Excess of leptin inhibits hypothalamic KiSS-1 expression in pubertal mice.

Purpose: Leptin has been considered a link between metabolic state and reproductive activity. Defective reproductive function can occur in leptin-deficient and leptin-excessive conditions. The aim of this study was to examine the effects of centrally injected leptin on the hypothalamic KiSS-1 system in relation to gonadotropin-releasing hormone (GnRH) action in the initial stage of puberty.

Bark Constituents from Mushroom-detoxified Rhus verniciflua Suppress Kainic Acid-induced Neuronal Cell Death in Mouse Hippocampus.

Urushinol, a plant allergen, has significantly restricted the medical application of Rhus verniciflua, although it has been reported to possess a wide variety of biological activities such as anti-inflammatory, antioxidant, and anti-cancer actions. To reduce the urushinol content while maintaining the beneficial biological activities, mushroom-mediated fermentation of Rhus verniciflua was carried out and this method resulted in significantly attenuated allergenicity [1]. In the present study, to examine the neuroprotective properties of mushroom-fermented stem bark of Rhus verniciflua, two constituents were isolated from mushroom-fermented bark and their neuroprotective properties were examined in a mouse model of kainic acid (KA)-induced excitotoxicity.

Neuroprotective effects of stanniocalcin 2 following kainic acid-induced hippocampal degeneration in ICR mice.

Stanniocalcin 2 (STC2), the paralog of STC1, has been shown to act as a novel target of the mammalian unfolded protein response. We investigated the potential neuroprotective actions of STC2 against kainic acid toxicity in the hippocampus of ICR mice. STC2-treated mice experienced less neuronal cell loss in the CA3 area of the hippocampus.

Inhibition of eNOS/sGC/PKG Pathway Decreases Akt Phosphorylation Induced by Kainic Acid in Mouse Hippocampus.

The serine/threonine kinase Akt has been shown to play a role of multiple cellular signaling pathways and act as a transducer of many functions initiated by growth factor receptors that activate phosphatidylinositol 3-kinase (PI3K). It has been reported that phosphorylated Akt activates eNOS resulting in the production of NO and that NO stimulates soluble guanylate cyclase (sGC), which results in accumulation of cGMP and subsequent activation of the protein kinase G (PKG). It has been also reported that PKG activates PI3K/Akt signaling.

Kainic Acid-induced Neuronal Death is Attenuated by Aminoguanidine but Aggravated by L-NAME in Mouse Hippocampus.

Nitric oxide (NO) has both neuroprotective and neurotoxic effects depending on its concentration and the experimental model. We tested the effects of NG-nitro-L-arginine methyl ester (L-NAME), a nonselective nitric oxide synthase (NOS) inhibitor, and aminoguanidine, a selective inducible NOS (iNOS) inhibitor, on kainic acid (KA)-induced seizures and hippocampal CA3 neuronal death. L-NAME (50 mg/kg, i.

Melatonin Induces Akt Phosphorylation through Melatonin Receptor- and PI3K-Dependent Pathways in Primary Astrocytes.

Melatonin has been reported to protect neurons from a variety of neurotoxicity. However, the underlying mechanism by which melatonin exerts its neuroprotective property has not yet been clearly understood. We previously demonstrated that melatonin protected kainic acid-induced neuronal cell death in mouse hippocampus, accompanied by sustained activation of Akt, a critical mediator of neuronal survival.