Performance of heterozygous brain-derived neurotrophic factor knockout mice on behavioral analogues of anxiety, nociception, and depression

Evidence suggests that brain-derived neurotrophic factor (BDNF) may be impo rtant in the pathophysiology of depression, in addition to its role as a ne urotrophic factor for sensory neurons. The authors conducted a series of ex periments examining the behavioral profile of BDNF heterozygous knockout an d wild-type mice. The heterozygous and wild-type mice did not differ on mea sures of activity, exploration, or hedonic sensitivity, or in the forced sw im test. When assessed in the learned helplessness paradigm, heterozygous m ice were slower to escape after training than were wild-type mice (p = .02) . This effect may be accounted for by the fact that these mice demonstrate a reduced sensitivity to centrally mediated pain, apparent on the hot plate and Formalin injection tests of nociception. Overall, heterozygous mice we re not more likely to display anxious or depressive-like behaviors and, con sequently, may not constitute a murine model of genetic vulnerability to mo od and anxiety disorders.