Effects of melatonin on the nitric oxide system and protein nitration in the hypobaric hypoxic rat hippocampus.

BACKGROUND: It is well documented that the nitric oxide (NO) might be directly involved in brain response to hypobaric hypoxia, and could contribute to memory deficiencies. Recent studies have shown that melatonin could attenuate hypoxia or ischemia-induced nerve injuries by decreasing the production of free radicals. The present study, using immunohistochemical and immunoblot methods, aimed to explore whether melatonin treatment may affect the expression of nitric oxide system and protein nitration, and provide neuroprotection in the rat hippocampus injured by hypobaric hypoxia. Prior to hypoxic treatment, adult rats were pretreated with melatonin (100 mg/kg, i.p.) before they were exposed to the altitude chamber with 48 Torr of the partial oxygen concentration (pO2) for 7 h to mimic the ambience of being at 9000 m in height. They were then sacrificed after 0 h, 1, and 3 days of reoxygenation. RESULTS: The results obtained from the immunohistochemical and immunoblotting analyses showed that the expressions of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), nitrotyrosine (Ntyr) and Caspase 3 in the hypoxic hippocampus were increased from 0 h to 3 days of reoxygenation. Interestingly, the hypoxia-induced increase of nNOS, eNOS, iNOS, Ntyr and Caspase 3 protein expression was significantly depressed in the hypoxic rats treated with melatonin. CONCLUSIONS: Activation of the nitric oxide system and protein nitration constitutes a hippocampal response to hypobaric hypoxia and administration of melatonin could provide new therapeutic avenues to prevent and/or treat the symptoms produced by hypobaric hypoxia.

CD200 in growing rat lungs: developmental expression and control by dexamethasone.

CD200 belongs to cell adhesion molecules of the immunoglobulin superfamily. It lacks intracellular signaling motifs and exerts immunosuppressive effect in various tissues. We have reported previously that CD200 is predominantly associated with the capillary network in the alveolar septum of adult rats. The alveolar endothelial cells express CD200, which is confined to their luminal cell membrane facing the blood-air barrier. Our present results show that lung CD200 protein increases gradually with advancing age, being maximally expressed in the early postnatal (P) period. CD200 protein expression, however, declines at P5 but increases again after P7, reaching the adult level at P21. In developing lungs in fetal and neonatal stages, double-immunofluorescence staining has confirmed intense CD200 immunoreactivity delineating the vascular profiles in the double layers of the alveolar capillaries; this staining becomes diffuse and patchy with time. Unlike in adult lungs, immunoelectron microscopy has revealed that CD200 expression in fetal and early postnatal lungs is localized over the entire luminal cell membrane and in the cytoplasm of the endothelia. CD200 expression is progressively redistributed to a specific luminal domain of alveolar endothelia during pulmonary microvascular maturation. In neonatal rats treated with dexamethasone, the amount of lung CD200 significantly increases and is also elevated with time. Upregulation of endothelial CD200 has further been confirmed in isolated pulmonary microvascular endothelial cells treated with dexamethasone. Thus, lung CD200 is developmentally regulated, possibly under hormonal influence.

Hyperbaric oxygen upregulates cochlear constitutive nitric oxide synthase.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) is a known adjuvant for treating ischemia-related inner ear diseases. Controversies still exist in the role of HBOT in cochlear diseases. Few studies to date have investigated the cellular changes that occur in inner ears after HBOT. Nitric oxide, which is synthesized by nitric oxide synthase (NOS), is an important signaling molecule in cochlear physiology and pathology. Here we investigated the effects of hyperbaric oxygen on eardrum morphology, cochlear function and expression of NOS isoforms in cochlear substructures after repetitive HBOT in guinea pigs. RESULTS: Minor changes in the eardrum were observed after repetitive HBOT, which did not result in a significant hearing threshold shift by tone burst auditory brainstem responses. A differential effect of HBOT on the expression of NOS isoforms was identified. Upregulation of constitutive NOS (nNOS and eNOS) was found in the substructures of the cochlea after HBOT, but inducible NOS was not found in normal or HBOT animals, as shown by immunohistochemistry. There was no obvious DNA fragmentation present in this HBOT animal model. CONCLUSIONS: The present evidence indicates that the customary HBOT protocol may increase constitutive NOS expression but such upregulation did not cause cell death in the treated cochlea. The cochlear morphology and auditory function are consequently not changed through the protocol.

