14] - Retrograde Axoplasmic Transport of Neurotoxins

Abstract

This chapter focuses on the retrograde axoplasmic transport of neurotoxins. Neurons have both anterograde and retrograde axoplasmic transport systems. Anterograde flow carries such subcellular organelles as neurotubules, neurofilaments, and mitochondria and soluble molecules necessary for neuronal functions and maintenance. Some soluble molecules include neurotransmitters and their precursors, which synthesize and degrade enzymes. Retrograde axoplasmic transport conveys peripheral information from nerve terminals to their soma and is involved in recycling of the anterograde transported materials. Alteration of axoplasmic transport may profoundly influence neuronal functions and, conversely, the malfunctioning neuronal machinery may give rise to the perturbation of the axoplasmic flow. A simple axotomy with resultant interruption of bidirectional flow causes degeneration of the distal axons and central chromatolysis. If one is able to manipulate neurons to degenerate or to die by means of retrograde axoplasmic transport, it would be important to understand the cellular events occurring in relation to retrograde axoplasmic flow. The chapter further reviews some concepts, such as retrograde suicide agents, suicide transport as a neuroanatomical method, experimental form and theories of motor neuron diseases, pain control by retrograde sensory ganglionectomy, eradication of herpesvirus persistence in sensory ganglia, and perspectives of suicide transport as a research method.