摘要
小檗碱(Ber)4mg/kg ⅳ使正常大鼠的血压(BP)降低,心率(HR)不变;迷走神经切断大鼠的BP降低,HR减慢;毁脊髓大鼠的HR减慢,BP不变。在离体豚鼠右心房,Ber产生负性变时作用,且不被阿托品对抗。Ber使异丙肾上腺素、组胺和CaCl_2正性变时作用的量效曲线非平行性右移,最大反应压低,呈非竞争性拮抗作用,其pD_2分别为4.82,4.51和4.68。结果表明Ber对正常大鼠的负性变时作用,可因其降压所致的反射性HR加快而抵消。Ber的负性变时作用可能与心肌M,β和H_2受体无关,也不是选择性阻滞Ca^(2+)内流所致。
Berberine sulfate (Ber) 4 mg / kg iv ered the blood pressure (BP) in the normal rats, redid not cause changes of the heart rate (HR) but low duced HR and diminished BP in the vagotomized rats, decreased HR and exerted no effect on BP in the pithed rats. In the isolated guinea pig right atria, Ber showed a negative chronotropic effect resistant to atropine. Ber shifted the cumulative concentration positive chronotropic action curves for isoprenaline, histamine and CaC12 to the right in a nonparallel manner, and depressed their maximal response with a pD2 value of 4.82, 4.51 and 4.68, respectively. The results suggested that the negative chronotropic effect of Ber 4 mg / kg in the normal rats was able to beabolished by the reflex acceleration of heart rate which was caused by its hypotensive action. The negative chronotropic effect of Ber was most likely to be in no association with cardiac M, β and H2 receptors and not to be brought about by the block of transsar colemmal influx of calcium through voltage-dependent calcium channel.
出处
《中国药理学与毒理学杂志》
CAS
CSCD
北大核心
1991年第1期12-15,共4页
Chinese Journal of Pharmacology and Toxicology
关键词
小檗碱
变时作用
berberine
atropine
isoprenaline
histamine
CaCl2
chronotropic effect
heart rate
