title: Agonist stimulation of the serotonin1A receptor causes suppression of anoxia-induced apoptosis via mitogen-activated protein kinase in neuronal HN2-5 cells.
abstract: Previous studies have indicated that stimulation of neuronal inhibitory receptors, such as the serotonin1A receptor (5-HT1A-R), could cause attenuation of the activity of both N-type Ca2+ channels and N-methyl-D-aspartic acid receptors, thus resulting in protection of neurons against excitotoxicity. The purpose of this study was to investigate if the 5-HT1A-R is also coupled to an alternative pathway that culminates in suppression of apoptosis even in cells that are deficient in Ca2+ channels. Using a hippocampal neuron-derived cell line (HN2-5) that is Ca2+ channel-deficient, we demonstrate here that an alternative pathway is responsible for 5-HT1A-R-mediated protection of these cells from anoxia-triggered apoptosis, assessed by deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL). The 5-HT1A-R agonist-evoked protection was eliminated in the presence of pertussis toxin and also required phosphorylation-mediated activation of mitogen-activated protein kinase (MAPK), as evidenced by the elimination of the agonist-elicited rescue of neuronal cells by the MAPK kinase inhibitor PD98059 but not by the phosphatidylinositol 3-kinase (PI-3K) inhibitor wortmannin. Furthermore, agonist stimulation of the 5-HT1A-R caused a 60% inhibition of anoxia-stimulated caspase 3-like activity in the HN2-5 cells, and this inhibition was abrogated by PD98059 but not by wortmannin. Although agonist stimulation of the 5-HT1A-R caused an activation of PI-3Kgamma in HN2-5 cells, our results showed that this PI-3Kgamma activity was not linked to the 5-HT1A-R-promoted regulation of caspase activity and suppression of apoptosis. Thus, in the neuronal HN2-5 cells, agonist binding to the 5-HT1A-R results in MAPK-mediated inhibition of a caspase 3-like enzyme and a 60-70% suppression of anoxia-induced apoptosis through a Ca2+ channel-independent pathway.
authors: Department of Chemistry and CSI/IBR Center for Developmental Neuroscience, City University of New York at the College of Staten Island, 10314, USA.
authors: T
authors: T
authors: Adayev
authors: Y
authors: Y
authors: El-Sherif
authors: M
authors: M
authors: Barua
authors: N J
authors: NJ
authors: Penington
authors: P
authors: P
authors: Banerjee
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology; D000860:Hypoxia / Q000503:physiopathology*; D020287:In Situ Nick-End Labeling; D007295:Inositol Phosphates / Q000096:biosynthesis; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D009474:Neurons / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology; D009842:Oligopeptides / Q000494:pharmacology; D018408:Patch-Clamp Techniques; D010879:Piperazines / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D011985:Receptors, Serotonin / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D015853:Cysteine Proteinase Inhibitors; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D005419:Flavonoids; D007295:Inositol Phosphates; D008565:Membrane Proteins; D009842:Oligopeptides; D010879:Piperazines; D011725:Pyridines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C099158:acetyl-aspartyl-glutamyl-valyl-aspartal; C096429:L 709049; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium; D000077191:Wortmannin