Effects of memantine on soluble Alphabeta(25-35)-induced changes in peptidergic and glial cells in Alzheimer's disease model rat brain regions.
Soluble forms of amyloid-beta (Abeta) have been considered responsible for cognitive dysfunction prior to senile plaque formation in Alzheimer's disease (AD). As its mechanism is not well understood, we examined the effects of repeated i.c.v. infusion of soluble Alphabeta(25-35) on peptidergic system and glial cells in the pathogenesis of AD. The present study aims to investigate the protective effects of memantine on Abeta(25-35)-induced changes in peptidergic and glial systems. Infusion of Alphabeta(25-35) decreased the level of immunoreactive somatostatin (SS) and substance P (SP) in the hippocampus prior to neuronal loss or caspase activation, which is correlated with the loss of spine density and activation of inducible nitric-oxide synthase (iNOS). Biochemical experiment with peptide-degrading enzymes, prolyl oligopeptidase (POP) and endopeptidase 24.15 (EP 24.15) activities demonstrated a concomitant increase with the activation of glial marker proteins, glial fibrillary acidic protein (GFAP) and CD11b in the Abeta-treated hippocampus. Double immunostaining experiments of EP 24.15 and GFAP/CD11b antibodies clearly demonstrated the co-localization of neuro peptidases with astrocytes and microglia. Treatment with memantine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist significantly attenuated Abeta(25-35)-induced changes of neuropeptides, their metabolizing enzymes, glial marker proteins, and activation of iNOS. Taken together, the data implies that memantine exerts its protective effects by modulating the neuropeptide system as a consequence of suppressing the glial cells and oxidative stress in AD model rat brain regions.
Arif
M
M
Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan. marif@univdhaka.edu
Chikuma
T
T
Ahmed
Md M
MM
Nakazato
M
M
Smith
M A
MA
Kato
T
T
D000544:Alzheimer Disease / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000633:toxicity; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D018845:CD11 Antigens / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology / Q000627:therapeutic use; D005904:Glial Fibrillary Acidic Protein / Q000187:drug effects / Q000378:metabolism; D005911:Gliosis / Q000188:drug therapy / Q000503:physiopathology / Q000517:prevention & control; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008559:Memantine / Q000494:pharmacology* / Q000627:therapeutic use; D009410:Nerve Degeneration / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism; D009479:Neuropeptides / Q000187:drug effects* / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000633:toxicity; D010447:Peptide Hydrolases / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013004:Somatostatin / Q000187:drug effects / Q000378:metabolism; D013373:Substance P / Q000187:drug effects / Q000378:metabolism
D016229:Amyloid beta-Peptides; D015415:Biomarkers; D018845:CD11 Antigens; D018691:Excitatory Amino Acid Antagonists; D005904:Glial Fibrillary Acidic Protein; D009479:Neuropeptides; D010446:Peptide Fragments; C074636:amyloid beta-protein (25-35); D013373:Substance P; D013004:Somatostatin; D052247:Nitric Oxide Synthase Type II; D010447:Peptide Hydrolases; D008559:Memantine