Opioids are the oldest and most potent drugs for the treatment of severe pain. Their clinical
application is undisputed in acute (eg, postoperative) and cancer pain, but their long-term …

The use of opioid analgesics has a long history in clinical settings, although the
comprehensive action of opioid receptors is still less understood. Nonetheless, recent …

The calcium ion (Ca2+) is the simplest and most versatile intracellular messenger known.
The discovery of Ca2+ sparks and a related family of elementary Ca2+ signaling events has …

Intracellular G protein-coupled receptors (GPCRs) can be activated by permeant ligands,
which contributes to agonist selectivity. Opioid receptors (ORs) provide a notable example …

Delta and mu opioid receptors (DORs and MORs) are inhibitory G protein-coupled receptors
that reportedly cooperatively regulate the transmission of pain messages by substance P …

Cellular interactions between delta and mu opioid receptors (DORs and MORs), including
heteromerization, are thought to regulate opioid analgesia. However, the identity of the …

Controversy remains regarding the mechanisms of acupuncture analgesia. A prevailing
theory, largely unproven in humans, is that it involves the activation of endogenous opioid …

The role of peptides as signalling molecules in the nervous system has been studied for
more than 30 years. Neuropeptides and their G-protein-coupled receptors are widely …

This review summarizes recent findings on peripheral mechanisms underlying the
generation and inhibition of pain. The focus is on events occurring in peripheral injured …

Morphine and other opioids are used and abused for their analgesic and rewarding
properties. Tolerance to these effects develops over hours/days to weeks, as can physical …