[Effects of tetrandrine on hypertensive responses induced by electric stimulation and alpha-adrenoceptor agonists in pithed rats].
Tetrandrine (Tet) 5 mg.kg-1 i.v. inhibited the pressor action of norepinephrine (NE) release induced by electric stimulation (10 V, 0.5-16 Hz) of spinal cord T11-L2. However, Tet 5 mg.kg-1 ia did not obviously attenuate the hypertensive responses to NE 0.51-16.91 micrograms.kg-1 i.v., indicating that Tet did not affect the alpha 1-adrenoceptors-mediated vasoconstriction. Tet 5 mg.kg-1 ia decreased the pressor responses to NE 0.05 and 0.17 micrograms.kg-1 i.v. and markedly reduced the dose-dependent hypertensive responses to B-HT920 i.v., a selective alpha 2-adrenoceptor agonist, proving that Tet reduced alpha 2-adrenoceptors-mediated vasoconstriction.
Department of Pharmacology, Second Military Medical University, Shanghai, China.
C Y
CY
Miao
F L
FL
Zhang
Q Y
QY
Zhu
K H
KH
Zhang
D F
DF
Su
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001381:Azepines / Q000494:pharmacology*; D044182:Benzylisoquinolines; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology; D014661:Vasoconstriction / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000470:Alkaloids; D000959:Antihypertensive Agents; D001381:Azepines; D044182:Benzylisoquinolines; D011942:Receptors, Adrenergic, alpha; C009438:tetrandrine; C024763:talipexole; D009638:Norepinephrine