Rasmussen Natalie Ann, Farr Lynne A
College of Nursing, University of Nebraska Medical Center, 985330 Nebraska Medical Center, Omaha, NE 68198-5330, USA.
J Neurosci Methods. 2009 Mar 15;177(2):285-8. doi: 10.1016/j.jneumeth.2008.10.013. Epub 2008 Oct 21.
The timing of the measurement of biological samples (e.g. biomarkers) is not always standardized. Biomarkers are the focus of many recent studies and treatments. The purpose of this study was to determine the timing of the release of beta-endorphin (BE), a possible biomarker, after exposure to pain and/or handling stress in order to standardize measurements. Mouse plasma was collected for BE analysis following handling i.e. being picked up by the investigator, exposure to a painful (55 degrees C hot-plate), or exposure to a nonpainful stimulus (room temperature hot-plate). The groups exposed to either a painful or nonpainful stimulus released BE in response to the stimulus, but the duration of the response was longer in mice exposed to a painful stimulus than in mice exposed to a nonpainful stimulus. The BE in the mice exposed to a nonpainful stimulus peaked at 1 min and returned to baseline levels by 5 min while the BE response of the mice exposed to a painful stimulus peaked at 10 min and remained elevated for 25 min. The results of this study indicate that BE can be a biomarker for pain and handling stress, however, the timing of the measurement should differ.
