Mt. Hsieh et al., MAGNOLOL DECREASES BODY-TEMPERATURE BY REDUCING 5-HYDROXYTRYPTAMINE RELEASE IN THE RAT HYPOTHALAMUS, Clinical and experimental pharmacology and physiology, 25(10), 1998, pp. 813-817
1, The effects of magnolol, isolated and purified from the cortex of M
agnolia officinalis Rehd, et Wils, on thermoregulation and hypothalami
c release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were
assessed in normothermic rats and in febrile rats treated with interle
ukin-1 beta. 2, Intraperitoneal administration of magnolol (25-100 mg/
kg) produced a decrease in colon temperature, an increase in foot skin
temperature, a decrease in metabolic rate and a decrease in the endog
enous release of 5-HT in the rat hypothalamus, 3, Depletion of rat bra
in 5-HT, produced by intracerebroventricular pretreatment with 5,7-dih
ydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneo
us vasodilation and decreased metabolism, 4, Intracetebroventricular a
dministration of (+/-)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT2 recept
or agonist; 5-10 mu g/5 mu L) increased basal colon temperature and re
versed the magnolol-induced hypothermia. 5, The increases in both colo
n temperature and hypothalamic 5-HT release produced by interleukin-1
beta injection were attenuated by treatment with magnolol, 6, The data
suggest that magnolol decreases body temperature (due to increased he
at loss and decreased heat production) by reducing 5-HT release in rat
hypothalamus.