Microinjection of resveratrol into rostral ventrolateral medulla decreases sympathetic vasomotor tone through nitric oxide and intracellular Ca2+ in anesthetized male rats.
OBJECTIVE
To define the effect of resveratrol (RES) on the central regulation of blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA).


METHODS
RES was microinjected into the rostral ventrolateral medulla (RVLM), and BP, HR, and RSNA were recorded simultaneously in anesthetized rats.


RESULTS
A microinjection of RES (20, 40, and 80 micromol/L, 0.2 microL) into the RVLM dose dependently decreased BP, HR, and RSNA. Pretreatment with an anti-estrogen tamoxifen (100 micromol/L, 0.2 microL) did not affect the effects of RES. Pretreatment with NG-nitro- L-arginine methyl ester (100 micromol/L, 0.2 microL), an inhibitor of nitric oxide (NO) synthase, could completely abolish the effect of RES. A prior microinjection of Bay K8644 (500 nmol/L, 0.2 microL), an agonist of calcium channels, could also abrogate the effect of RES. Prior administration of a potent inhibitor of tyrosine phosphatase, sodium orthovanadate (1 mmol/L, 0.2 microL), could partially attenuate the inhibitory effect of RES.


CONCLUSIONS
The results suggest that a microinjection of RES into the RVLM inhibits BP, HR, and RSNA. The effects may be mediated by NO synthesis and a decrease in Ca2+ influx, in which protein tyrosine kinase is involved.
Ma
Hui-juan
HJ
Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China.
Cao
Ya-kun
YK
Liu
Yi-xian
YX
Wang
Ru
R
Wu
Yu-ming
YM
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D020013:Calcium Signaling / Q000187:drug effects*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008845:Microinjections; D009129:Muscle Tonus / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000294:innervation; D009569:Nitric Oxide / Q000502:physiology*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000187:drug effects; D000077185:Resveratrol; D013267:Stilbenes / Q000008:administration & dosage / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000187:drug effects*
D004791:Enzyme Inhibitors; D013267:Stilbenes; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D000077185:Resveratrol