Aortic response to relaxing agents in Watanabe heritable hyperlipidemic (WHHL) rabbits of different age.
Serum and aortic tissue cholesterol levels in parallel with aortic relaxation to endothelium-dependent and independent drugs were determined in Watanabe heritable hyperlipidemic (WHHL) rabbits in comparison with New Zealand (N.Z.) normocholesterolemic rabbits, aged 4-14 months. Serum cholesterol was elevated (626 +/- 99 mg/100 ml) in 4-6-month-old WHHL rabbits and significantly lower in 12-14-month-old animals (344 +/- 51 mg/100 ml). Cholesterol infiltration in thoracic aorta was high in young WHHL compared with N.Z. rabbits (0.88 +/- 0.3 mg/100 mg fresh tissue vs. 0.08 +/- 0.003 mg/100 mg, respectively) and it did not vary with age. In N.Z. rabbits, serum and aortic cholesterol levels were low from 4 to 14 months of age. The aortic relaxation to acetylcholine (0.03-3 microM) on EC50 noradrenaline precontracted rings was similar in 4-6-month-old WHHL and N.Z. rabbits of the same age. In WHHL rabbits, the relaxation to acetylcholine was significantly reduced in 7-11- (-35% at maximum) and in 12-14-month-old rabbits (-40% at maximum). In N.Z. rabbits the response to acetylcholine was not modified in the 3 age groups. The relaxation to ATP (30 microM to 3 mM) was reduced by age both in N.Z. and in WHHL rabbits, but in 12-14-month-old WHHL rabbits the maximal relaxing response was significantly more elevated than in age-matched N.Z. rabbits (50.1 +/- 2.5% vs. 35.1 +/- 3.2%, respectively). The aortic relaxation to NaNO2 (10 microM to 3 mM) was reduced by age both in N.Z. and in WHHL rabbits.(ABSTRACT TRUNCATED AT 250 WORDS)
Chinellato
A
A
Department of Pharmacology, University of Padova, Italy.
Banchieri
N
N
Pandolfo
L
L
Ragazzi
E
E
Froldi
G
G
Norido
F
F
Caparrotta
L
L
Fassina
G
G
D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000367:Age Factors; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D002784:Cholesterol / Q000097:blood / Q000378:metabolism; D005260:Female; D006949:Hyperlipidemias / Q000097:blood / Q000235:genetics / Q000503:physiopathology*; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D011817:Rabbits; D012977:Sodium Nitrite / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood
D014280:Triglycerides; D000255:Adenosine Triphosphate; D002784:Cholesterol; D012977:Sodium Nitrite; D000109:Acetylcholine; D009638:Norepinephrine