Publication Date


Document Type


Committee Members

David Ladle (Committee Member), Debra Mayes (Committee Member), Christopher Wyatt (Advisor)

Degree Name

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.

Page Count


Department or Program

Department of Neuroscience, Cell Biology & Physiology

Year Degree Awarded


Included in

Anatomy Commons