Roberts A M, Messina E J, Kaley G
Prostaglandins. 1981 Apr;21(4):555-69. doi: 10.1016/0090-6980(81)90004-6.
Bovine coronary arterial strips (BCA) exhibiting spontaneous tone, relax in response to a decrease in the pO2 of the bathing medium. Experiments were performed to determine if prostaglandins (PGs) mediate the oxygen-induced changes in tension. BCA were equilibrated in Krebs-bicarbonate solution at 37 degrees C gassed with 95% O2, 5% CO2 and tension was measured isometrically. When the pO2 of the bathing medium was decreased, BCA exhibited reversible reductions in tension. Switching from 95% O2, 5% CO2 to 95% N2, 5% CO2 (anoxia) elicited an initial relaxation followed by a contraction. In contrast, a change to 5% O2, 5% CO2, 90% N2 (hypoxia) was followed by a sustained relaxation. Re-introduction of O2 to anoxic strips produced a biphasic response: relaxation followed by contraction. Indomethacin or eicosatetraynoic acid (EYA) increased tone and inhibited the relaxation produced by anoxia or hypoxia. Indomethacin or EYA did not inhibit the relaxation of anoxic strips during re-introduction of O2, but did inhibit the contraction partially. Relaxation of arterial strips to arachidonic acid (AA) was similar to relaxation to prostacyclin (PGI2). Anoxia limited the relaxation to AA but not to PGI2. We conclude that PG synthesis contributes to the basal tone and the hypoxia-induced relaxation of BCA. In addition, hypoxia, unless severe, does not prevent the conversion of AA to PGI2.
呈现自发张力的牛冠状动脉条（BCA）会因浴液中pO2的降低而松弛。进行实验以确定前列腺素（PGs）是否介导了氧诱导的张力变化。将BCA在37℃的Krebs-碳酸氢盐溶液中平衡，用95%O2、5%CO2进行气体置换，并等长测量张力。当浴液介质的pO2降低时，BCA的张力出现可逆性降低。从95%O2、5%CO2转换为95%N2、5%CO2（缺氧）会引发初始松弛，随后是收缩。相反，转换为5%O2、5%CO2、90%N2（低氧）后会出现持续松弛。向缺氧条带重新引入O2会产生双相反应：先是松弛，然后是收缩。吲哚美辛或二十碳四烯酸（EYA）会增加张力，并抑制缺氧或低氧产生的松弛。吲哚美辛或EYA在重新引入O2期间不会抑制缺氧条带的松弛，但会部分抑制收缩。动脉条带对花生四烯酸（AA）的松弛与对前列环素（PGI2）的松弛相似。缺氧会限制对AA的松弛，但不会限制对PGI2的松弛。我们得出结论，PG合成有助于BCA的基础张力和低氧诱导的松弛。此外，除非严重，低氧不会阻止AA转化为PGI2。
