Magnolol decreases body temperature by reducing 5-hydroxytryptamine release in the rat hypothalamus.
1. The effects of magnolol, isolated and purified from the cortex of Magnolia officinalis Rehd. et Wils, on thermoregulation and hypothalamic release of 5-hydroxytryptamine (5-HT) by in vivo microdialysis were assessed in normothermic rats and in febrile rats treated with interleukin-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 endogenous release of 5-HT in the rat hypothalamus. 3. Depletion of rat brain 5-HT, produced by intracerebroventricular pretreatment with 5,7-dihydroxytryptamine, attenuated the magnolol-induced hypothermia, cutaneous vasodilation and decreased metabolism. 4. Intracerebroventricular administration of (+/-)-2,5-dimethoxy-4-iodoamphetamine (a 5-HT2 receptor agonist; 5-10 micrograms/5 microL) increased basal colon temperature and reversed the magnolol-induced hypothermia. 5. The increases in both colon 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 heat loss and decreased heat production) by reducing 5-HT release in rat hypothalamus.
Institute of Chinese Pharmaceutical Sciences, China Medical College, Taichung City.
M T
MT
Hsieh
F Y
FY
Chueh
M T
MT
Lin
D000818:Animals; D001713:Biphenyl Compounds / Q000302:isolation & purification / Q000494:pharmacology*; D001833:Body Temperature Regulation / Q000187:drug effects*; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D003106:Colon; D015536:Down-Regulation; D007031:Hypothalamus / Q000187:drug effects* / Q000502:physiology; D007375:Interleukin-1 / Q000494:pharmacology; D017705:Lignans; D008297:Male; D010946:Plants, Medicinal / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000032:analysis / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology; D012867:Skin
D001713:Biphenyl Compounds; D002492:Central Nervous System Depressants; D007375:Interleukin-1; D017705:Lignans; D012702:Serotonin Antagonists; C005498:magnolol; D012701:Serotonin