SUMMARY During a national investigation concerning all patients with Huntington's chorea in South Africa, 17 affected children, comprising 7 7% of the patients in the survey, were identified. Although the frequency of juvenile Huntington's chorea in the white community was equal to that reported from around the world, the frequency was much higher in the population of mixed ancestry. It is possible that this unique situation is related to the genetic constitution of this latter group.

Previous research has shown that fibroblast growth factor 2 protein (FGF2) can act as an anxiolytic and anti-depressive agent in rodents. Levels of hippocampal FGF2 and FGF2 receptors are decreased in post-mortem brains of individuals with mood disorders. No changes in FGF2 were noted in the post-mortem brains of individuals with mood disorders that were successfully treated with anti-depressant medication prior to death. Mutations in the FGF2 gene in humans have been shown to predict non-responsiveness to the therapeutic effects of selective serotonin reuptake inhibitors (SSRIs). These findings suggest that FGF2 may potentially be a target of and/or required for the therapeutic effects of antidepressant medications. To test this, we employed a rodent model of depressive behaviour, chronic variable stress (CVS) in conjunction with antidepressant treatment (fluoxetine) in wild-type (WT) and FGF2 knockout mice (FGF2KO) and examined depressive and anxiety behaviors. Results showed that fluoxetine reversed the effects of CVS on depressive and anxiety behaviours in wild-type mice only, suggesting that the FGF2 gene is indeed necessary for the therapeutic effects of fluoxetine. Interestingly, CVS decreased hippocampal FGF2 levels and fluoxetine partially reversed this effect. Because FGF2 has been previously shown to modify HPA activity through hippocampal glucocorticoid receptors (GR), we examined levels of glucocorticoid receptors and found a decrease in GR in response to CVS, with a further decrease in FGF2KO. No effect of fluoxetine on GR was observed in either WT or FGF2KO mice. This suggests that further changes in glucocorticoid receptors are not necessary for the anti-depressant effects of fluoxetine in WT mice, although decreased glucocorticoid receptors in response to FGF2 deletion may preclude the therapeutic actions of fluoxetine in FGF2KO. Whether astroglia, astroglial functions, or HPA changes are the downstream target of FGF2-mediated changes induced by fluoxetine remains to be determined, however, the current study reaffirms the potential of FGF2 as a novel therapeutic target in the treatment of depression and anxiety disorders.

gene in humans have been shown to predict non-responsiveness to antidepressant drugs; suggesting that FGF2 is required for antidepressants to work. In this study, we hypothesized that antidepressants will not work in rodents that lack the FGF2 gene. Hence, we tested antidepressant treatment in transgenic mice that had the FGF2 gene knocked out. Chronic unpredictable stress (CUS) has been used for several decades to produce a reliable depressive and anxious phenotype in mice. This study followed a CUS paradigm and used fluoxetine (Prozac) as antidepressant treatment. Mice received daily fluoxetine administration beginning on week three of CUS and continued until the end of week five to provide an antidepressant effect and reverse the effects of stress. To test for levels of anxiety and depression, a battery of behavioral tests was conducted which began from the least stressful (i.e. sucrose preference test, open field maze, elevated plus maze) to the most stressful test (forced swim test) to prevent testing carry-over effects. AnyMaze software was used to measure behavior in the open field and elevated plus mazes by recording the amount of time each mouse spent in certain parts of the maze. Future studies will examine brain changes associated with FGF2 gene deletion – particularly in astrocyte cells – which might be necessary for successful antidepressant action. Hopefully, this will elucidate novel therapeutic targets for antidepressant and anti-anxiety medication.

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