David Ladle (Committee Member), Debra Mayes (Committee Member), Christopher Wyatt (Advisor)
Master of Science (MS)
It is known that opioids inhibit the hypoxic ventilatory response, but little is known about the mechanisms that underpin this. This study's objectives were to examine which opioid receptors are located on the oxygen-sensing carotid body type I cells and determine whether selective agonists inhibit cellular excitability.
Immunocytochemistry revealed the presence of μ and κ opioid receptors on type I cells. The μ-selective agonist DAMGO (10μM) and the κ-selective agonist U50-488 (10μM) significantly (p<0.0025 and p<0.0095 respectively, unpaired student's t-test) inhibited high K+ induced rises in intracellular Ca2+ compared with controls. After a three-hour incubation with pertussis toxin, a Gi protein-coupled inhibitor, DAMGO and U50-488 (10μM) has no significant effect on the responses to K+.
These results indicate that opioids acting at μ and κ receptors inhibit voltage-gated Ca2+ influx in carotid body type I cells. This mechanism may explain, in part, why opioids inhibit the hypoxic ventilatory response.
Department or Program
Department of Neuroscience, Cell Biology & Physiology
Year Degree Awarded
Copyright 2015, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.