Down Regulation of C-Fos and C-Jun Expressions in Chronic Meperidine-Treated Patients

Objectives. Meperidine is one of the most widely used analgesics in clinical practice. Previous data suggested that chronic administration of opioids might lead to long-lasting adaptations on neuronal circuits in the brain. c-fos and c-jun are induced rapidly but transiently in certain brain regions by acute administration of opiates. Chronic exposure may desensitize the ability of the seproteins to be induced. The purpose of this study was to investigate c-fos and c-jun expressions in peripheral blood lymphocytes in patients with chronic exposure to meperidine. Methods. The exposure group comprised 5 patients who received meperidine for at least 6 months. We selected 12 healthy adult volunteers with no medical history of opiate administration as the control group. Peripheral blood was drawn by venipuncture. Total RNA was isolated and reverse transcription was performed. Quantitative competitive PCR was performed to quantify the human c-fos and c-jun. All statistical data were expressed as mean SEM. Results. The c-fos level in the peripheral blood of the patients who underwent prolonged meperidine treatment was much lower than that of healthy individuals who had not been exposed to meperidine. While the c-fos level of healthy individuals decreased with time after phytoagglutinin (PHA) treatment, it did not change in those chronically exposed to meperidine. Conclusions. Chronic exposure to meperidine desensitized c-fos and c-jun expression in the peripheral blood lymphocytes of patients with chronic exposure to meperidine.