実験的家兎動脈硬化症の血管反応性について

抄録

This study was undertaken to examine the effect of hypercholesterolemia on contractile response of arteries to several vasoactive agents and transmural electrical stimulation. The isolated descending aorta, coronary and basilar arteries from 10 controls (C) and 6 hypercholesterolemic rabbits fedwith 1% cholesterol diet (CD) for 3 months, were cut into helical strip. The artery was suspended in tissue bath filled with oxygenated Krebs-Ringer solution and kept in 37°C. The strip was attached to force displacement transduser for recording the isometric force.
Contraction-developed tension to KCl, norepinephrine (NE), 5-hydroxytryptophan (5-HT), prostagrandin F_2α (PG) and histamine (His) was determined.
Maximum tension developed by KCl, NE, His was elevated in the basilar artery from CD rabbit (see Table 2). Median effective concentration (ED 50) for 5-HT was higher in the artery from CD rabbit. On the other hand, aorta from CD was supersensitive to His as demonstrated low ED 50. The results were shown in Table 3.
Tension developed by transmural electrical stimulation and passive tension were reduced in the aorta and the basilar artery from CD rabbit.
Responce to vasoactivators were somewhat different by site of arteries obteined. Maximum tension was as following order in both control and CD rabbit. Aorta; NE>His>KCl>PGF_2α>5-HT, coronary artery; His>PGF_2α>KCl>5-HT>NE, basilar artery; His>KCl>5-HT>NE>PGF_2α.
Influences of hypercholesterolemia to tension development by vasoactivators were similar in the three segments of the different parts.
Reduction of passive tension in arteries from CD rabbit revealed the loss of elasticity in CD rabbit arteties.
It may conclude that hypercholesterelemia induced supersensitivity to His and the change of response to vasoactivators of the arteries from hypercholesterolemic rabbits are due to the change of receptor function to vasoactivators and loss of elasticity due to ahterogenic process.