MODIFICATION OF ACTIN IN PERITONEAL-MACROPHAGES AFTER DIAZEPAM TREATMENT

We have investigated the effect of therapeutic doses of diazepam (7 mu g/mouse) on the association of actin with the macrophage cytoskeleton using cytochemical and morphological methods. Results obtained indica ted that diazepam was able to modulate the content of actin in macroph ages; such an effect proved to be time-dependent. After fixation and s taining for indirect immunofluorescence with actin antibody, peritonea l macrophages from mice treated for short time with diazepam, showed a fluorescent intensity increase compared to control mice. The fluoresc ent intensity augmented reaching peak value within 14 days of treatmen t. Afterwards, this value dropped below control value for mice that un derwent longer treatments. In the in vitro experiments concentrations of 10(-5) M, diazepam inhibited a well cell spread and a lower amount of actin after 15 min of incubation was also revealed. These results s uggest that administration of diazepam in vivo plays a role in both th e nonspecific and specific immune response, producing in the macrophag es a reorganization process of microfilaments.