Melania Medina
Research Mentor(s): Emily Jutkiewicz
Research Mentor School/College/Department: Pharmacology Department
Presentation Date: 08/03/2022
Presentation Type: Poster
Poster Number: 21
Session: Session I: 12:30 – 1:20pm
Room: League Ballroom
Authors: Melania Medina, Emily Jutkiewicz, PhD
Abstract
With chronic pain becoming increasingly more prevalent, it is estimated that more than 1 in 5
adults suffer from some form of chronic pain in the US. Chronic pain can impact daily activities
such as walking, stair climbing, and work related tasks. Similarly, rodents who experience pain
also show decreases in normal physical activity, more specifically wheel running. The goal of
this project is to evaluate whether or not analgesics can restore pain-suppressed behaviors in
mice. We hypothesize that the mu-opioid receptor agonist will reverse pain-induced suppression
of wheel running behavior in C57BL6/N male mice. After single housing each mouse into
individual cages, mice are given access to a running wheel. A computer then records the number
of wheel revolutions per 15 minute intervals over the 12 hr dark cycle. Once mice demonstrate
consistent patterns of running on the wheel overnight, morphine with or without a noxious
stimulus (0.6% acetic acid) is administered, and changes in wheel revolutions are recorded. Our
preliminary data show that an injection of acetic acid will suppress wheel running behavior in
mice. When comparing pre and post injection data, the mouse receiving acetic acid did not run at
all after an hour following the injection and only ran an average of 341 wheel revolutions
overnight. The mice who received an injection of acetic acid and morphine also did not run after
an hour of injection, however the number of wheel revolutions does increase throughout the
night to an average of 5,500 wheel revolutions. On the contrary, the mice who received an
injection of morphine without the presence of a painful stimulus produced the highest number of
wheel revolutions in an hour after injection (17,000) and averaged out to 14,000 wheel
revolutions overnight. According to our findings, it can be concluded that mice injected with
acetic acid alone significantly inhibit their ability to run, resulting in a decrease in wheel
revolutions. Although morphine did not completely block this effect, data does show that it
suppressed acetic acid induced pain, which further proves that analgesics can restore wheel
running behavior in mice.
