Differential effects of oxycodone, hydrocodone, and morphine on the responses of D2/D3 dopamine receptors

Differential Effects of Oxycodone, Hydrocodone, and Morphine on Activation Levels of Signaling Molecules

“…These differential modulations of signaling are suggested to account for the distinct effects of various opioids on the signaling responses, as well as the locomotor response of D2DRs [7]. The general risks associated with opioid use and abuse have long been understood, and various opioids carry differing levels of efficacy and abuse potential.…”

“…Additionally, oxycodone and morphine have been demonstrated to differentially activate MOR and have differential pain relieving efficacies in various conditions [36]. Moreover, various opioids can have very different levels of side effects, despite equal potency to relieve pain [7,37]. Thus, the differential effects of the various opioids on activation levels of downstream signaling molecules might be attributed to differential effects at the various opioid receptors as well as the differential effects of various opioids on activation of GPCS and bArr-dependent signaling at the same receptor.…”

“…For permissions, please e-mail: journals.permissions@oup.com therapeutic doses [6]. Moreover, mice pretreated with oxycodone showed significantly greater locomotor supersensitivity to quinpirole than did mice pretreated with equianalgesic doses of morphine, while mice pretreated with equianalgesic doses of hydrocodone showed sensitivity between that of mice treated with morphine and oxycodone [7].…”

“…For morphine, these doses roughly correspond to 15 mg/kg base. These doses were selected to represent equianalgesic doses as was confirmed by tail withdrawal test in our previous study [7]. Please note that there are species-and agedependent differences in the pharmacokinetics of opioids (absorbance, metabolism, etc.…”

“…Additionally, we examined the differential effects of repeated administration of oxycodone, hydrocodone, and morphine on altering the signaling responses to quinpirole, a D2/D3 dopamine receptor agonist. We used equianalgesic oral doses of oxycodone, hydrocodone, and morphine that were previously established to provide equianalgesia [7]. As in our previous studies, the oral route was chosen to provide a more accurate and realistic translational model of human administration of oxycodone and hydrocodone and abuse of these prescription opioid medications.…”