Compensatory dendritic growth of CA1 pyramidal cells following growth impairment in the neonatal period


  • Present address: Laboratory de Physiologie cellulaire de la synapse, CNRS-UMR 5091, Institut François Magendie, 1 rue Camille Saint-Saëns, 33077 Bordeaux, France.

: Dr Laurent Groc, †at present address below.


In the neonatal rat, inhibition of hippocampal neural activity in vivo by tetanus toxin results in a severe growth impairment of the basal dendrites of CA1 pyramidal cells. Here we tested whether this early growth impairment results in a permanent reduction of the basal dendritic tree or whether recovery processes are recruited later in development when synaptic activity has fully recovered. Quantitative analysis of dendritic parameters and spine density from reconstructed CA1 pyramidal cells showed that young adult CA1 pyramidal (postnatal day 31–34) cells that were exposed to activity deprivation in the neonatal period were almost indistinguishable from control cells of the same age. These results suggest that the early hippocampal activity controls the growth rate but is not necessary for the generation of an adult normal basal dendritic tree.