Background The intrinsic efficacy of opioid analgesics has been suggested to play a role in
the development of tolerance to these agents. However, the effect of differences in dosing …

The present study examined the contribution of downregulation of μ-opioid receptors to
opioid tolerance in an intact animal model. Mice were implanted subcutaneously with osmotic …

The role of endocrine factors on opioid analgesia (antinociception) and opioid receptors was
studied in male and female Swiss-Webster mice. Morphine was more potent in male than in …

The effect of chronic opioid antagonist treatment on the analgesic potency of six opioid agonists
was compared to changes in opioid receptor density and the selectivity of each agonist …

The effect of chronic treatment with opioid agonists and antag- receptor density, although
tolerance to morphine was observed onists on i opioid receptor density and opiold potency …

Opioid antagonists can be classified as inverse agonists and neutral antagonists. In the
opioid-dependent state, neutral antagonists are significantly less potent in precipitating …

It has been proposed that opioid agonist efficacy may play a role in tolerance and the
regulation of opioid receptor density. To address this issue, the present studies estimated the in …

Studies suggest that acute and chronic opioids can regulate the cAMP‐dependent protein
kinase (PKA) signaling pathway and that changes in this pathway may be involved in opioid …

Chronic opioid agonist treatment produces tolerance and in some cases opioid receptor
internalization and down-regulation. Both morphine and etorphine induce tolerance; however, …

Rats were implanted with an indwelling vascular cannula in the jugular vein, femoral artery
or carotid artery, and evaluated for postsurgical weight changes and cannula patency. …