Stress differentially regulates synaptophysin and synaptotagmin expressionin hippocampus

Background: In view of the effects of stress on synaptic plasticity,, the r egulation of synaptophysin and synaptotagmin expression by immobilization w as analyzed by in situ hybridization. Methods: Rats were exposed to immobilization stress, which induced typical behavioral alterations, such as reduced locomotor activity after stress exp osure. Determination of mRNA levels of the integral synaptic vesicle protei ns was performed immediately after acute or chronic immobilization. Results: The results demonstrate that stress exposure leads to reduced expr ession of synaptophysin but increased expression of synaptotagmin in the hi ppocampus. Conclusions: This rapid and differential regulation of synaptic vesicle pro teins could be responsible for some of the morphological, biochemical, and behavioral changes observed after stress exposure. These changes may be rel evant to such clinical disorders as psychoses, depression, and posttraumati c stress disorder that are sensitive to stress and involve changes in neutr al and synaptic plasticity. (C) 2001 Society, of Biological Psychiatry.