Distribution and expression of CD200 in the rat respiratory system under normal and endotoxin-induced pathological conditions.

In vivo and in vitro studies have clearly demonstrated that signaling mediated by the interaction of CD200 and its cognate receptor, CD200R, results in an attenuation of inflammatory or autoimmune responses through multiple mechanisms. The present results have shown a differential expression of CD200 in the respiratory tract of intact rats. Along the respiratory passage, CD200 was specifically distributed at the bronchiolar epithelia with intense CD200 immunoreactivity localized at the apical surface of some ciliated epithelial cells; only a limited expression was detected on the Clara cells extending into the alveolar duct. In the alveolar septum, double immunofluorescence showed intense CD200 immunolabeling on the capillary endothelia. A moderate CD200 labeling was observed on the alveolar type II epithelial cells. It was, however, absent in the alveolar type I epithelial cells and the alveolar macrophages. Immunoelectron microscopic study has revealed a specific distribution of CD200 on the luminal front of the thin portion of alveolar endothelia. During endotoxemia, the injured lungs showed a dose- and time-dependent decline of CD200 expression accompanied by a vigorous infiltration of immune cells, some of them expressing ionized calcium binding adapter protein 1 or CD200. Ultrastructural examination further showed that the marked reduction of CD200 expression was mainly attributable to the loss of alveolar endothelial CD200. It is therefore suggested that CD200 expressed by different lung cells may play diverse roles in immune homeostasis of normal lung, in particular, the molecules on alveolar endothelia that may control regular recruitment of immune cells via CD200-CD200R interaction. Additionally, it may contribute to intense infiltration of immune cells following the loss or inefficiency of CD200 under pathological conditions.

Effects of dietary arginine on inflammatory mediator and receptor of advanced glycation endproducts (RAGE) expression in rats with streptozotocin-induced type 2 diabetes.

Arginine (Arg) is known to possess numerous useful physiological properties and have immunomodulatory effects. In vitro studies reported that Arg inhibits advanced glycation endproduct (AGE) formation; however, the effects of Arg on the receptor of AGE (RAGE) expression in inflammatory conditions are not clear. The present study investigated the effects of dietary Arg supplementation on inflammatory mediator production and RAGE expression in type 2 diabetic rats. There were one normal control (NC) group and two diabetic groups in the present study. Rats in the NC group were fed with a regular chow diet. One diabetic group (DM) was fed a common semi-purified diet while the other diabetic group received a diet in which part of the casein was replaced by Arg (DM-Arg) for 8 weeks. Diabetes was induced by an intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 1800 mg/l were considered diabetic. Blood samples and the liver and lungs of the animals were collected at the end of the study for further analysis. Results showed that plasma glucose and fructosamine contents were significantly higher in the diabetic groups than those in the NC group. The DM group had higher fructosamine and C-reactive protein than the DM-Arg group. Immunohistochemical staining showed that the expressions of RAGE in liver and lung tissues were significantly lower in the DM-Arg group than in the DM group. These results suggest that supplemental dietary Arg can decrease AGE-RAGE interactions and consequently reduce tissue damage in rats with type 2 diabetes.

Motility and protein phosphorylation in healthy and asthenozoospermic sperm.

