Sensory receptors in the equine foot.

The research found two types of sensory receptors in a horse’s foot, one that possibly responds to pressure and vibrations, and another that may be sensitive to pain.

Identification of Sensory Receptors

• The researchers used anatomical techniques to locate two distinct types of sensory receptors in the equine foot.
• Using histological examination of stained hoof sections, they found lamellated corpuscles in the hoof dermis, resembling Pacinian corpuscles and primarily existing in the solar dermis of the horse’s heel.

Second Type of Receptor

• A different type of receptor was discovered using immunocytochemistry, highlighting unshielded nerve endings containing a certain neuropeptide – calcitonin gene-related peptide-like immunoreactivity.
• The findings indicated that this receptor was found in skin, solar dermal tubules, and the digital cushion.

Neurotransmitter Characteristics

• The researchers highlight the peptide as an example of a sensory neurotransmitter existing in dorsal root ganglion cells. This type of neurotransmitter is believed to be present only in sensory nerve fibres without a myelin sheath.

Potential Role of Sensory Receptors

• The researchers hypothesized that the two distinct receptor types play different roles in horses’ perception of their surroundings.
• The study suggests that the lamellated (or Pacinian-like) corpuscles might be used to detect sensory stimuli such as pressure or vibrations.
• The receptors containing the calcitonin gene-related peptide-like immunoreactivity, on the other hand, may be responsible for detecting pain stimuli.
• The findings relate to horses’ locomotory gaits and could provide vital insights into how changes in sensory perception can affect their mobility.