Date of Award

Fall 11-10-2010

Degree Type


Degree Name

Master of Science (MS)



First Advisor

Anne Z. Murphy

Second Advisor

Matthew Grober

Third Advisor

William Walthall


Chronic pain in the aged is a widespread phenomenon, and morphine is the most commonly used narcotic analgesic for treatment. Despite that fact, there are relatively few published studies examining the impact of advanced age on morphine analgesia. We hypothesized that aged rats would be less sensitive to morphine than adults, and that aged animals would have reduced mu-opioid receptor (MOR) binding and expression in the ventrolateral periaqueductal gray, a brain region responsible for morphine analgesia. Using a model of persistent inflammatory pain, we found that morphine was significantly less effective in aged males compared to adult males, and that aged males and females experience a reduction in MOR binding and expression compared to adults. These results suggest that there are clear age differences in morphine efficacy, and that reductions in MOR binding and expression in the periaqueductal gray could underlie those differences.


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