Microdialysis data
Cipralex - Higher serotonin level
The effects of antidepressant drugs on extracellular serotonin levels can be studied pre-clinically by a technique called microdialysis.
This technique allows measurement of serotonin levels in very specific brain areas. A so-called dialysis probe is placed in the area of interest. The dialysis probe is a tiny tube formed as a loop, perfused at a constant velocity with a physiological buffer solution. The tip of the loop is semi-permeable allowing serotonin to diffuse from the extracellular area of the brain into the perfusion media and be transported via the probe to be collected in small samples in tubes. The content of serotonin in these samples can subsequently be determined and presented as microdialysis data.
5-HT in dailysate (% of baseline) (ref.1) Significantly different from escitalopram, p<0.05 |
Effects of Cipralex on the extracellular serotonin level
Microdialysis studies of the frontal cortex have consistently shown that escitalopram is more efficacious than citalopram at increasing extracellular 5-HT levels in the brain. These results are novel and unexpected as, following basic pharmacological profiling, R-citalopram was assumed to be inactive. However, in the light of these new findings, it has been hypothesized that R-citalopram produces an attenuating effect on the escitalopram response. The early onset of action seen with escitalopram in both clinical and pre-clinical studies may be caused by the induction of 5-HT levels that are higher than those induced by citalopram.
Available from CINP 2002 and Mørk paper (ref.1)
References:
1. Adaped from Mørk et. al., 2003