Stress-induced activation of the immediate early gene Arc (activity-regulated cytoskeleton-associated protein) is restricted to telencephalic areas in the rat brain: relationship to c-fos mRNA

ONS SHEILA; MARTÍ OCTAVI; ARMARIO ANTONIO

JOURNAL OF NEUROCHEMISTRY

Año: 2004 vol. 89 p. 1111 - 1118

0022-3042

Arc is an effector immediate early gene whose expression isinduced in situations of increased neuronal activity. However,there is no report on the influence of stress on Arc expression.Here, we compared the induction of both c-fos and ArcmRNAs in the brain of rats exposed to one of three differentstressful situations: novel environment, forced swimming andimmobilization. An absent or weak c-fos mRNA signal wasobserved in control rats, whereas those exposed to one ofthree stressors showed enhanced c-fos expression in a widerange of brain areas. Constitutive Arc expression wasobserved in some areas such as cortex, striatum, hippocampus,reticular thalamic nucleus and cerebellar cortex. Inresponse to stressors, a strong induction of Arc was observed,but the pattern was different from that of c-fos. For instance,activation of Arc but not c-fos was observed in the nucleusaccumbens after immobilization and in the hippocampus afternovel environment. No Arc induction was observed in diencephalicand brainstem areas. The present data show that Archas a neuroanatomically restricted pattern of induction in thebrain after emotional stress. Telencephalic activation suggeststhat a more intense induction of synaptic plasticity isoccurring in this area after exposure to emotional stressors.