Ostádal B, Pelouch V, Ostádalová I, Nováková O
Institute of Physiology, Academy of Sciences of the Czech Republic, Prague.
Mol Cell Biochem. 1995;147(1-2):83-8. doi: 10.1007/BF00944787.
Excessive release or administration of beta-mimetic catecholamines may induce cardiomegaly, necrotic lesions and accumulation of connective tissue in the heart of adult homoiotherms. It was examined here whether similar changes can also be observed at different stages of evolution of the cardiovascular system, i.e. in poikilotherms and in homoiotherms during embryonic life. Sensitivity of the poikilothermic hearts (carp, frog, turtle) to isoproterenol (IPRO) was significantly lower than in the homoiotherms. Necrotic lesions, if present, were localized in the inner spongious musculature which has no vascular supply but which exhibits higher activities of enzymes connected with aerobic oxidation. Moreover, the IPRO-induced decrease of the phospholipid content was also significantly more expressed in the spongious layer. IPRO treatment did not influence the total weight of the fish heart but the proportion of the outer compact layer was significantly higher. These changes were accompanied by an increase of collagen, higher water content and an increase of isomyosin with a lower ATPase activity. The response of the poikilothermic heart to IPRO-induced overload thus differs significantly from that in the homoiotherms. The administration of IPRO during embryonic life of homoiotherms (chick) induces serious cardiovascular disturbances, including cardiomegaly and cellular oedema. Necroses of myofibrils, characteristic of IPRO-induced lesions of adults, were, however, rather exceptional. IPRO did not elevate the concentration of 85Sr (as a calcium homologue) in the immature myocardium; it seems, therefore, that IPRO-induced changes of the embryonic heart are not necessarily due to an intracellular calcium overload. It may be concluded that the character of catecholamine-induced cardiomyopathy is not uniform and depends strictly on the stage of cardiac development.
β - 拟交感儿茶酚胺的过度释放或给药可能会导致成年恒温动物心脏出现心脏肥大、坏死性病变以及结缔组织堆积。本文研究了在心血管系统进化的不同阶段，即变温动物以及恒温动物胚胎期，是否也能观察到类似变化。变温动物（鲤鱼、青蛙、乌龟）的心脏对异丙肾上腺素（IPRO）的敏感性显著低于恒温动物。若出现坏死性病变，则位于内部海绵状肌肉组织，该组织无血管供应，但与有氧氧化相关的酶活性较高。此外，IPRO诱导的磷脂含量降低在海绵层中也更为明显。IPRO处理并未影响鱼心脏的总重量，但外层致密层的比例显著更高。这些变化伴随着胶原蛋白增加、含水量升高以及具有较低ATP酶活性的异肌球蛋白增加。因此，变温动物心脏对IPRO诱导的负荷反应与恒温动物显著不同。在恒温动物（鸡）胚胎期给予IPRO会引发严重的心血管紊乱，包括心脏肥大和细胞水肿。然而，IPRO诱导的成体病变所特有的肌原纤维坏死相当少见。IPRO并未提高未成熟心肌中85Sr（作为钙的同系物）的浓度；因此，似乎IPRO诱导的胚胎心脏变化不一定是由于细胞内钙超载所致。可以得出结论，儿茶酚胺诱导的心肌病特征并不一致，且严格取决于心脏发育阶段。
