Are nociceptin(1‐13)NH 2 and its structural analogue [ORN 9 ]nociceptin(1‐13)NH 2 able to affect brain antioxidant status in control and kainic acid‐treated rats?

In‐vivo effects of nociceptin (N/OFQ(1‐13)NH 2 ) on the levels of lipid peroxidation and cell enzyme (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non‐enzyme (glutathione) antioxidants in brain of control and kainic acid‐treated rats were studied. N/OFQ(1‐13)NH 2 effects were compared with those of its structural analogue [Orn 9 ]N/OFQ(1‐13)NH 2 . Kainic acid (25 µg, i.c.v) increased the lipid peroxidation (4 and 24 h after kainic acid treatment) and decreased the glutathione level (1 h after kainic acid injection). We failed to find, any changes in antioxidant enzyme activities, independently of the time of kainic acid treatment. At the background of kainic acid‐effects, N/OFQ(1‐13)NH 2 and [Orn 9 ] N/OFQ(1‐13)NH 2 , injected 30 min before kainic acid, had no effects on all parameters, tested in brain. In addition, the neuropeptides did not change the antioxidant status in brain of control animals. It might be concluded that N/OFQ(1‐13)NH 2 and [Orn 9 ]N/OFQ(1‐13)NH 2 have neither pro‐ nor anti‐oxidant activity. Copyright © 2009 John Wiley & Sons, Ltd.