Serotonin 5-hT1A receptor activation prevents phosphorylation of NMDA receptor NR1 subunit in cerebral ischemia.
The mechanisms involved in the neuroprotective effect of serotonin 5-HT1A receptor agonists on brain damage induced by ischemia remain to be fully elucidated. Given that serotonergic drugs may regulate N-methyl-D-aspartate (NMDA) receptor function, which is implicated in events leading to ischemia-induced neuronal cell death, this study sought to determine the effects of the selective 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), on the levels of NMDA receptor NR1 subunit in gerbil hippocampus after transient global cerebral ischemia. Pretreatment with 8-OH-DPAT (1 mg/kg) prevented the neuronal loss in CA1 subfield 72 h after ischemia. NMDA receptor NR1 levels in whole hippocampus were not affected 24 h after ischemia, but the levels of the subunit phosphorylated at the protein kinase A (PKA) site, pNR1(Ser897), were significantly increased, and this increase was prevented by the same 8-OH-DPAT dose, a probable consequence of the increased phosphatase 1 (PP1) enzyme activity found in ischemic gerbils pretreated with the 5-HT1A receptor agonist. The results suggest that NR1 subunit phosphorylation plays a role in the neuroprotective effect of 8-OH-DPAT on cell damage induced by global cerebral ischemia in the gerbil hippocampus and support the potential interest of 5-HT1A receptor activation in the search for neuroprotective strategies.
Salazar-Colocho
P
P
Division of Neuroscience, CIMA, University of Navarra, Av. Pío XII 55, 31008, Pamplona, Spain.
Del Río
J
J
Frechilla
D
D
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D005849:Gerbillinae; D006624:Hippocampus / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000188:drug therapy / Q000503:physiopathology*; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D054645:Protein Phosphatase 1 / Q000378:metabolism; D044282:Receptor, Serotonin, 5-HT1A / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*
C409466:NR1 NMDA receptor; D018696:Neuroprotective Agents; D016194:Receptors, N-Methyl-D-Aspartate; D044282:Receptor, Serotonin, 5-HT1A; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D054645:Protein Phosphatase 1