The majority of male infertility results from poor sperm motility. A direct link between altered protein phosphorylation and aberrant sperm motility has not been established. To address this issue, sperm samples obtained from 20 donors with healthy sperm and 20 donors with aberrantly motile sperm were subjected to computer assisted semen analysis (CASA), proteomic analysis, Western blot, and immunofluorescent staining. Proteomic analysis identified 12 protein spots as having differential phosphorylation, including gamma-tubulin complex associated protein 2 (GCP2). Western blot and immunofluorescence demonstrated differential expression of gamma-tubulin between healthy and aberrantly motile sperm. In conclusion, hypophosphorylated proteins and reduced expression of gamma-tubulin may be associated with low motility sperm.

Endothelial CD200 is heterogeneously distributed, regulated and involved in immune cell-endothelium interactions.

CD200 is a highly glycosylated cell surface protein containing two immunoglobulin superfamily domains in the extracellular region and performs immunosuppressive activities. It is widely distributed in various tissues including the vascular endothelium. We report here the distribution of CD200 in rat endothelia from different vascular beds. Endothelial CD200 immunoreactivity was weakly expressed in most arteries but was intensely expressed in the arterioles, most veins and venules, as well as continuous and fenestrated capillaries. The distribution of CD200 in the sinusoidal and lymphatic endothelia was variable. Immunoelectron microscopic studies revealed that endothelial CD200 varied considerably not only in different microvasculatures but also in the membrane domains at the subcellular level. Endothelial CD200 expression was differentially regulated by lipopolysaccharide in cell types both in vivo and in vitro. Functional assessments of endothelial CD200 suggested that the physical binding between CD200 and CD200 receptor (CD200R) was involved in T-cell adhesion to the endothelium but not in macrophage-endothelium interaction. In the latter, however, CD200 agonist, a synthetic peptide from complementarity-determining region 3 of mouse CD200, may trigger CD200R signaling in macrophages to suppress their adhesion to the endothelium. Our findings demonstrate that the distribution, subcellular localization, and lipopolysaccharide-regulation of endothelial CD200 are heterogeneous, and provide evidence elucidating the functional roles of endothelial CD200 during tissue inflammation.

Methamphetamine induces heme oxygenase-1 expression in cortical neurons and glia to prevent its toxicity.

The impairment of cognitive and motor functions in humans and animals caused by methamphetamine (METH) administration underscores the importance of METH toxicity in cortical neurons. The heme oxygenase-1 (HO-1) exerts a cytoprotective effect against various neuronal injures; however, it remains unclear whether HO-1 is involved in METH-induced toxicity. We used primary cortical neuron/glia cocultures to explore the role of HO-1 in METH-induced toxicity. Exposure of cultured cells to various concentrations of METH (0.1, 0.5, 1, 3, 5, and 10 mM) led to cytotoxicity in a concentration-dependent manner. A METH concentration of 5 mM, which caused 50% of neuronal death and glial activation, was chosen for subsequent experiments. RT-PCR and Western blot analysis revealed that METH significantly induced HO-1 mRNA and protein expression, both preceded cell death. Double and triple immunofluorescence staining further identified HO-1-positive cells as activated astrocytes, microglia, and viable neurons, but not dying neurons. Inhibition of the p38 mitogen-activated protein kinase pathway significantly blocked HO-1 induction by METH and aggravated METH neurotoxicity. Inhibition of HO activity using tin protoporphyrine IX significantly reduced HO activity and exacerbated METH neurotoxicity. However, prior induction of HO-1 using cobalt protoporphyrine IX partially protected neurons from METH toxicity. Taken together, our results suggest that induction of HO-1 by METH via the p38 signaling pathway may be protective, albeit insufficient to completely protect cortical neurons from METH toxicity.

Expression of protein gene product 9.5, tyrosine hydroxylase and serotonin in the pineal gland of rats with streptozotocin-induced diabetes.

