Abstract
Aim The effect of 8 weeks′ streptozotocin (STZ)-
induced diabetes and aminoguanidine (AMNG), the
inhibitor of advanced glycosylation reaction, treatment
on arteriolar reactivity to vasoactive substances
was investigated in vitro.Materials and Methods Studies were performed in
untreated control rats (n = 10), STZ-induced (60 mg/kg
i.v.) diabetic rats (n = 10), AMNG-treated (600 mg/l
given in drinking water throughout 8 weeks) control
rats (n = 10) and AMNG-treated (600 mg/l given in
drinking water, beginning at 72h after STZ and
throughout 8 weeks of diabetes) diabetic rats (n = 10).
Results are expressed as the mean ±s.e. Relaxant
responses are expressed as a percentage (%) relaxation
of noradrenaline-induced tone. Statistical comparisons
were made by one-way analysis of variance
(ANOVA) followed by Tukey–Kramer multiple
comparisons test.Results 1. The decreased body weights (205 ± 6 g)
and increased blood glucose levels (583 ± 8 mg/dl) of
diabetic rats were partially restored by treatment of
aminoguanidine (253 ± 6 g, p < 0.05 and 480 ± 14 mg/dl, p < 0.001, respectively). 2. Diabetes caused a 71%
deficit in maximal endothelium-dependent relaxation
to acetylcholine for noradrenaline precontracted
aortas (p < 0.001). AMNG treatment prevented the
diabetes-induced impairment in endothelium dependent
relaxation (58 ± 8%) to acetylcholine, maximum
relaxation remaining in the non-diabetic range
(78 ± 4%). 3. Neither diabetes nor treatment affected endothelium-independent relaxation (