• Journal of Korean Orthopaedic Sports Medicine
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• v.4 no.1
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• pp.29-35
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• 2005

Purpose: The anterior cruciate ligament(ACL) has a neuromuscular control function as evidenced by the presence within it of mechanoreceptor. Although these mechanoreceptors have been identified, the afferent somatosensory pathways from ACL to the cerebrum have yet to be demonstrated in their entirety. In order to trace these afferent pathway, we conducted a viral trans-synaptic tracing experiment using the neurotropic pseudorabies virus(PRV). Material and Methods: The PRV was injected into the ACL of rats and allowed to replicate and spread trans-synaptically for 6 to 7 days. The brain and spinal cord of each sacrificed rat was then removed and processed immunohistochemically to detect the presence of PRV. Results: PRV-immunoreactive neurons were found to be localized in several different regions from the spinal cord to the cerebrum. Four nuclei in the reticular formation of the brain stem demonstrated strong positive labeling: the mesencephalic reticular nucleus, magnocelluar reticular nucleus, paragigantocellular reticular nucleus, and gigantocellular reticular nucleus. Conclusions: This findings suggests that the nerve endings of the rat ACL project into the cerebrum and that the reticular formation may play an important role in the afferent pathway of those nerve endings.