Abe M, Yamazaki N, Suzuki Y, Kobayashi A, Ohta H
J Mol Cell Cardiol. 1984 Mar;16(3):239-45. doi: 10.1016/s0022-2828(84)80590-8.
The accumulation of long chain of acyl carnitine, which is thought to exaggerate myocardial ischemic damage, has been demonstrated in ischemic myocardium. The purpose of this study was to determine the effect of palmitoyl carnitine on the Na+, K+-ATPase and adenylate cyclase activity of myocardial sarcolemma in vitro. Controversial views exist at present regarding the effect of palmitoyl carnitine on Na+, K+-ATPase. Wood et al. [23] observed that palmitoyl carnitine inhibited the activity of Na+, K+-ATPase but this inhibition was not observed by Owens et al. [17]. We did observe an inhibition of Na+, K+-ATPase by palmitoyl carnitine. The 50% inhibition of the maximum activity was observed at a palmitoyl carnitine concentration of 110 microM and complete inhibition at 160 microM. Adenylate cyclase activity was inhibited by palmitoyl carnitine irrespective of the assay conditions. The (isoproterenol + GTP)-stimulated activity, fluoride-stimulated activity and basal activity with Mg-ATP or Mn-ATP as a substrate were all inhibited though to varying degrees. The 50% inhibition of adenylate cyclase activity was observed at 84 microM, 94 microM, 200 microM and 105 microM of palmitoyl carnitine in the above mentioned order. The inhibition curve showed a shoulder or even a peak at about 75 microM of palmitoyl carnitine. It is suggested that elevated levels of palmitoyl carnitine in ischemic myocardium may play a role in inhibiting sarcolemmal function.
长链酰基肉碱的蓄积被认为会加剧心肌缺血损伤，已在缺血心肌中得到证实。本研究的目的是在体外确定棕榈酰肉碱对心肌肌膜钠钾ATP酶和腺苷酸环化酶活性的影响。目前关于棕榈酰肉碱对钠钾ATP酶的影响存在争议性观点。伍德等人[23]观察到棕榈酰肉碱抑制钠钾ATP酶的活性，但欧文斯等人[17]未观察到这种抑制作用。我们确实观察到棕榈酰肉碱对钠钾ATP酶有抑制作用。在棕榈酰肉碱浓度为110微摩尔时观察到最大活性被抑制50%，在160微摩尔时完全抑制。无论检测条件如何，腺苷酸环化酶活性均被棕榈酰肉碱抑制。以异丙肾上腺素+鸟苷三磷酸（GTP）刺激的活性、氟化物刺激的活性以及以镁-三磷酸腺苷（Mg-ATP）或锰-三磷酸腺苷（Mn-ATP）为底物的基础活性均受到不同程度的抑制。上述情况下，在棕榈酰肉碱浓度分别为84微摩尔、94微摩尔、200微摩尔和105微摩尔时观察到腺苷酸环化酶活性被抑制50%。抑制曲线在棕榈酰肉碱浓度约为75微摩尔时出现一个平台甚至一个峰值。提示缺血心肌中升高的棕榈酰肉碱水平可能在抑制肌膜功能中起作用。
