Identifying spinal afferent (sensory) nerve endings that innervate the marrow cavity and periosteum using anterograde tracing

Abstract

While sensory and sympathetic neurons are known to innervate bone, previous studies have found it difficult to unequivocally identify and characterize only those that are of sensory origin. In this study, we have utilized an in vivo anterograde tracing technique to selectively label spinal afferent (sensory) nerve endings that innervate the periosteum and marrow cavity of murine long bones. Unilateral injections of dextran–biotin (anterograde tracer; 20% in saline, 50–100 nl) were made into L3–L5 dorsal root ganglia. After a 10-day recovery period to allow sufficient time for selective anterograde transport of the tracer to nerve terminal endings in bone, the periosteum (whole-mount) and und..