Role of nociceptin/orphanin FQ and nociceptin opioid peptide receptor in depression and antidepressant effects of nociceptin opioid peptide receptor antagonists

Nociceptin/orphanin FQ (N/OFQ) and its receptor, nociceptin opioid peptide (NOP) receptor, are localized in brain areas implicated in depression including the amygdala, bed nucleus of the stria terminalis, habenula, and monoaminergic nuclei in the brain stem. N/OFQ inhibits neuronal excitability of monoaminergic neurons and monoamine release from their terminals by activation of G protein-coupled inwardly rectifying K⁺ channels and inhibition of voltage sensitive calcium channels, respectively. Therefore, NOP receptor antagonists have been proposed as a potential antidepressant. Indeed, mounting evidence shows that NOP receptor antagonists have antidepressant-like effects in various preclinical animal models of depression, and recent clinical studies again confirmed the idea that blockade of NOP receptor signaling could provide a novel strategy for the treatment of depression. In this review, we describe the pharmacological effects of N/OFQ in relation to depression and explore the possible mechanism of NOP receptor antagonists as potential antidepressants.

Exploring the Mechanism of Baicalin in Influencing Cells Infected with Chlamydia Pneumoniae by Observing Its Effect on Receptors / 广州中医药大学学报

[Objective] To observe the effect of Baicalin on the expression of Toll-like receptors (TLRs) induced by chlamydia pneumoniae (CPN). [Methods] The endothelial cells of umbilical veins (ECV-304) was cultured in-vitro in 6-well culture plate (3 double-wells as a group). When a single layer formed, CPN or CPN + baicalin (0.48 g/L or 0.24 g/L) was added, serving as the model group and baicalin groups respectively. The wells without adding agents served as the normal group. After 5 days of culture, the intracellular growth of CPN in ECV-304 was examined by monoclonal antibody fluorescence labeling method and Giemsa stain, and the expression of TLR2 mRNA and TLR4 mRNA was detected by reverse transcriptase polymerase chain reaction (RT-PCR) in the model group. Protein expression of TLR2 on ECV-304 cell surface in the cultured supernatants was detected with flow cytometer. [Results] The intracellular growth of CPN can be found in ECV-304. The expression of TLR4 mRNA was undetectable, and high expression of TLR2 mRNA and TLR2 protein existed in ECV-304. Baicalin in high doses could lower the expression of TLR2 protein. [Conclusion] Baicalin has an inhibitory effect on the high expression of TLR2 protein in ECV-304 stimulated by CPN.