Neurochemical research
-
Neurochemical research · Jan 2013
Regulation of ERα protein expression by 17β-estradiol in cultured neurons of hypothalamic ventromedial nucleus.
The activation of the subtype α of estrogen receptors (ERα) in the hypothalamic ventromedial nucleus (VMNvl) is required to stimulate female sexual receptivity. Moreover, the hormone was found to govern the expression of the receptor. Its removal due to ovariectomy and subsequent substitution suggest that the hormone down-regulates the expression of ERα. ⋯ The particular contribution of the receptors is dependent on their level of expression and the hormonal context. In neurons expressing high quantity of ERα, ERβ attenuates the overall expression of the receptor, whereas in cells containing mostly ERβ it contributes to the up-regulation of ERα synthesis. Simultaneous activation of ERs and PRs reverses the influences of the receptors due to inter-inhibition of their transcriptional activities.
-
Neurochemical research · Oct 2012
Pharmacokinetics of glutamate-oxaloacetate transaminase and glutamate-pyruvate transaminase and their blood glutamate-lowering activity in naïve rats.
Traumatic brain injury (TBI) and stroke lead to elevated levels of glutamate in the brain that negatively affect the neurological outcomes in both animals and humans. Intravenous administration of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) enzymes can be used to lower the blood glutamate levels and to improve the neurological outcome following TBI and stroke. The objective of this study was to analyze the pharmacokinetics and to determine the glutamate-lowering effects of GOT and GPT enzymes in naïve rats. ⋯ We conclude that the interaction between the systemically-administered enzymes (GOT and GPT) and the glutamate takes place in the central circulation. Thus, glutamate-lowering effects of GOT and GPT apparently lead to redistribution of the excess glutamate from the brain's extracellular fluid into the blood and can reduce secondary brain injury due to glutamate neurotoxicity. The outcomes of this study regarding the pharmacokinetic and pharmacodynamic properties of the GOT and GPT enzymes will be subsequently verified in clinical studies that can lead to design of effective neuroprotective treatment strategies in patients with traumatic brain diseases and stroke.
-
Neurochemical research · Oct 2012
Postoperative cognitive dysfunction is correlated with urine formaldehyde in elderly noncardiac surgical patients.
Post-operative cognitive dysfunction (POCD), especially in elderly patients, has been reported in many studies. Although increasing age, duration of anesthesia, postoperative infections, and respiratory complications were regarded as the risk factors for POCD, no extracerebral diagnostic biomarkers have been identified as indicators of POCD. Ninety-five patients, ages 65-80 years, scheduled for major orthopedic or abdominal surgery were enrolled. ⋯ Although the changes in urine formaldehyde of young patients during perioperative period were similar to those in elderly patients without POCD, the formaldehyde concentrations measured at four time points were all significantly lower than those in elderly patients (p < 0.05). Levels of urine formaldehyde were elevated in the perioperative period, with the highest levels at day 7 in patients with POCD. This suggests that the increase on day 7 may provide a new physiologic marker along with neuropsychological assessments to assist in the diagnosis of POCD.
-
Neurochemical research · Oct 2012
Geniposide reduces inflammatory responses of oxygen-glucose deprived rat microglial cells via inhibition of the TLR4 signaling pathway.
Geniposide, an iridoid glycoside isolated from Gardenia, has neuroprotective activities against oxidative stress and inflammation. The present study investigated the in vivo protective effect of geniposide on ischemia/reperfusion-injured rats by middle cerebral artery occlusion (MCAO), and the inhibitory effects of geniposide and mechanisms against activation of microglial cells by oxygen-glucose deprivation (OGD) in vitro. Male SD rats were subjected to treatment with geniposide at 15, 30 and 60 mg/kg immediately after MCAO. ⋯ Geniposide also attenuated the increases in the OGD-induced TLR4 mRNA and protein levels. In addition, geniposide at 25 and 50 μg/mL downregulated the phosphorylation of ERK, IκB and p38, as well as inhibited nuclear transcriptional activity triggered via NF-κB p65 in microglial cells by OGD. In conclusion, geniposide displays a neuroprotective effect on ischemia/reperfusion-injured rats in vivo and inhibits OGD-induced activation of microglial cells by attenuating inflammatory factors and NF-κB activation in vitro.
-
Neurochemical research · Sep 2012
Assessment of oxidative parameters in rat spinal cord after chronic constriction of the sciatic nerve.
Although reactive oxygen species (ROS) are involved in neuropathic pain, the direct relationship between these species and chronic constriction of sciatic nerve (CCI) has not been studied in spinal cord. Thus, this study induced CCI in rats and these animals were sacrificed 3 and 10 days after the surgical procedure to determine the superoxide dismutase (SOD) and catalase activities, as well as ascorbic acid, hydrogen peroxide (H(2)O(2)) and lipid hydroperoxide levels in lumbosacral spinal cord. Von Frey Hair and hot plate tests were performed to assess the degree of mechanical and thermal hyperalgesia at days 0, 3 and 10. ⋯ SOD activity was decreased in Sham and CCI groups at day 3, while catalase activity was increased in CCI rats at days 3 and 10. Ascorbic acid levels were reduced only in CCI rats at day 3. Although the role of such changes is unclear, many were not specific to neuropathic pain and the differences could be related to different degrees of central sensitization in Sham and CCI rats.