Perineural microtubule inhibitors induce degenerative atrophy of central nociceptive terminals in the Rolando substance.

Short-term perineural application of a microtubule inhibitor around a peripheral nerve induces degenerative atrophy of primary central nociceptive terminals in the Rolando substance. Consequences of the local microtubule inhibitor treatment are identical, both at light- and electron microscopic levels, with those that follow transection of a peripheral nerve. Degenerative atrophy in the Rolando substance is due to arrested axoplasmic transport in, and not to Wallerian degeneration of, the peripheral axons since (1) locally applied vinblastine and vincristone do not induce peripheral degeneration at all and (2) even though local colchicine treatment may cause Wallerian degeneration of thick myelinated axons, thin Adelta and C fibers do not undergo degeneration after colchicine treatment. The intriguing possibility to use this approach in the treatment of intractable pain is discussed.