Parenteral opioids for pain relief during labor have been the subject of research for many decades. Commonly used systemic opioids provide limited pain relief during labor yet are used extensively for managing labor pain. These opioids share similar pharmacologic profiles but differ in potency, pharmacokinetics, and side effects. This article reviews the pharmacokinetics, pharmacodynamics, and ...

BACKGROUND The N-methyl-D-aspartate subtype of glutamate receptor plays a critical role in morphine tolerance. D-serine, a co-agonist of N-methyl-D-aspartate receptor, participates in many physiological and pathophysiological processes via regulating N-methyl-D-aspartate receptor activation. The purinergic P2X7 receptor activation can induce the D-serine release in the central nervous system. T...

The present study aimed to compare the effects of oxycodone and morphine hydrochloride on the proliferation, apoptosis and migration of A549 lung cancer cells. A549 human lung cancer cells were cultured in vitro and treated with oxycodone or morphine at various concentrations (10, 20 and 40 µg/ml). Cell migration was determined using a wound healing assay, whereas apoptosis was detected using f...

The concept of ligand bias at G protein-coupled receptors broadens the possibilities for agonist activities and provides the opportunity to develop safer, more selective therapeutics. Morphine pharmacology in β-arrestin-2 knockout mice suggested that a ligand that promotes coupling of the μ-opioid receptor (MOR) to G proteins, but not β-arrestins, would result in higher analgesic efficacy, less...

AIM To determine whether cannabinoids suppress noxious stimulus-evoked Fos protein-like immunoreactivity (FLI) through direct actions at the spinal level. METHODS Rats were implanted with intrathecal (ith) catheters at least one week prior to evaluation in the formalin test. Effects of the cannabinoid agonist, CP55,940 (80 micrograms ith) on formalin pain and FLI in rat spinal cord were compa...

The utility of methadone and morphine for analgesia and of methadone for substitution therapy for heroin addiction is a consequence of these drugs acting as opioid receptor agonists.We compared the cataleptogenic and antinociceptive effects of single subcutaneous doses of methadone hydrochloride (1-4 mg/kg) and morphine sulfate (2.5-10 mg/kg) using catalepsy and hot-plate tests, and examined th...

Topical drugs avoid many of the problematic side effects of systemic agents. Immersion of the tail of a mouse into a solution of dimethyl sulfoxide (DMSO)-containing morphine produces a dose-dependent, naloxone-sensitive, analgesia (ED(50) 6.1 mM; CL 4.3, 8.4) limited to the portion of the tail exposed to the drug. DMSO alone in this paradigm had no analgesic activity. Like morphine, the opioid...

Morphine-6-glucuronide (M6G), an active metabolite of morphine, has been shown to have significantly attenuated brain penetration relative to that of morphine. Recently, we have demonstrated that conjugation of various drugs to peptide vectors significantly enhances their brain uptake. In this study, we have conjugated morphine-6-glucuronide to a peptide vector SynB3 to enhance its brain uptake...

The Gbetagamma subunit has been implicated in many downstream signaling events associated with opioids. We previously demonstrated that a small molecule inhibitor of Gbetagamma-subunit-dependent phospholipase (PLC) activation potentiated morphine-induced analgesia (Bonacci et al., 2006). Here, we demonstrate that this inhibitor, M119 (cyclohexanecarboxylic acid [2-(4,5,6-trihydroxy-3-oxo-3H-xan...

THE recent introduction of a powerful general analgesic drug, phenazocine (" Narphen"), with a potency stated to be seven to ten times that of morphine (Eckenhoff, 1959) has enabled us to make use of its unique properties in ophthalmic surgery. The drug possesses fewer undesirable side-effects on respiration and on the circulation than morphine or pethidine, and does not produce vomiting, an im...