title: Modulatory effects of magnolol on potassium-stimulated 5-hydroxytryptamine release from rat cortical and hippocampal slices.
abstract: Magnolol, a phenolic constituent of magnolia bark, is a known central nervous system depressant. To examine the possibility that magnolol may elicit its depressant effect by modulating central serotonergic activity, its effect on 35 mM K(+)-stimulated 5-[3H]HT release from rat hippocampal and frontal cortical slices were examined. Inclusion of magnolol (1-100 microM) had no effect on 5-HT release in hippocampal slices but elicited a dose-related inhibition on 5-HT release from cortical slices. The inhibitory effect of magnolol on K(+)-stimulated 5-HT release from the cortex was not affected by either antagonists (metergoline, propranolol, and cyproheptadine) (0.01-10 microM) of various 5-HT receptor subtypes or the voltage-dependent sodium channel blocker tetrodotoxin (1 microM). It is concluded that the suppression of brain 5-HT release by magnolol is site-specific, and the suppression of cortical 5-HT release by magnolol is not via the 5-HT autoreceptors at the 5-HT terminals.
authors.affiliation: Department of Pharmacology, National Yang-Ming Medical College, Taipei, Taiwan, Republic of China.
authors.forename: T H
authors.initials: TH
authors.lastname: Tsai
authors.forename: T F
authors.initials: TF
authors.lastname: Lee
authors.forename: C F
authors.initials: CF
authors.lastname: Chen
authors.forename: L C
authors.initials: LC
authors.lastname: Wang
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D017705:Lignans; D008297:Male; D011188:Potassium / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D001713:Biphenyl Compounds; D017705:Lignans; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; C005498:magnolol; D012701:Serotonin; D011188:Potassium