The role of nitric oxide in the neuroprotection of limb ischemic preconditioning in rats.
Brief limb ischemia was reported to protect neurons against injury induced by subsequent cerebral ischemia-reperfusion, and this phenomenon is known as limb ischemic preconditioning (LIP). To explore the role of nitric oxide (NO) in neuroprotection of LIP in rats, we observed changes in the content of nitric oxide (NO) and activity of NO synthase (NOS) in the serum and CA1 hippocampus of rats after transient limb ischemic preconditioning (LIP), and the influence of N(G)-nitro-L-arginine methylester (L-NAME), a NOS inhibitor, on the neuroprotection of LIP against cerebral ischemia-reperfusion injury. Results showed that NO content and NOS activity in serum increased significantly after LIP compared with the sham group. The increase showed a double peak pattern, in which the first one appeared at time 0 (immediate time point) and the second one appeared at 48 h after the LIP (P < 0.01). The NO content and NOS activity in the CA1 hippocampus in LIP group showed similar change pattern with the changes in the serum, except for the first peak of up-regulation of NO content and NOS activity appeared at 6 h after LIP. Pretreatment with L-NAME before LIP blocked the neuroprotection of LIP against subsequent cerebral ischemic insult. The blocking effect of L-NAME was abolished with pretreatment of L-Arg. These findings indicated that NO may be associated with the tolerance of pyramidal cells in the CA1 hippocampus to ischemia induced by LIP in rats.
Zhao
Hong-Gang
HG
Department of Pathophysiology, Institute of Basic Medicine, Hebei Medical University, 361 Zhongshan East Road, 050017 Shijiazhuang, P R China.
Sun
Xiao-Cai
XC
Xian
Xiao-Hui
XH
Li
Wen-Bin
WB
Zhang
Min
M
Li
Qing-Jun
QJ
D000818:Animals; D002545:Brain Ischemia / Q000503:physiopathology*; D006614:Hindlimb / Q000098:blood supply*; D006624:Hippocampus / Q000378:metabolism; D019194:Ischemic Preconditioning; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood / Q000502:physiology*; D051381:Rats
D018696:Neuroprotective Agents; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester