Increased blood pressure variability induces depression-like behavior and gap junction protein changes in rats

OBJECTIVE To study depression-like behavior caused by the increase in blood pressure variability and mechanisms involving gap junction protein.METHODS Adult male SD rats were divided into two groups: the sham control and sinoaortic denervation(SAD), which were examined for various behaviors using sucrose preference, forced swimming, and light-dark transition tests 2, 4, 8, and 16 weeks after sham or SAD surgery. The expression levels of CX40, CX43, CX45,and BDNF were detected in tissues from the left front prefrontal cortex and hippocampus using Western blotting. The expression levels of CX43 were also confirmed using RT-PCR. RESULTS Compared with the sham control, the SAD rats showed lower sucrose preference rate, longer immobility time in the forced swimming test, and shorter retention time in the illuminated chamber in the light-dark transition test. The expression of CX40 and CX45 in was increased while the expression of CX43 and BDNF was decreased in SAD rats. RT-PCR revealed decreased CX43 expression in the hippocampus of SAD rats. All the above changes were observed 2-16 weeks after SAD. CONCLUSION Increased blood pressure variability produces depression-and anxiety-like behavior, which is likely mediated by gap junction protein.