ABSTRACT
<p><b>AIM</b>To explore the effects of interleukin-1beta (IL-1beta) on inducible nitric oxide synthase (iNOS)-nitric oxide (NO) system activity in arginine vasopressin (AVP)-induced rat cardiac fibroblasts (CFs).</p><p><b>METHODS</b>CFs were isolated by trypsin digestion method. Nitric acid reductase method, spectrophotometry and reverse transcription-polymerase chain reaction (RT-PCR) were used to detect NO contents, NOS activity and iNOS mRNA expression.</p><p><b>RESULTS</b>AVP significantly increased iNOS mRNA expressions, NOS activity and NO contents (P < 0.05) in CFs. IL-1beta enhanced the effects of AVP on iNOS-NO system activity in a concentration-dependent manner, moreover the iNOS mRNA expressions, NOS activity and NO contents of AVP + 3 ng/ml, AVP + 5 ng/ml IL-1beta group were both significantly higher than those of AVP group (P < 0.05). But when IL-1beta concentration increased to 5 ng/ml, the iNOS mRNA expressions, NOS activity and NO contents did not increase accordingly, slightly decreased instead.</p><p><b>CONCLUSION</b>Within certain range of concentrations IL-1beta cooperates with AVP to increase iNOS-NO system activity in CFs.</p>