Objective: To determine the of effect Arachidonyl-2′-chloroethylamide (ACEA) on the gene expression of renin angiotensin system (RAS) components in rat astrocytes.
Background: We have previously shown that activation of the Angiotensin type 1 receptor (AT1R) altered the expression of the cannabinoid receptor type 1 (CB1R) in rat astrocytes. Activation of the CB1R can potentially have synergistic or antagonistic effects on AT1R actions. Studies have shown that an overactive RAS contributes to pathological conditions. Thus, we determined the molecular effects of activation of the CB1R by ACEA on RAS components. To investigate this, we determined ACEA and Angiotensin (Ang) II effects alone, then combined, on the mRNA levels of RAS components in astrocytes isolated from the cerebellum of Wistar and Spontaneously hypertensive rats (SHRs). CB1R and RAS components are expressed in the cerebellum.
Methods: Astrocytes were prepared from 2-3 days rat pups. Quiescent cells were treated with 10nM ACEA and or 100nM Ang II for 12-24 hours. mRNA levels of RAS components were measured by quantitative polymerase chain reaction.
Results: Ang II predominantly downregulated RAS components in both Wistar and SHR astrocytes at the time points examined. ACEA downregulated AT1R mRNA in Wistar, increased angiotensinogen mRNA in both Wistar and SHR astrocytes, and increased angiotensin converting enzyme mRNA in SHR astrocytes. The effects of combined treatments were similar to Ang II single treatments.
Conclusion: CB1R activation altered the mRNA levels of RAS components but did not appear to have considerable impact on Ang II’s effects on these components. Since mRNA levels might not correlate with protein levels, determination of protein levels and/or activity would complement these findings.
Health Professions Division Grant, Nova Southeastern University
