Chapter 2 Fetal cortical cell suspension grafts to the excitotoxically lesioned neocortex: anatomical and neurochemical studies of trophic interactions

Abstract

Publisher Summary Neural grafting has emerged as an interesting tool for the study of trophic neuron-target interactions in the central nervous system. This chapter describes a model for the study of trophic interactions in the adult neocortex based on extensive kainic acid (KA) -induced or Nmethyl-D-aspartate (NMDA) -induced cortical damage and subsequent intracortical suspension grafts of foetal cortical tissue. The chapter also presents neurochemical and basic morphological features of the KA lesion and the cortical suspension grafts. The fetal neocortical tissue, implanted in the form of multiple deposits of a dissociated cell suspension, can survive and differentiate in the depth of the KA- or NMDA-lesioned cortex of adult recipient rats. In adult rats, the neuron-depleted excitotoxically lesioned cortex provides a better growth environment for the fetal tissue than the non-lesioned one. Various observations indicate that the excitotoxic lesion may favor graft growth by the provision of both growth space and opportunities for trophic or connectivity interactions with the host brain. The anatomical studies of the lesioned neocortex with intracortical cell suspension grafts also indicate that several of the normal cortical inputs have the capacity to grow into the grafts. The chapter concludes that the excitotoxic cortical lesion and graft model offers several interesting observations regarding the general consequences of neocortical degeneration and the neocortical cellular and neurochemical interactions of a neurotrophic nature; however, studies that are more detailed are needed.