Mt. Lin et al., ANTIHYPERTENSIVE EFFECTS OF DL-TETRAHYDROPALMATINE - AN ACTIVE PRINCIPLE ISOLATED FROM CORYDALIS, Clinical and experimental pharmacology and physiology, 23(8), 1996, pp. 738-742
1. The effects of DL-tetrahydropalmatine (DL-THP) on cardiovascular fu
nction and hypothalamic release of monoamines were assessed in rats un
der urethane anaesthesia. 2. Intravenous administration of DL-THP (1-1
0 mg/kg) produced hypotension, bradycardia, a decrease in hypothalamic
serotonin and noradrenaline release and an increase in hypothalamic d
opamine release in rats. 3. Intrahypothalamic administration of DOI (a
serotonergic 5-HT2 receptor antagonist) or apomorphine (a dopamine D-
2-receptor agonist) produced the opposite effects and reversed DL-THP-
induced hypotension and bradycardia. 4. The data suggest that DL-THP a
cts through the 5-HT2 and/or D-2-receptor antagonism in the hypothalam
us to induce hypotension and bradycardia in rats.