FAQs
1. Is the BBB the same in all parts of the brain?
No. Different regions of the brain have variations in BBB permeability. For example, areas involved in sensing hormones—such as the hypothalamus—have a slightly leaky BBB to allow communication with the bloodstream. This regional heterogeneity is an area of active research.
2. Can stress or emotions affect the BBB?
Yes. Stress hormones like cortisol can impact BBB permeability. Chronic stress has been linked to weakening of the barrier, which may contribute to higher risks of mood and neurodegenerative disorders.
3. If the BBB blocks most drugs, how do common medicines like painkillers or antidepressants work?
Some small and lipophilic drugs, such as certain antidepressants, caffeine, and nicotine, can diffuse across the barrier. Others are carefully designed to use transport systems already present in the BBB. This is why not all drugs are equally effective for brain conditions—many simply can’t get through.
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