Messenger Plasticity in Primary Sensory Neurons Following Axotomy and Its Functional Implications

Following peripheral axotomy, long-lasting changes in the expression of neuropeptides and their receptors in primary sensory neurons are observed. These changes involve the downregulation of the excitatory peptides substance P and calcitonin gene-related peptide and the upregulation of the inhibitory peptides neuropeptide tyrosine and galanin, resulting in a reduction of transmission in the dorsal horn. The changes observed are thought to represent adaptive responses to limit the consequences of peripheral nerve damage to the organism as a whole and to promote survival and recovery of the individual neuron.