Cortical layer III pyramidal dendritic morphology normalizes within 3 weeks after kindling and is dissociated from kindling-induced potentiation

This experiment examined the effect of a 3-week rest after electrical kindling on kindling-induced potentiation and the morphology of frontal (Fr1) neocortical layer III pyramidal cell dendrites in both male and female rats, Repeated elicitation of afterdischarge resulted in an increase in the severity of the behavioural seizures and afterdischarge duration. The late component of the transcallosal evoked responses was significantly larger 1 and 21 days following the last kindling session in both male and female rats. Analysis of the Golgi-Cox impregnated pyramidal cell dendrites indicated no significant difference in the amount of apical and basilar dendritic, branching, length, and spine density in both male and female rats, relative to their respective control groups, 21 days following the last kindling session. There was, however, one exception, the male group showed a significant increase in apical spine density. The persistent expression of kindling-induced potentiation appears to be dissociated from the renormalized pyramidal cell dendritic morphology. (C) 2001 Elsevier Science B.V. All rights reserved.