Perforant path lesion induces up-regulation of stathmin messenger RNA, butnot SCG10 messenger RNA, in the adult rat hippocampus

In this study, we performed in situ hybridization analysis of the expressio n pattern of two growth-associated proteins, stathmin and SCG10, in the hip pocampus after unilateral lesion of the perforant pathway, the main excitat ory input from the entorhinal cortex to the hippocampus. Stathmin is one of the major neural-enriched cytosolic phosphoproteins and a potential target of cyclic-AMP-dependent kinases [Jin L. W. et al. (1996) Neurobiol. Aging 17, 331-341; Leighton I. A. et al. (1993) Molec. Cell Biochem. 127/128, 151 -156]. Three days after the lesion, stathmin messenger RNA was up-regulated ipsilaterally in the hilus, in the granule cell layer of the dentate gyrus and in the pyramidal cell layer of the CA1 region. Simultaneously, the hil ar region of the contralateral dentate gyrus showed an increased stathmin m essenger RNA expression. This altered expression pattern was observed until 15 days after lesion. Stathmin messenger RNA expression returned to a norm al level until 21 days after lesion in all regions analysed. SCG10, a membr ane-bound neuronal growth-associated protein belonging to the SCG10/stathmi n gene family, did not show any alteration of messenger RNA expression afte r perforant path lesion. The temporal changes of stathmin messenger RNA expression in the ipsilatera l hippocampus correspond well to the process of reactive synaptogenesis. Th e enhanced messenger RNA expression in the hilar region of the contralatera l dentate gyrus might suggest a role in neurite elongation, since this regi on is the origin of commissural fibres involved in the sprouting response i n the deafferented hippocampus. The present study provides evidence that th e induction of specific growth-associated proteins is differentially regula ted in the hippocampus. (C) 2001 IBRO. Published by Elsevier Science Ltd. A ll rights reserved.