[Changes in adrenomedullin and receptor activity-modifying protein 2 mRNA in myocardium and vessels during L-NNA-induced hypertension in rats]

To explore the changes in adrenomedullin (ADM) and receptor activity-modifying protein 2 (RAMP2) mRNA in myocardium and vessels in hypertension, a hypertensive rat model was prepared by administering L-NNA. Contents of ADM in plasma, myocardium and vessels were measured by radioimmunoassay (RIA). The levels of pro-ADM mRNA of myocardium and vessels were determined by competitive quantitative RT-PCR. The results showed that L-NNA induced hypertension and cardiomegaly. The ratio of heart to body weight increased by 35.5% (P0.01). In hypertensive rats the ir-ADM in plasma, myocardium and vessels was increased by 80%, 72% and 57% (P0.01), respectively compared with the control. The amounts of ADM mRNA in myocardium and vessels were increased by 50% and 109.2% (P0.05), respectively, and the amounts of RAMP2 mRNA was increased by 132% and 87% (P0.01), respectively, compared with control. The levels of ADM in myocardium and vessels were positively correlated with RAMP2 mRNA, the correlation coefficients were 0.741 and 0.885 (P0.01), respectively. The results obtained indicate that in hypertensive rats, ADM is elevated in plasma, myocardium and ves-myocardium and vessel, and ADM and RAMP2 mRNA are up-regulated in myocardium and vessel. The ADM/RAMP2 system may play an important role in the pathogenesis of hypertension.