Subtype-selective GABAA receptor (GABAAR) modulators have been shown to relax pre-contracted human airway smooth muscle and alleviate airway hyperresponsiveness in a murine model of asthma.1, 2 Further lead development resulted in modulators with limited CNS distribution and additional anti-inflammatory effects. The pharmacological effect of these compounds is mediated by different lung cell types including white blood cells that have been shown to express discrete GABAAR subtypes. Pharmacokinetic analysis demonstrated excellent long lasting concentrations of GABAAR modulators in the lung. Herein, we present the spatial lung distribution of GABAAR modulators using imaging mass spectrometry (IMS).3 This new MALDI IMS technique provides spatial and molecular specificity by detecting a unique m/z for the analyte of interest at specific coordinates within the tissue section. In concert with immunohistochemistry, marking the expression of different GABAAR subunits, IMS-microscopy fusion enables visualization of drug-receptor interactions ex vivo. Other IMS-microcopy fusion images will be presented based on H&E and periodic acid fluorescent Schiff’s tissue stains to visualize distribution and localization of GABAAR modulators in the lung. 1-Forkuo, G. S. et al. Mol Pharm 2016, 13, 2026-38. 2-Yocum, G. T. et al. Am J Respir Cell Mol Biol 2016, 54, 546-53. 3-Chumbley, C.W. et al. Anal. Chem. 2016, 88, 2393-2396.

Imaging the distribution of selective GABAA receptor modulators in the asthmatic lung using MALDI assisted mass spectrometry

253rd National Meeting (2017)

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