Related Experiment Video
Updated: Aug 7, 2026
Bilateral Common Carotid Artery Occlusion as an Adequate Preconditioning Stimulus to Induce Early Ischemic Tolerance to Focal Cerebral Ischemia
Published on: May 9, 2013
Nitric oxide participates in the induction of brain ischemic tolerance via activating ERK1/2 signaling pathways
Hui-Qing Liu1, Wen-Bin Li, Qing-Jun Li
1Department of Neurology, Ren Min Hospital of Hebei province, Shijiazhuang 050000, PR China.
Abstract:
The present study was undertaken to observe in vivo changes of expression and phosphorylation of ERK1/2 proteins during brain ischemic preconditioning and effects of inhibiting generation of nitric oxide (NO) on the changes to determine the role of ERKs in the involvement of NO participating in the acquired tolerance. Fifty-five Wistar rats were used. Brain ischemic preconditioning was performed with four-vessel occlusion for 3 min. Total ERK1/2 proteins and phospho-ERK1/2 in the CA1 hippocampus were assayed with Western immunoblot. Total ERK1/2 proteins did not change in period from 5 min to 5 days of reperfusion after preconditioning stimulus. While the level of phospho-ERK1/2 increased obviously to 223, 237, 300, 385 and 254% of sham level at times of 5 min, 2 h, 1, 3 and 5 days after preconditioning stimulus, respectively (P < 0.01). Administration of L-NAME, an inhibitor of NO synthase, 30 min prior to preconditioning stimulus failed to induce change in total ERK1/2 proteins (P > 0.05). However, phospho-ERK1/2 increased only to 138 and 176% of sham level at 2 h and 3 days after preconditioning stimulus, respectively, when animals were pretreated with L-NAME. The magnitudes of the increase were obviously low compared with those (237 and 385%) in animals untreated with L-NAME at corresponding time points (P < 0.01), which indicated that phosphorylation of ERK1/2 normally induced by preconditioning stimulus was blocked apparently by administration of L-NAME. The results suggested that phosphorylation of ERK1/2, rather than synthesis of ERK1/2 proteins, was promoted in brain ischemic preconditioning, and that the promotion was partly mediated by NO signal pathway.
Insights
Brain ischemic preconditioning enhances ERK1/2 phosphorylation, a process partly mediated by nitric oxide (NO) signaling. This study investigated ERK1/2 changes and NO
Area of Science:
- Neuroscience
- Cellular Biology
- Biochemistry
Background:
- Brain ischemic preconditioning confers neuroprotection against subsequent ischemic insults.
- Extracellular signal-regulated kinases (ERK1/2) are implicated in cellular signaling pathways involved in neuroprotection.
- Nitric oxide (NO) is a signaling molecule with a known role in regulating vascular and neuronal functions during ischemia.
Purpose of the Study:
- To investigate in vivo changes in ERK1/2 protein expression and phosphorylation following brain ischemic preconditioning.
- To determine the effect of inhibiting nitric oxide (NO) synthase on ERK1/2 phosphorylation during ischemic preconditioning.
- To elucidate the role of NO in the ERK1/2 signaling pathway during acquired tolerance to brain ischemia.
Main Methods:
- Wistar rats underwent a 3-minute four-vessel occlusion model for brain ischemic preconditioning.
- Western immunoblotting was used to assay total and phosphorylated ERK1/2 (p-ERK1/2) levels in the CA1 hippocampus.
- L-NAME, a nitric oxide synthase inhibitor, was administered 30 minutes prior to preconditioning.
Main Results:
- Total ERK1/2 protein levels remained unchanged post-preconditioning.
- Phospho-ERK1/2 levels significantly increased at various time points after preconditioning (5 min to 5 days).
- L-NAME administration significantly attenuated the preconditioning-induced increase in phospho-ERK1/2 levels.
Conclusions:
- Brain ischemic preconditioning promotes ERK1/2 phosphorylation, not de novo protein synthesis.
- The NO signaling pathway plays a partial role in mediating the phosphorylation of ERK1/2 induced by ischemic preconditioning.
- These findings highlight the involvement of NO-dependent ERK1/2 activation in the neuroprotective mechanisms of ischemic preconditioning.
Related Concept Videos
01:28Nitric Oxide Signaling Pathway
01:15Ischemic Stroke ll: Pathophysiology