Abstract
Apoptosis and glutamate-mediated excitotoxicity may play a role in the pathogenesis of many neurodegenerative disorders, including Parkinson's disease (PD). In the present study, we investigated whether stimulation of the 5-hydroxytryptamine 1A (5-HT1A) receptor attenuates N-methyl-d-aspartate- (NMDA) and 1-methyl-4-phenylpyridinium (MPP+)-induced apoptotic cell death in cell culture models. A brief exposure (20 min) of M213-2O striatal cells to NMDA and glutamate produced a delayed increase in caspase-3 activity and DNA fragmentation in a dose- and time-dependent manner. NMDA-induced caspase-3 activity and DNA fragmentation were almost completely blocked by the 5-HT1A agonists 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) and (R)-5-fluoro-8 hydroxy-2-(dipropylamino)-tetralin (R-UH-301). Additionally, the protective effects of 8-OH-DPAT and R-UH-301 on NMDA-induced caspase-3 activation and apoptosis were reversed by pretreatment with the 5-HT1A antagonists N-[2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl]-N-(2-pyridinyl) cyclohexane carboxamide (WAY 100635) and S-UH-301, respectively. Similarly, dose- and time-dependent increases in caspase-3 activity and DNA fragmentation were observed in rat primary mesencephalic neurons after a brief exposure to NMDA and glutamate. Caspase-3 activation and DNA fragmentation in primary mesencephalic neurons were almost completely inhibited by 8-OH-DPAT. This neuroprotective effect of 8-OH-DPAT was reversed by WAY 100635. Additionally, 8-OH-DPAT blocked tyrosine hydroxylase (TH)-positive cell death after NMDA exposure and also almost completely attenuated the NMDA-induced Ca2+ influx in primary mesencephalic cultures. Furthermore, 8-OH-DPAT andR-UH-301 blocked apoptotic cell death in the primary mesencephalic neurons that were exposed to the Parkinsonian toxin MPP+. Together, these results suggest that 5-HT1A receptor stimulation may be a promising pharmacological approach in the development of neuroprotective agents for PD.
Footnotes
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This work was supported by the National Institute of Neurological Disorders and Stroke Grant R01-NS38644.
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DOI: 10.1124/jpet.102.044370
- Abbreviations:
- PD
- Parkinson's disease
- NMDA
- N-methyl-d-aspartate
- 5-HT1A
- 5-Hydroxy-tryptamine-1A
- MPP+
- 1-methyl-4-phenylpyridinium
- 8-OH-DPAT
- 8-hydroxy-2-(di-n-propylamino)-tetralin
- UH-301
- 5-fluoro-8 hydroxy-2-(dipropylamino)-tetralin
- WAY 100635
- N-[2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl]-N-(2-pyridinyl) cyclohexane carboxamide
- Z-DEVD-FMK
- Z-Asp-Glu-Val-Asp-fluromethyl ketone
- Ac-DEVD-AMC
- acetyl-Asp-Glu-Val-Asp-7-amino-4-methyl-coumarin
- FITC
- fluorescein isothiocyanate
- AM
- acetoxymethyl ester
- TH
- tyrosine hydroxylase
- PBS
- phosphate-buffered saline
- ELISA
- enzyme-linked immunosorbent assay
- caspase
- cysteine-aspartate protease
- EBSS
- Earle's balanced salt solution
- MK-801
- (±)-5-methyl-10,11-dihydro-5H-dibenzo-cyclohepten-5,10-imine-maleate
- ABTS
- 2,2′-azino-di-(3-ethylbenzthiazoline sulfonate (6)) diammonium salt
- MAPK
- mitogen-activated protein kinase
- Received September 12, 2002.
- Accepted November 15, 2002.
- U.S. Government
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