Involvement of active vasoconstriction substances of sympathetic nervous system, endothelial cell dependent vasorelaxation substances and constriction substances of renin-angiotensin system in blood pressure suppression by oral administration of Camu-Camu (Myrciaria dubia) fruit juice was investigated. Wister-Kyoto rats (WKY) and SHR were used and divided into WKYW and SHRW groups given by water, and WKYC and SHRC groups given by Camu-Camu fruit juice 0.25mℓ (total polyphenol content 337μg, Vitamin C content 2.25mg). When measuring blood pressure by insertion method of carotid artery catheter, norepinephrine (NE) losartan and L-NAMA were orally administered and involvement of angiotensin II and endothelial nitric oxide synthase (eNOS) in blood pressure suppression was evaluated. In administration of orally Losartan, blood pressure in SHRC was less increased than in SHRW, suggesting that those except for angiotensin ATII involved blood pressure suppression. Blood pressure of SHRC was significantly increased as compared with that of SHRW. Response of removed thoracic aorta to NE, acethylcoline, phenylphrine (PHE) in Kerbs ringer liquid was examined. Vasoconstrictive response elicited from active substances of sympathetic nervous systems showed more desensitization in SHRC than SHRW and vasorelaxation response elicited from endothelial dependent relaxation substances was accelerated. Blood pressure measurement by insertion method of catheter and tension measurement of removed thoracic aorta revealed the enhancement of eNOS in SHR by oral administration of Camu-Camu fruit juice.
