Mc. Paredescarbajal et al., EFFECTS OF DIETARY SPIRULINA-MAXIMA ON VASOMOTOR RESPONSES OF AORTA RINGS FROM RATS FED A FRUCTOSE-RICH DIET, Nutrition research, 18(10), 1998, pp. 1769-1782
The effects of dietary Spirulina on vasomotor responses of aorta rings
from male Wistar rats fed a purified fructose-rich diet were analyzed
. For this purpose, the animals were allocated to one of three groups.
Group A received 60% glucose, group B received 60% fructose and group
C received, in addition to 60% fructose, 5% Spirulina. All animals we
re fed (20g/day/rat) the experimental diets for six weeks. Vasomotor r
esponses were evaluated by concentration-response (CR) curves to pheny
lephrine (PE) and to carbamoylcholine (CCh) of aorta rings with and wi
thout endothelium. Rings with endothelium from fructose-fed rats devel
oped more tension in response to PE and relaxed significantly less in
response to CCh than corresponding rings from rats of group A. In the
former rings, indomethacin-induced inhibition of cyclooxygenase decrea
sed significantly the PE-induced tension development and enhanced sign
ificantly the CCh-induced relaxation. Rings with endothelium from rats
of group C showed, relative to corresponding rings from group B, a ri
ghtward shift of the CR curve to PE and a significant decrease in the
maximum PE-induced tension development. In comparison to rings with en
dothelium from group B, corresponding rings from group C showed both a
significant leftward shift of the CR curve to CCh and a significant i
ncrease in the maximum percent of the CCh-induced relaxation. No signi
ficant differences were observed in the CR curves to these agonists of
rings without endothelium from either group. These results suggest th
at dietary fructose increases both the basal and the muscarinic recept
or-mediated synthesis/release of some cyclooxygenase-dependent vasocon
stricting metabolites of arachidonic acid. These data also suggest, th
at dietary Spirulina is able to prevent these effects of fructose. (C)
1998 Elsevier Science Inc.