Prevention of delayed neuronal cell death by PACAP and its molecular mechanism.

Accession number;04A0322988
Title;Prevention of delayed neuronal cell death by PACAP and its molecular mechanism.
Author; SHIODA SEIJI (Showa Univ., School of Medicine, JPN) OTAKI HIROKAZU (Showa Univ., School of Medicine, JPN) SUZUKI RYUSUKE (Showa Univ., School of Medicine, JPN) NAKAMACHI TOMOYA (Showa Univ., School of Medicine, JPN) TAKENOYA FUMIKO (Showa Univ., School of Medicine, JPN) DOHI KENJI (Showa Univ., JPN) NAKAJO SHIGEO (Showa Univ., School of Pharm. Sci., JPN)
Journal Title;Folia Pharmacologica Japonica
Journal Code:G0740A
ISSN:0015-5691
VOL.123;NO.4;PAGE.243-252(2004)
Figure&Table&Reference;FIG.7, REF.24
Pub. Country;Japan
Language;Japanese
Abstract;Ischemic delayed neuronal cell death (apoptosis) in the hippocampus is prevented by PACAP. PACAP inhibits the increasing activity of the MAP kinase family, especially on JNK/SAPK and p38, thereby protecting against apoptotic cell death. After the ischemia-reperfusion, both pyramidal cells and astrocytes increased their expression of PACAP receptors (PAC1-Rs). The pyramidal cells degenerated but reactive astrocytes increased their expression of PAC1-R. PACAP does not only inhibit apoptotic cell death directly, but also affects astrocytes through PAC1-Rs. Interleukin-6 (IL-6), produced in astrocytes, has several effects on the prevention of brain ischemia and trauma and stimulating neuronal growth. IL-6 secretion into the CSF was markedly stimulated after PACAP infusion, suggesting that PACAP stimulates IL-6 secretion from astrocytes. We studied the effects of PACAP on the wild type and IL-6 KO mice after brain ischemia. In wild-type animals, PACAP significantly inhibited cell death, but in IL-6 KO animals, no cytoprotective effect of PACAP was seen. These results suggest that PACAP inhibits apoptotic cell death partly through IL-6. It is considered that PACAP itself and IL-6, stimulated secretion by PACAP, both synergistically inhibit the JNK/SAPK and p38 signaling pathway, thereby protecting against neuronal cell death. (author abst.)
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