Neurotrophins and depression

Exogenous delivery of the neurotrophic factors, brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3), promotes the function, sprouting an d regrowth of 5-HT-containing neurones in the brains of adult rats. Similar infusions of BDNF into the dorsal raphe nucleus produce an antidepressant effect, as evaluated by several 'learned helplessness' paradigms. Environme ntal stressors such as immobilization induce depression and decrease BDNF m RNA. Antidepressants increase BDNF mRNA in the brain, via 5-HT2A and beta-a drenoceptor subtypes and prevent the stress-induced decreases in BDNF mRNA. In this article, Tony Altar discusses how existing treatments of depressio n might work by increasing endogenous brain levels of BDNF or NT-3, which i n turn could promote monoamine-containing neurone growth and function. Drug s that selectively stimulate the production of neurotrophins could represen t a new generation of antidepressants.