Ingestion of placenta and amniotic fluid has been shown to enhance opioid-mediated analgesia in rats produced by morphine injection, footshock, vaginal/cervical stimulation, and during late pregnancy. The present study was designed to investigate the effects of amniotic fluid ingestion on the characteristics of morphine dependency and withdrawal. Tail-flick latencies in Long-Evans rats were det...

Sustained-release oral morphine sulphate (MST) 20 mg was administered to 11 healthy volunteers. Mean peak plasma morphine concentration was 14.8 ng ml-1, and occurred at a mean time of 142.5 min after ingestion. Analgesia assessed by an ischaemic forearm pain test increased to a maximum approximately 40 min after the calculated peak plasma concentration of morphine had been achieved, and remain...

BACKGROUND Morphine and its derivatives are key drugs in pain control. Despite its well-known analgesic properties morphine at high concentrations may be proalgesic. Particularly, short-lasting painful sensations have been reported upon dermal application of morphine. To study a possible involvement of TRP receptors in the pro-nociceptive effects of morphine (0.3 - 10 mM), two models of nocicep...

in the present study the effects of both cck receptor agonists and antagonists on antinociception induced by morphine in the tail-flick test have been evaluated. m orphine induced dose-dependent antinociception in mice. the response of morphine was potentiated by sulfated cholecystokinin-8 (cck-8s) but not by unsulfated cholecystokinin-8 (cck-8u). the cck receptor antagonists mk-329 and l-365, ...

The aim of this study was to evaluate the effect of curcumin on morphine tolerance and the corresponding cytokine/chemokine changes. Male ICR mice were made tolerant to morphine by daily subcutaneous injection for 7 days. Intraperitoneal injections of vehicle, low-dose or high-dose curcumin were administered 15 min after morphine injection, either acutely or chronically for 7 days to test the e...

INTRODUCTION Calcium/calmodulin-dependent protein kinase II (CaMKII) which is highly expressed in the hippocampus is known to play a pivotal role in reward-related memories and morphine dependence. METHODS In the present study, repeated morphine injections once daily for 7 days was done to induce morphine tolerance in male Wistar rats, after which gene expression profile of α-isoform of CaMKI...

UNLABELLED Morphine is among the most prevalent analgesics prescribed for chronic pain. However, prolonged morphine treatment results in the development of analgesic tolerance. An abundance of evidence has accumulated indicating that central nervous system glial cell activity facilitates pain transmission and opposes morphine analgesia. While the midbrain ventrolateral periaqueductal gray (vlPA...

This study investigated possible sex-related differences in levels of antinociception and the rate of development of tolerance to the antinociceptive effects following prolonged (48 h) intravenous (i.v.) morphine administration in the rat. Groups of adult intact male, castrated male, female, and testosterone-pretreated female Sprague-Dawley rats received prolonged (48 h) infusions of i.v. morph...

BACKGROUND Codeine analgesia is wholly or mostly due to its metabolism to morphine by the cytochrome P450 enzyme CYP2D6, which shows significant genetic variation in activity. The aims of this study were to investigate genotype, phenotype and morphine production from codeine in children undergoing adenotonsillectomy, and to compare analgesia from codeine or morphine combined with diclofenac. ...

BACKGROUND Learning and memory processes can be affected by morphine administration. It has been previously demonstrated that the effects of morphine depend on the timing of drug administration. In the present study, the effects of microinjections of a NMDA receptor agonist and antagonist into the CA1 regions of the dorsal hippocampi (intra-CA1) on repeated pretreatment of morphine-induced prev...