Cells,” are stimulated by acetylcholine from motor neurons (nicotinic receptor).
In the event where the initial stimulation of the motor neuron originated in a spinal tract the Renshaw cell spike occurred during the declining phase of the initial motor neuron soma spike giving an indication of the source and sequence of stimulation of the Renshaw cell.