Objectives: Pituitary adenylate cyclase activating polypeptide (PACAP) is a neuropeptide with diverse effects, including neuroprotective actions. The aim of the present study was to provide evidence that PACAP is neuroprotective against monosodium glutamate (MSG)-induced retinal degeneration through the involvement of antiapoptotic signaling pathways. Methodology: Newborn Wistar rat pups were injected with 2 mg/g MSG s.c. on postnatal days 3, 5 and 9. PACAP was given unilaterally into the vitreous body. Retinas were removed at 3 weeks of age and processed for light and electronmicroscopical histological examination. In another series of experiments, retinas were removed 12 and 24 hours after the MSG and PACAP treatments and were processed for Western blot analysis. Results: MSG treatment led to a nearly total degeneration of the inner retinal layers, which was significantly attenuated by 100 pmol PACAP. Western blot analysis revealed that PACAP increased the levels of the antiapoptotic phospho-ERK and CREB and phospho-Bad, and reduced the proapoptotic signaling molecules such as JNK, AIF, cytochrome-c and caspase-3. Conclusion: Our results provide evidence that PACAP is protective against MSG-induced retinal degeneration in newborn rats. This protective effect is due, at least partly, to the induction of antiapoptotic and inhibition of proapoptotic signaling pathways.
|Number of pages||7|
|Journal||International Journal of Neuroprotection and Neuroregeneration|
|Publication status||Published - Jun 1 2006|
ASJC Scopus subject areas
- Clinical Neurology