ORGANOPHOSPHOROUS NEUROPATHY .1. TEASED-FIBER STUDY OF THE SPATIO-TEMPORAL SPREAD OF AXONAL DEGENERATION

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  • 1 January 1979
    • journal article
    • research article
    • Vol. 94  (2) , 241-251
Abstract
The spatio-temporal spread of axonal degeneration in organophosphorous neuropathy was studied by the teased-fiber technique. Young adult cats were given a single i.p. injection of DFP and were killed 14, 18, 20, 21 and 28 days later by intracardiac perfusion with aldehydes. The cats developed clinical signs of delayed neurotoxicity 16-18 days after DFP injection. A histologic survey of the central and peripheral nervous systems revealed that the topographic distribution of axonal degeneration was characteristic of a dying-back neuropathy. In teased-fiber preparations from the left recurrent laryngeal nerve, the axonal degeneration was initially focal and nonterminal but that the axonal degeneration subsequently spread in a stomatofugal direction to involve the entire distal axon. Nerve fiber varicosities and paranodal demyelination preceded the axonal degeneration. Neurotoxic organophosphates induce a focal, distal but not terminal, axonal degeneration. This chemical transection of the axon then precipitates Wallerian degeneration of the more distal axon. The traditional hypothesis that dying-back neuropathies evolve from a retrograde axonal degeneration is not valid for organophosphorous neuropathy.