Blockade of 5-HT(3) receptor with MDL 72222 and Y 25130 reduces beta-amyloid protein (25--35)-induced neurotoxicity in cultured rat cortical neurons.
The present study was performed to examine neuroprotective effects of 5-hydroxytryptamine (5-HT)(3) receptor antagonists against beta-amyloid protein (25--35)-, a synthetic 25--35 amyloid peptide, induced neurotoxicity using cultured rat cortical neurons. beta-Amyloid protein (25--35) produced a concentration-dependent reduction of cell viability, which was significantly reduced by (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine (MK-801), an N-methyl-d-aspartate (NMDA) receptor antagonist, verapamil, an L-type Ca(2+) channel blocker, and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor. The 5-HT(3) receptor antagonists, tropanyl-3,5-dichlorobenzoate (MDL-72222, 0.1--10 microM) and N-(1-azabicyclo[2.2.2.]oct-3-yl)-6-chloro-4-ethyl-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-8-carboxamide hydrochloride (Y 25130, 0.05--5 microM), decreased the beta-amyloid protein (25--35) (10 microM)-induced neuronal cell death as assessed by a colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and the number of apoptotic nuclei, evidenced by Hoechst 33342 staining. MDL 72222 and Y 25130 inhibited the beta-amyloid protein (25--35) (10 microM)-induced elevation of cytosolic Ca(2+) concentration ([Ca(2+)](c)) and glutamate release, generation of reactive oxygen species, and caspase-3 activity. These neuroprotective effects of MDL 72222 (10 microM) and Y 25130 (5 microM) were completely blocked by the simultaneous treatment with 100 microM 1-phenylbiguanide, a 5-HT(3) receptor agonist, indicating that the protective effects of these compounds were due to 5-HT(3) receptor blockade. These results suggest that the activation of the 5-HT(3) receptor may be partially involved in beta-amyloid protein-induced neurotoxicity, by membrane depolarization for Ca(2+) influx. Therefore, the blockade of 5-HT(3) receptor with MDL 72222 and Y 25130, may ameliorate the beta-amyloid protein-induced neurotoxicity by interfering with the increase of [Ca(2+)](c), and then by inhibiting glutamate release, generation of reactive oxygen species and caspase-3 activity.
Ju Yeon Ban
College of Veterinary Medicine and Research Institute of Herbal Medicine, Chungbuk National University, 12, Gaesin-dong, Heungduk-Gu, Cheongju, Chungbuk 361-763, Republic of Korea.
Yeon Hee Seong
D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors* / Q000633:toxicity; D000818:Animals; D001645:Biguanides / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000196:embryology; D004305:Dose-Response Relationship, Drug; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010078:Oxazines / Q000494:pharmacology*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors* / Q000633:toxicity; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D044406:Receptors, Serotonin, 5-HT3 / Q000378:metabolism; D058831:Serotonin 5-HT3 Receptor Antagonists; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D014326:Tropanes / Q000494:pharmacology*
D016229:Amyloid beta-Peptides; D001645:Biguanides; D019086:Bridged Bicyclo Compounds, Heterocyclic; D018696:Neuroprotective Agents; D010078:Oxazines; D010446:Peptide Fragments; D017382:Reactive Oxygen Species; D044406:Receptors, Serotonin, 5-HT3; D058831:Serotonin 5-HT3 Receptor Antagonists; D017366:Serotonin Receptor Agonists; D014326:Tropanes; C074636:amyloid beta-protein (25-35); D018698:Glutamic Acid; C070671:azasetron; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases; C042253:bemesetron; D002118:Calcium; C008846:phenyl biguanide