Elsevier

Analytical Biochemistry

Volume 371, Issue 1, 1 December 2007, Pages 26-36
Analytical Biochemistry

Refinement of a radioreceptor binding assay for nicotinic acid adenine dinucleotide phosphate

https://doi.org/10.1016/j.ab.2007.08.030Get rights and content
Under a Creative Commons license
open access

Abstract

The measurement of changes in nicotinic acid adenine dinucleotide phosphate (NAADP) levels in cells has been, and remains, key to the investigation of the functions of NAADP as a Ca2+-releasing second messenger. Here we provide details of how to isolate NAADP from cells by extraction with perchloric acid and then measure the NAADP using a radioreceptor assay. We demonstrate that NAADP is neither generated nor broken down during sample processing conditions and that radioreceptor assay is highly selective for the detection of NAADP under cell extract conditions. Furthermore, a number of improvements, such as solid-state detection of the radioactivity, are incorporated to enhance the safety of the procedure. Finally, we have developed a new method to prevent the endogenous metabolism of NAADP by chelating Ca2+ with bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), thereby reducing the difficulty of catching a small transient rise in NAADP levels. In summary, we have refined and improved a method for measuring NAADP levels and presented it in a manner accessible to a wide range of laboratories. It is expected that this will enhance research in the NAADP field.

Keywords

NAADP
Mammalian
Second messenger
Radioreceptor

Cited by (0)

1

These authors contributed equally to this work.

2

Current address: Institut de Neurosciences, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès (Barcelona), Catalonia, Spain.

3

Current address: Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.

4

Current address: MRC Laboratory of Molecular Biology, Neurobiology Division, Cambridge CB2 2QH, UK.

5

Current address: ResVerLogix Corporation, Calgary, Alberta T2L 2K7, Canada.