Odor regulates the expression of mitogen-activated protein kinase phosphatase gene hVH-5 in bilateral entorhinal cortex-lesioned rats.

BERNABEU, R ; DI SCALA, G.; ZWILLER J

MOLECULAR BRAIN RESEARCH

ELSEVIER

Lugar: Amsterdam; Año: 2000 vol. 75 p. 113 - 120

0169-328X

Since it is known that several immediate early genes are induced by olfactory stimuli, we determined whether an olfactory stimulusalso induces the expression of the mitogen-activated protein kinase MAPK. phosphatase gene hVH-5 homologue of vaccinia virus H1phosphatase gene, clone 5., a member of a novel class of immediate early genes encoding dual-specificity protein phosphatases. Theexpression was studied by in situ hybridization in different brain structures involved in odor processing, in control and bilateral entorhinalcortex EC. lesioned rats. EC-lesion did not significantly affect hVH-5 gene expression in the glomerular cell layer of the olfactory bulbOB., while odor stimulation induced it in both control and EC-lesioned groups. In contrast, odor-induced expression of hVH-5 gene inmitralrgranular cell layers was only evident after lesion of the EC. Similar results were obtained in the piriform cortex PCx., a structureintimately connected to the mitral cell layer. In the CA1 hippocampal subfield, odor stimulation induced hVH-5 gene expression in bothcontrol and EC-lesioned animals, the increase being potentiated in lesioned rats. CA3 and dentate gyrus exhibited a similar pattern ofgene expression, the odor stimulating gene expression in both control and lesioned groups. The amygdala Am. displayed no significantchange. It appears that through the induction of a MAPK phosphatase, the EC controls MAPK activities differently after odor stimulationin OB, PCx and hippocampus Hip.. The results illustrate the notion that odor representation in the brain requires plastic modifications atboth anatomical and functional levels.