[ neuroprotective effect of cannabinoid receptor agonist [WIN55,212-2] in paraoxon induced neurotoxicity in PC12 cells and N-methyl-D-aspartate receptor interaction]

Considering that cannabinoids protect neurons against neurodegeneration, in this study, the neuroprotective effect of WIN55,212-2 in paraoxon induced neurotoxicity in PC12 cells and the role of the N-methyl-D-aspartate [NMDA] receptor were evaluated. In this study PC12 cells were maintained in Dulbecco's modified eagle's medium [DMEM+F12] culture medium supplemented with 10% fetal bovine serum. The cells were treated with paraoxon [200 micro M] in the presence or absence of WIN55,212-2 [0.1 micro M], NMDA receptor agonist NMDA [100 micro M], cannabinoid receptor antagonist AM251 and NMDA receptor antagonist MK801 [1 micro M] at 15 minutes intervals. After 48 hours of exposure, cellular viability and protein expression of the CB1 receptor were evaluated in PC12 cells. Following the exposure of PC12 cells to paraoxon [200 micro M], a reduction in cell survival and protein level of the CB1 receptor was observed [p<0.01]. Treatment of the cells with WIN55,212-2 [0.1 micro M] and NMDA [100 micro M] prior to paraoxon exposure significantly elevated cell survival and protein level of the CB1 receptor [p<0.01]. Also, AM251 [1 micro M] did not inhibit the cell survival and protein level of the CB1 receptor increase induced by WIN55,212-2 [p<0.001]. However, MK801 [1 micro M] did inhibit cell survival and protein expression of the CB1 receptor increase induced by NMDA [p<0.001]. The results indicate that WIN55,212-2 and NMDA protect PC12 cells against paraoxon induced toxicity. In addition, the neuroprotective effect of WIN55,212-2 and NMDA was cannabinoid receptor-independent and NMDA receptor dependent, respectively

Diclofenac inhibits proliferation but not NGF-induced differentiation of PC 12 cells

Diclofenac is a non-steroidal anti-inflammatory drug that is prescribed for treatment of rheumatic diseases and as an analgesic. Although the information about these side effects has been widely reported, little is know about the effect of diclofenac on the neural cells. In this study, we investigated the effects of diclofenac on the proliferation and differentiation of PC12 cells. The cell proliferation was evaluated by using XTT assay in the both free-serum neurobasal medium supplemented with B27 supplement and DMEM/F12 medium containing 10% FBS. The nerve growth factor [NGF]-induced differentiation was assessed by measuring the neurite length. The drug toxicity was exhibited at the concentrations more than 310 microM in the supplemented neurobasal medium. The treatment of cells in the DMEM/F12 medium increased their sensitivity to diclofenac, with 40% and 75% growth inhibition at the 155 and 310 microM concentrations, respectively. The NGF-induced differentiation was not reduced by toxic and subtoxic concentrations of diclofenac. The results of this study indicated that diclofenac may be able to exhibit its neurotoxic effects through growth inhibition, but not differentiation inhibition. Supplement of B27 has several antioxidant compounds. Therefore, the difference of diclofenac cytotoxic effects in two culture media suggest that drug cytotoxicity may be related to the oxidative stress