Capillary LC-MS/MS of drugs and neuropeptides in microdialysis samples in 'in vivo' neuropharmacology research

This project aims to develop a number of analytical assays for the quantitative determination of neuropeptides and drugs in microdialysates using capillary LC coupled to triple quadrupole electrospray MS/MS. Because of the low concentrations expected in the dialysates (pM range) maximal sensitivity of the methods needs to be achieved. Therefore, both microdialysis and LC parameters need to be optimized. The developed methods will be applied in specific projects within the laboratory.
In our PK/PD studies of anti-epileptic drugs, the combination of microdialysis sampling and nano-LC-MS/MS has the advantage that in each dialysate (max 40µL) the concentration of the PD marker as well as the drug under investigation can be determined. The use of LC-MS/MS can save us time (high throughput) en provide us with a lot of interesting information that can be used in more difficult applications.
Indeed, we also want to determine the neuropeptides (somatostatin, dynorphin, galanin …) in microdialysates from the hippocampus in order to study the neuropeptide transmission before, during and after experimentally-induced convulsions. Afterwards, we will investigate whether this peptide release can be modulated with peptidergic ligands, but also ligands of ionotropic and metabotropic glutamate receptors. Similarly, we will study the peptide transmission (enkephalin, dynorphin, substance P…) in animal models of Parkinson’s disease in order to evaluate their role in motor control.
Finally, we are also interested in the in vivo metabolisation of Ang II and its fragments in different brain regions (hippocampus, striatum and cortex). By local continuous perfusion of Ang II via the microdialysis probe we will determine the concentration of these fragments by LC- MS/MS.