The heptadecapeptide orphanin FQ (OFQ) is a recently discovered neuropeptide that exhibits structural features reminiscent of the opioid peptides and that is an endogenous ligand to a G protein-coupled receptor sequentially related to the opioid receptors. We have cloned both the human and rat cDNAs encoding the OFQ precursor proteins, to investigate whether the sequence relationships existing ...

the role of opioid receptor and voltage dependent calcium channels on the kindling induced by the convulsant pentylenetetrazole (ptz) were investigated in the rats. experiment involved 24 rats which were divided into four groups. kindling was established with ptz in subconvulsive dose (37.5 mg/kg i.p.) every 48 h and effects were observed within 20 min using five-point scoring system. all anima...

introduction: oxytocin is a active neuropeptide of central nervous system. in this study the effects of naloxone (opioid receptor antagonist) and yohimbine (α-2 adrenergic receptor antagonist) on analgesic effect of oxytocin applied into the locus coeruleus (lc) nucleus were investigated. methods: adult male wistar rats were used. animals divided into different groups receiving saline, oxytocin...

The Opioid Growth Regulatory System consists of opioid growth factor (OGF), [Met5]-enkephalin, and its unique receptor (OGFr). OGF inhibits cell division when bound to OGFr. Conversely, blockade of the interaction of OGF and OGFr, using the potent, long-acting opioid receptor antagonist, naltrexone (NTX), results in increased DNA synthesis and cell division. The authors have demonstrated both i...

objectives: crocin, a constituent of saffron and yellow gardenia, possesses anti-nociceptive effects. in the present study, we investigated the effects of intra-fourth ventricle injection of crocin in a rat model of orofacial pain. the contribution of opioid system was assessed using intra-fourth ventricle injection of naloxone, an opioid receptor antagonist. materials and methods: a guide cann...

Ethanol (EtOH) alters neural activity through interaction with various neurotransmitters and neuromodulators. The endogenous opioid system seems to play a key role in the activities of EtOH, since the opioid antagonist naltrexone (ReVia) attenuates craving. We have investigated the transcriptional regulation of opioid system genes in response to EtOH exposure for up to 96 h in human neuroblasto...

Social mammals engage in affiliative interactions both when seeking relief from negative affect and when searching for pleasure and joy. These two motivational states are both modulated by μ-opioid transmission. The μ-opioid receptor (MOR) system in the brain mediates pain relief and reward behaviors, and is implicated in social reward processing and affiliative bonding across mammalian species...

Identification of adaptations to chronic morphine that are causally associated with opioid tolerance formation has long been intensely pursued by the opioid research community. There is an impressive array of components of signaling pathways that are influenced by chronic opioid administration. This underscores the importance to tolerance mechanisms of the complex interplay of cellular adaptati...

The purpose of this study was to evaluate the effects of the gonadal hormones on the opioid receptor protein levels of Freund's adjuvant-treated (arthritic) male and female Lewis rats. Following a paw pressure nociception assay, the midbrain and spinal cord tissues were collected for comparison of mu, delta, and kappa opioid receptor protein levels. The effects of Freund's adjuvant-induced hype...

BACKGROUND The misuse and abuse of opioid medications in many developed nations is a health crisis, leading to increased health-system utilization, emergency department visits, and overdose deaths. There are also increasing concerns about opioid abuse and diversion in patients with cancer, even at the end of life. AIMS To evaluate the current literature on opioid misuse and abuse, and more sp...