Atorvastatin causes depressor and sympatho-inhibitory effects with upregulation of nitric oxide synthases in stroke-prone spontaneously hypertensive rats.
OBJECTIVE
Recent studies have suggested that statins decrease blood pressure in hypertensive animals and upregulate endothelial nitric oxide synthase (eNOS) expression. However, the effects of statins on the expression of nitric oxide synthase (NOS) in the brain and the sympathetic nervous system remain to be elucidated. The aim of this study was thus to examine the effects of atorvastatin on blood pressure, sympathetic nerve activity, and the expression of NOS in stroke-prone spontaneously hypertensive rats (SHRSP) as well as in Wistar-Kyoto (WKY) rats.


METHODS
The animals received atorvastatin (50 mg/kg per day) for 30 days. Systolic blood pressure and heart rate were evaluated using the tail-cuff method. Urinary norepinephrine excretion was measured for 24 h. The expression of eNOS, neuronal NOS (nNOS), and inducible NOS (iNOS) in the brain (cortex, cerebellum, hypothalamus and brainstem), aorta and heart were determined by Western blot analysis.


RESULTS
Systolic blood pressure and 24-h urinary norepinephrine excretion were significantly decreased in SHRSP, but not in WKY, after the treatment with atorvastatin. The eNOS and iNOS expression in the brain and aorta was significantly increased in atorvastatin-treated SHRSP and WKY. However, the nNOS expression in the brain was not altered in the atorvastatin-treated group.


CONCLUSIONS
These results suggest that atorvastatin decreases blood pressure, at least in part via the reduction of sympathetic nervous system activity in SHRSP. They also suggest that this sympatho-inhibitory effect may be mediated by an increase in NO production, with the upregulation of eNOS expression in the brain.
Kishi
Takuya
T
Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
Hirooka
Yoshitaka
Y
Mukai
Yasushi
Y
Shimokawa
Hiroaki
H
Takeshita
Akira
A
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000201:enzymology; D000069059:Atorvastatin; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000201:enzymology; D020022:Genetic Predisposition to Disease; D006339:Heart Rate / Q000187:drug effects; D006538:Heptanoic Acids / Q000494:pharmacology*; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D006973:Hypertension / Q000201:enzymology / Q000235:genetics / Q000503:physiopathology*; D007527:Isoenzymes / Q000378:metabolism; D008055:Lipids / Q000097:blood; D008297:Male; D009206:Myocardium / Q000201:enzymology; D009433:Neural Inhibition; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009638:Norepinephrine / Q000652:urine; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D011918:Rats, Inbred SHR / Q000235:genetics / Q000378:metabolism; D011921:Rats, Inbred WKY; D020521:Stroke / Q000235:genetics*; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D015854:Up-Regulation
D000959:Antihypertensive Agents; D006538:Heptanoic Acids; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D007527:Isoenzymes; D008055:Lipids; D011758:Pyrroles; D000069059:Atorvastatin; D019001:Nitric Oxide Synthase; D009638:Norepinephrine