精氨酸升压素对烫伤休克大鼠心功能的抑制作用及其机制

^The inhibitory action of arginine vasopressin on cardiac function and its mechanism in burn shocked rats

采用放射免疫测定、心功能记录与离体心肌实验等方法，研究了精氨酸升压素（ＡＶＰ）对烫伤休克大鼠心功能的影响。结果表明：烫伤休克时，垂体向血液释放ＡＶＰ增多，血浆ＡＶＰ水平升高非常显著；ＡＶＰＶ１和Ｖ２受体特异性拮抗剂均可不同程度地改善烫伤休克大鼠的心功能，但后者作用较强；Ｖ１和Ｖ２受体拮抗剂亦能拮抗ＡＶＰ对离体心肌收缩的抑制作用；ＡＶＰ可升高心肌ｃＡＭＰ和ｃＧＭＰ含量，但后者高于前者，使ｃＧＭＰ／ｃＡＭＰ比值增高。提示ＡＶＰ除有缩血管作用外，对心肌还有直接的负性变力作用，参与了烫伤休克大鼠心功能抑制的病理过程，此作用是由心肌上的ＡＶＰ受体介导的，其第二信使可能与ｃＧＭＰ有关。

Radioimmunoassay,cardiac function measurement and in vitro cardiac muscular strip study were employed in this study to investigate the effect of arginine vasopressin (AVP) on cardiac function in the burn shocked rat.Results showed that there was an enhanced release of AVP from the posterior pituitary to the blood resulting in pronounced increase in plasma AVP during burn shock.Both specific AVP V1 and V2 receptor antagonists could improve the cardiac function during burn shock with the latter more effective. V1 and V2 receptor antagonists could also block the inhibitory effect of AVP on the contraction of isolated right atria and right ventricular muscular strip in vitro.AVP stimulated both cAMP and cGMP accumulation in the cardiac muscle,but with the latter predominating resulting in increased cGMP/cAMP ratio.The above results suggest that AVP excerts direct negative inotropic effect on cardiac function in addition to its vasoconstricting effect during burn shock,which is mediated through AVP receptor present in the heart with the possible second messenger cGMP.