Antihypertensive effects of DL-tetrahydropalmatine: an active principle isolated from Corydalis.
1. The effects of DL-tetrahydropalmatine (DL-THP) on cardio-vascular function and hypothalamic release of monoamines were assessed in rats under urethane anaesthesia. 2. Intravenous administration of DL-THP (1-10 mg/kg) produced hypotension, bradycardia, a decrease in hypothalamic serotonin and noradrenaline release and an increase in hypothalamic dopamine release in rats. 3. Intrahypothalamic administration of DOI (a serotonergic 5-HT2 receptor antagonist) or apomorphine (a dopamine D2-receptor agonist) produced the opposite effects and reversed DL-THP-induced hypotension and bradycardia. 4. The data suggest that DL-THP acts through the 5-HT2 and/or D2-receptor antagonism in the hypothalamus to induce hypotension and bradycardia in rats.
Lin
M T
MT
Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan, ROC.
Chueh
F Y
FY
Hsieh
M T
MT
Chen
C F
CF
D000662:Amphetamines / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000959:Antihypertensive Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001600:Berberine Alkaloids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017207:Rats, Sprague-Dawley; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D000662:Amphetamines; D000959:Antihypertensive Agents; D001600:Berberine Alkaloids; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C014215:tetrahydropalmatine; D007650:Ketanserin; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine