Comparison Between the Early Changes in Isoniazid Intoxication and the Chromatolytic Response to Nerve Ligation in Spinal Ganglion Cells of the Rat

Abstract

The early effects of acute isoniazid intoxication and the early responses of the neuron to axotomy have been compared in lumbar spinal ganglion cells in the rat. The cells were studied by light and electron microscopy during the 4 days after a single oral dose (2g/kg) of isoniazid and for four days after application of a tight ligature to the sciatic nerve at the level of the sciatic notch. After axotomy a greater proportion of cells showed changes visible by light and electron microscopy than after INH. Small dark neurons were affected more rapidly and more severely by both insults than the large light cells as evidenced principally by changes in their ribosomal organization. Large light cells showed little response to INH. The first response to axotomy was visible about 12 h after injury. The response to INH began 24 h after the single oral dose. The early cell responses to INH therefore apparently precede axon degeneration which is first seen 72 h later and are thus probably a direct toxic effect.

Target-dependence of sensory neurons: An ultrastructural comparison of axotomised dorsal root ganglion neurons with allowed or denied reinnervation of peripheral targets

“…Retrogradely labelled cell bodies had a wide range of diameters (20-80 µm) with a mean of 40µm (see also Larnicol et al, 1988). The light and electron microscopic features were similar to those described previously (Lieberman, 1976, Jones andCavanagh, 1981), although the light microscopic distinction between large light and small dark DRG neurones was not clear cut (FIG 4). In all neurones, nuclei were circular and centrally-placed within the cell body; nucleoli were compact and prominent; Nissl substance was mostly evenly distributed throughout the cell body.…”

Electron microscopy

“…The lesions seen by us in the coeliacomesenteric ganglion are similar to those described by Gilmour (1975) in the stellate ganglion and would seem to be similar in many ways to retrograde lesions following chemical intoxication, axotomy and ligature of axons of peripheral nerves. All of these retrograde changes as stated by Jones and Cavanagh (1981) are similar, although differing slightly in detail.…”

Immunocytochemical and lectin histochemical study of neuronal lesions in autonomic ganglia of horses with grass sickness

“…The axonal reaction, after axotomy, is often accompanied by a chromatolytic appearance of neuronal perikarya. The Golgi network is always recognisable in motor, sensory and autonomic neurons after experimental axotomy although alterations in size and intracytoplasmic distribution of the complexes may occur (Matthews and Raisman 1972;Jones and Cavanagh 1981;Croul et al 1988). Based on this evidence we suggest that the 'chromatolytic' changes in EGS do not represent an axonal reaction to primary lesions more distally in the axon although it is possible that the axonal reaction in horses differs from that in other species.…”