[The cardiovascular reactions mediated by TPA and tamoxifen in spinal cord of conscious rats].
Intrathecal administration (ith) of phorbol 12-myristate (TPA), an activator of protein kinase C, (31.24, 26.5, 125 and 250 ng/10 micrograms) to conscious rats produced a marked dose-dependent pressor effect without significant change in heart rate (HR). Intrathecal administration of tamoxifen (3.125, 6.5 and 100 micrograms/10 microliters), one of the inhibitors of protein kinase C, produced a marked dose-dependent hypotensive effect. Intrathecal injection of exogenous DBcAMP (12.5, 25, 50 and 100 micrograms/10 microliters) also increased the mean arterial blood pressure (mABP) and markedly lowered HR. It was further observed that, based on the effect of DBcAMP (25 micrograms/10 microliters), the pressor effect of four doses of TPA can be augmented. The results indicate that TPA in spinal cord may exert hypertensive effect via activation of PKC and tamoxifen may exert a hypotensive effect via inhibition of PKC. In addition, the pressor effect of TPA could be augmented by preadministration of DBcAMP.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003994:Bucladesine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D007278:Injections, Spinal; D008297:Male; D011493:Protein Kinase C / Q000819:agonists / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar; D013629:Tamoxifen / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D013629:Tamoxifen; D003994:Bucladesine; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate