Kainic acid down-regulates NOP receptor density and gene expression in human neuroblastoma SH-SY5Y cells.

Nociceptin (N/OFQ) is involved in neuronal excitability and in certain types of seizures. Kainate-induced seizures are associated with increased N/OFQ release in the rat thalamus and hippocampus, causing down-regulation of the N/OFQ receptor (NOP). In this study, we used the neuroblastoma SH-SY5Y cell line as a model to investigate the effects of kainate on NOP receptor density and gene expression.

Nociceptin levels in the cerebrospinal fluid of chronic pain patients with or without intrathecal administration of morphine.

The neuropeptide nociceptin/orphanin FQ (N/OFQ) is the endogenous ligand for the opioid-like receptor ORL-1 and is thought to be involved in pain transmission and modulation. Human studies have not yet defined its role in pain patients. The aims of this study were 1) to verify the presence of N/OFQ in the cerebrospinal fluid (CSF) of human controls and patients with chronic noncancer pain, including those treated with intrathecally administered morphine, and 2) to determine whether pain or treatment with long-term intrathecal morphine influences its levels.

Kainate seizures increase nociceptin/orphanin FQ release in the rat hippocampus and thalamus: a microdialysis study.

The neuropeptide nociceptin/orphanin FQ (N/OFQ) has been suggested to play a facilitatory role in kainate seizure expression. Furthermore, mRNA levels for the N/OFQ precursor are increased following kainate seizures, while its receptor (NOP) density is decreased. These data suggest increased N/OFQ release.

Involvement of the neuropeptide nociceptin/orphanin FQ in kainate seizures.

The neuropeptide nociceptin/orphanin FQ (N/OFQ) has been shown to modulate neuronal excitability and neurotransmitter release. Previous studies indicate that the mRNA levels for the N/OFQ precursor (proN/OFQ) are increased after seizures. However, it is unclear whether N/OFQ plays a role in seizure expression.

Modulation of proorphaninFQ/N gene expression by morphine in the rat mesocorticolimbic system.

We studied the effects of acute and chronic morphine treatment on proorphaninFQ/N (proOFQ/N) gene expression in the mesocorticolimbic system, known to be a reward-relevant area, of the rat CNS. Northern blot analysis revealed that a single injection of morphine 10 mg/kg i.p.