Taki F, Takagi K, Satake T, Sugiyama S, Ozawa T
Am Rev Respir Dis. 1986 Mar;133(3):362-6. doi: 10.1164/arrd.1986.133.3.362.
This investigation was designed to elucidate the role of phospholipase (PLase) in relation to reduced beta-adrenergic responsiveness in guinea pigs subjected to experimental asthma. In the in vivo experiment, guinea pigs that had developed asthma-like symptoms after exposure to an aerosol of 2% ovalbumin for 7 to 8 min for 10 successive days were used as the experimental asthma group. The control group was exposed to saline. The endogenous PLase activity was determined by high performance liquid chromatography using ditridecanoyl phosphatidylcholine as a substrate. PLase activity of lung membranes in the experimental asthma group was significantly elevated by 50% compared with that in the control group. Phospholipid content of lung membranes in the experimental asthma group was decreased by 11% compared with that in the control group. The experimental asthma group showed a 37% decrease in the number of beta-adrenoceptors in lung membranes and a 54% decrease in isoproterenol-stimulated adenylate cyclase activity in lung membranes compared with the control group. Although forskolin-stimulated adenylate cyclase activity was also reduced by 24%, decreases in forskolin-stimulated activity were less than decreases in isoproterenol-stimulated activity. In the in vitro experiment phospholipids in lung membranes were degraded by pretreatment with 0.1 U of PLase A2. After pretreatment of lung membranes with PLase A2, the number of beta-adrenoceptors was reduced by 25% compared with that in the control group, and adenylate cyclase activity stimulated by isoproterenol and forskolin were also reduced by 67 and 28%, respectively. PLase A2 had a minor effect on forskolin-stimulated activity as compared with isoproterenol-stimulated activity.(ABSTRACT TRUNCATED AT 250 WORDS)
本研究旨在阐明磷脂酶（PLase）在实验性哮喘豚鼠β-肾上腺素能反应性降低方面的作用。在体内实验中，连续10天每天暴露于2%卵清蛋白气雾剂7至8分钟后出现哮喘样症状的豚鼠用作实验性哮喘组。对照组暴露于生理盐水。以内源性PLase活性以二月桂酰磷脂酰胆碱为底物，采用高效液相色谱法测定。实验性哮喘组肺膜的PLase活性比对照组显著升高50%。实验性哮喘组肺膜的磷脂含量比对照组降低11%。与对照组相比，实验性哮喘组肺膜中β-肾上腺素能受体数量减少37%，异丙肾上腺素刺激的肺膜腺苷酸环化酶活性降低54%。虽然福司可林刺激的腺苷酸环化酶活性也降低了24%，但福司可林刺激活性的降低小于异丙肾上腺素刺激活性的降低。在体外实验中，用0.1 U的PLase A2预处理可降解肺膜中的磷脂。用PLase A2预处理肺膜后，β-肾上腺素能受体数量比对照组减少25%，异丙肾上腺素和福司可林刺激的腺苷酸环化酶活性也分别降低67%和28%。与异丙肾上腺素刺激的活性相比，PLase A2对福司可林刺激的活性影响较小。（摘要截断于250字）
