Nano UHPLC-MS/MS optimizations for the in vivo monitoring of possible anticonvulsant neuromedin-like peptides in microdialysates

Abstract

Neuropeptides are an important class of signaling molecules present in the nervous system. Renowned researchers selected neuropeptides as one of the research priorities for future drug development for neurological diseases, including epilepsy, because of their potent, modulatory effect on the extracellular environment and their preferential release in pathological conditions. To obtain better insights in the peptidergic effects involved in epilepsy, it is essential to monitor the concentration dynamics of neuropeptides in the brain. Therefore, the major part of the work was devoted to the development of a selective & sensitive nano ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometric (nano UHPLC-ESI-MS/MS) method for the quantification of three neuromedin-like peptides in microdialysates, i.e. neurotensin, neuromedin B and neuromedin N. Developing bioanalytical methods for peptides is challenging because of their low extracellular concentrations, their low microdialysis efficiencies and their tendency to stick to several surfaces (aspecific adsorption). To achieve the ultimate level of method sensitivity, we focused on the reduction of aspecific adsorption of peptides as well as on the thorough optimization of all the parameters influencing the analysis. The validated assay was subsequently applied for the simultaneous quantification of the three peptides in in vivo microdialysis samples, collected in physiological conditions as well as in response to acute seizures. Additionally, some preliminary pharmacological experiments were performed to identify innovative neuropeptide systems involved in epilepsy.

Date of Award	4 May 2015
Original language	English
Awarding Institution	Vrije Universiteit Brussel
Supervisor	Ilse Smolders (Promotor), Ann Van Eeckhaut (Promotor), Yvette Michotte (Promotor), Debby Mangelings (Jury), Vicky Caveliers (Jury), Ann Massie (Jury), J. Kehr (Jury) & Filip Cuyckens (Jury)