Effect of two behavioral tests on corticosterone level in plasma of mice lacking the noradrenaline transporter.

In the present study, we investigated plasma corticosterone levels of genetically modified mice lacking noradrenaline transporter (NET(-/-)), in response to the forced swim test (FST) and tail suspension test (TST). FST strongly increased the plasma corticosterone level in the first minute after the test (significantly only in NET(+/+) mice), while TST was without any significant effect in both genotypes studied. A single dose of tianeptine (20 mg/kg, ip) shortened immobility time in both tests in NET(-/-) mice, as well as NET(+/+) mice subjected to FST, but not TST. The lack of effect of tianeptine in control animals (NET(+/+)) subjected to TST is also reflected in unchanged levels of plasma corticosterone.