Date of Award


Document Type

Masters Thesis

Degree Name


Organizational Unit

College of Natual Science and Mathematics, Biological Sciences

First Advisor

Robert M. Dores, Ph.D.


Opium, Chordates, Origins


The interest in the opioid/orphanin gene family stems from functional similarities that these peptides have to the narcotic opium. Opiates have been extensively studied because of their analgesic properties; however, the reason that these plant products can affect the human central nervous system was a mystery until the discovery of opiate-like peptides. The endogenous opioid peptides are well understood today because they have been fully cloned and characterized in several different organisms including lower chordates. On the other hand, the opioid/orphanin receptors have not been fully cloned or characterized in lower chordates; therefore, to better understand the past and present evolutionary path of the opioid/orphanin gene family it is important to have opioid receptor sequence information available over a broad taxonomic scale in lower chordates. This study reveals opioid/orphanin receptor sequence from Petromyzon marinus (lamprey), Heterodontus francisci (horn shark), and Acipenser transmontanus (white sturgeon). This sequence information exposed the conservation of critical amino acids within the opioid binding pocket and disulfide bridge, uncovered the possibility of crucial amino acids involved in ligand selectivity, and offered a proposed hypothesis for the evolutionary relationship between the four opioid/orphanin receptors.

Publication Statement

Copyright is held by the author. User is responsible for all copyright compliance.

Rights Holder

Jazalle DeShaun McClendon


Received from ProQuest

File Format




File Size

101 p.


Molecular Biology