Recovery of substance P and related C-terminal fragments on solid-phase extraction cartridges for subsequent high-performance liquid chromatographic separation and radioimmunoassay

Measurement of bioactive neuropeptides using a chromatographic immunosensor cartridge

Neuropeptide modulation of host defenses is associated with a number of clinical conditions in which tissue injury is caused by a process termed neurogenic inflammation. Monitoring of neuropeptide activity during both disease episodes and therapy has proven difficult due to a lack of correlation between laboratory evaluations and disease activity. Although a number of assays are available for measuring the total neuropeptide content of tissue samples, few can measure the bioactive component which is the more physiologically accurate parameter. In an attempt to overcome this problem, a receptor-affinity chromatographic technique coupled with immunological detection has been developed for measuring three bioactive neuropeptides (substance P, vasoactive intestinal peptide, and calcitonin gene-related peptide) in tissue biopsy extracts. The technique involves isolation of the active neuropeptides via their ability to bind to immobilized receptors followed by measurement of the bound materials by a series of simultaneous immunoassays. The techniques compares favourably with results obtained using conventional bioassays and has the added advantage that multiple analytes can be measured in a single procedure.

Sample preparation, high-performance liquid chromatographic separation and determination of substance P-related peptides

This review deals with the determination of low levels of substance P and peptide fragments derived from the undecapeptide, i.e. covers the whole amount of so-called substance P-like immunoreactivity (SPLI) in biological samples. First an overview of the most currently used sample pretreatment procedures is given, followed by a description of the most effective high-performance liquid chromatographic (HPLC) separation methods. Special attention is paid to the choice of the appropriate column and the possible pitfalls encountered in separation of fmol amounts of peptide material. Subsequently the most important techniques of detection are discussed. This section primarily focuses on the coupling of HPLC with radioimmunoassay (RIA), which is indispensable for detection of components in the fmol range at present. Finally, some aspects of preparation and chromatographic separation of radiolabelled antigens for use in RIA are discussed.