Kindling is associated with the formation of novel mossy fibre synapses in the CA3 region.

A Golgi and electron microscopy study of the hippocampal CA3 region was performed on control and kindled Wistar rats. The observations provide evidence that, in epileptic rats, mossy fibres sprout and establish novel synapses with the basilar dendrites of CA3 pyramidal neurons. These newly-developed synapses showed the typical features of mossy synapses observed in the stratum lucidum, including the appearance of complex giant spines. The morphological changes reported here may represent a histopathological substrate for the epilepsy in the absence of overt signs of a hippocampal lesion.