The opioid system modulates complex processes such as neuroendocrine function, analgesia, immunity, and cardiovascular regulation. A challenge in the field of neuroscience has been the molecular characterization of the opioid receptors. The recent isolation and sequencing of the genes and cDNAs encoding the opioid receptors permit studies of structure, function, and the cellular localization of...

background and objective: the effect of opioids on the reproductive system has been studied as an attractive research field. in this study, the effect of morphine as an analgesic opioid was evaluated on the ovarian polycystic induction in the rat. materials & methods: in this study, 24 female virgin wistar rats weighing 200-250 g were injected with morphine (1-10 mg/kg/day) for 9 days. cont...

Increased pain sensitivity after opioid administration (opioid-induced hyperalgesia) and/or repeated painful stimuli is an individually varying and clinically important phenomenon. The functional polymorphism (val(158)met) of the Catechol-O-methyltransferase (COMT) gene regulates the metabolism of dopamine/noradrenaline. Individuals homozygous for the met(158) allele have been reported to have ...

The realization that the mu-opioid system plays a key role in the control of the process of neuroinflammation is a new concept that may lead to identification of novel therapies for this extremely widespread and intractable syndrome. Fever is the hallmark among the defense mechanisms evoked by the entry into the body of pathogens to initiate the innate immune responses. In an attempt to determi...

The discovery of the opioid receptors began in the 1970s and three (μ, δ and κ) are now recognised. Most current opioid analgesics interact preferentially with μ receptors, although some have actions at δ and κ receptors. The revelation that opioid receptors are present on peripheral sensory neurones and immune system cells, has led to the realisation that the opioid system is involved in a hos...

There is increasing evidence supporting a link between the endogenous opioid system and excessive alcohol consumption. Acute or light alcohol consumption stimulates the release of opioid peptides in brain regions that are associated with reward and reinforcement and that mediate, at least in part, the reinforcing effects of ethanol. However, chronic heavy alcohol consumption induces a central o...

Reductions in pain ratings when administered a placebo with expected analgesic properties have been described and hypothesized to be mediated by the pain-suppressive endogenous opioid system. Using molecular imaging techniques, we directly examined the activity of the endogenous opioid system on mu-opioid receptors in humans in sustained pain with and without the administration of a placebo. Si...

1 Molecular Cloning of Opioid Receptors by cDNA Library Screening Ying-Xian Pan ......................................................................................... 3 2 Expression of Opioid Receptors in Mammalian Cell Lines Ying-Xian Pan ....................................................................................... 17 3 Assessing Opioid Regulation of Adenylyl Cyclase Activity in I...

Morphine injected locally to the paw of an adult or an infant rat is analgesic. Opiates specific to micro and kappa opioid receptors, and less consistently to delta opioid receptors, given locally to the site of injury in adult animals are also analgesic in a variety of models of inflammatory pain. To determine which opioid receptor(s) are involved in local analgesia in the immature animal, ago...