Minimal effective brain level

Similarly, the minimal effective brain level, MEBL (nmol/g), required for the drug to interfere with the conditioned avoidance response of rats correlates linearly with IPav. The least-squares correlation is... 

Functional activity (clinical effect, catalepsy in animals, etc.) is invariably correlated with plasma concentrations whereas the brain levels of many neuroleptics, which are very lipophilic compounds, could be much higher. Some clinicians also believe that many newer compounds achieve atypical status compared with older ones because they are used at minimal dosage while older ones are prescribed at established levels which may be unnecessarily high. 

Similarly, lithium-7 MRS has been used to examine the pharmacokinetics of lithium, a drug that is widely used in the treatment of a number of psychiatric disorders. Initial studies showed that there was a slow accumulation of lithium in the brain, which may be responsible for the delay in therapeutic response that is often seen following the initiation of therapy. Subsequent studies showed that lithium levels in the brain and muscle were lower than the average serum concentration. From the ratio of these in vivo measurements, the authors hypothesized that the minimal effective concentration of brain lithium level for maintenance treatment... 

Copper is essential for some of the enzymes that have a role in brain metabolism. Sophisticated mechanisms balance copper import and export to ensure proper nutrient levels (homeostasis) while minimizing toxic effects. Several neurodegenerative diseases including AD are characterized by modified copper homeostasis. This change seems to contribute either directly or indirectly to increased oxidative stress, an important factor in neuronal toxicity. The association of misfolded proteins and modified copper homeostasis appears to be important in the pathological progression of AD [Donnelly et al., 2007],... 

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