Tyrosinated alpha-tubulin changes following epileptogenic and non-epileptogenic lesions in rat brain cortex

The expression of the tyrosinated isoform of alpha-tubulin was monitored in rat frontal cortex, in order to investigate the neuronal plasticity changes occurring either in a mirror focus or in a deafferented area. A mirror focus was triggered by epidural implantation of a cobalt gelatin disk in the contralateral left somatosensory area (group one). A deafferented area was obtained by surgical removal of the left frontal cortex (group two). All animals including controls underwent EcoG recordings immediately before killing (45, 60, 90 days post surgery). The right frontal cortex was removed from all the animals and processed with Western blot method. EcoG recordings revealed a paroxysmal activity in epileptic rats, whereas in rats with frontal deafferentation and controls, EcoG activity was normal. A significant increase in tyrosinated alpha-tubulin expression was detected both in the mirror focus (group one) and the "non-epileptic" deafferented frontal cortex (group two) in comparison with controls (group three). The transcallosal deafferentation, which is involved in both epileptogenic and non-epileptogenic lesions, is supposed to play a role in the mechanism responsible for the plasticity responses recorded in the cortical areas studied.