Changes in autoantibodies against beta1-adrenoceptor and M2-muscarinic receptor during development of renovascular hypertension in rats.

In an experimental rat's renovascular hypertension model, we studied the genesis of anti-cardiac beta1-adrenoceptor and M2-muscarinic receptor autoantibodies in relation to the changes in immunological function during the development of renal hypertension. The biological activities of these autoantibodies were also examined. It was shown that after two weeks of operation both the frequency of occurrence and the titre of autoantibodies to cardiac beta1-adrenoceptor and M2-muscarinic receptor were significantly increased as compared with the control of pre-treatment. The increased autoantibodies lasted for several weeks and then automatically decreased gradually to the pre-clipping level at 10 weeks. Meanwhile the ratio of CD4+/CD8+ was also undergone an initial increase followed by gradual recovery and correlated well with the changes in antibody titre. The biological effects of these autoantibodies displayed an "gonistic-like" activities on the beating frequency of cultured neonatal cardiomyocyte. It is suggested that autoimmune mechanisms are involved in the pathogenesis of renal hypertension and the cardiac receptor autoantibodies might be one of the mechanisms leading to cardiac dysfunction.