Hyperglycemia is a well-known factor in reducing nocturnal pineal melatonin production. However, the mechanism underlying diabetes-induced insufficiency of pineal melatonin has remained uncertain. This study was undertaken to examine the structure, innervation and functional activity of the pineal gland in streptozotocin (STZ)-induced diabetes in rats by immunohistochemistry, Western blotting and image analysis. The number of the pinealocytes and the volume of pineal were also estimated using stereologic quantification including the optical fractionator and Cavalieri's method. It has also shown a progressive reduction of the total area of the pineal gland and the nuclear size of pinealocytes beginning at 4 weeks of induced diabetes. Surprisingly, the immunoreactive intensities and protein amounts of serotonin (5-HT) and protein gene product (PGP) 9.5 in the pineal gland were progressively increased from 4 weeks of diabetes. Meanwhile, nerve fibers immunoreactive for PGP 9.5 had disappeared. Diabetes-induced neuropathy was observed in nerve fibers containing tyrosine hydroxylase (TH). The affected nerve fibers appeared swollen and smooth in outline but they showed a distribution pattern, packing density and protein levels comparable to those of the age-matched control animals. Ultrastructural observations have revealed diabetes-induced deformity of Schwann cells and basal lamina, accumulation of synaptic vesicles and deprivation of the dense-core vesicles in the axon terminals and varicosities. The increase in immunoreactivities in 5-HT and PGP 9.5 and shrinkage of pineal gland in the diabetic rats suggest an inefficient enzyme activity of the pinealocytes. This coupled with the occurrence of anomalous TH nerve fibers, may lead to an ineffective sympathetic innervation of the pinealocytes resulting in reduced melatonin production in STZ-induced diabetes.

Acute Amino Acid d-Serine Administration, Similar to Ketamine, Produces Antidepressant-like Effects through Identical Mechanisms.

d-Serine is an amino acid and can work as an agonist at the glycine sites of N-methyl-d-aspartate receptor (NMDAR). Interestingly, both types of glutamatergic modulators, NMDAR enhancers and blockers, can improve depression through common targets, namely alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionaic acid receptors (AMPARs) and mammalian target of rapamycin (mTOR). To elucidate the cellular signaling pathway underlying this counterintuitive observation, we activated NMDARs in rats by using d-serine. Saline, ketamine (NMDAR antagonist), and desipramine (tricyclic antidepressant) were used as controls. The antidepressant-like effects of all agents were evaluated using the forced swim test. The activation of the AMPAR-mTOR signaling pathway, release of brain-derived neurotrophic factor (BDNF), and alteration of AMPAR and NMDAR trafficking in the hippocampus of rats were examined. A single high dose of d-serine exerted an antidepressant-like effect that was mediated by rapid AMPAR-induced mTOR signaling pathway and increased BDNF proteins, identical to that of ketamine. Furthermore, in addition to the increased protein kinase A phosphorylation of the AMPAR subunit GluR1 (an indicator of AMPAR insertion in neurons), treatment with individual optimal doses of d-serine and ketamine also increased adaptin ß2-NMDAR association (an indicator of the intracellular endocytic machinery and subsequent internalization of NMDARs). Desipramine did not influence these processes. Our study is the first to demonstrate an association between d-serine and ketamine; following adaptative regulation of AMPAR and NMDAR may lead to common changes of them. These findings provide novel targets for safer antidepressant agents with mechanisms similar to those of ketamine.

Antidepressant-like effects of long-term sarcosine treatment in rats with or without chronic unpredictable stress.

Sarcosine, an N-methyl-d-aspartate receptor enhancer, can improve depression-like behavior in rodent models and depression in humans. We found that a single dose of sarcosine exerted antidepressant-like effects with rapid concomitant increases in the mammalian target of rapamycin (mTOR) signaling pathway activation and enhancement of α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR) membrane insertion. Sarcosine may play a crucial role in developing novel therapy for depression. For a detailed understanding of sarcosine, this study examined the effects of long-term sarcosine treatment on the forced swim test (FST), mTOR signaling, and AMPAR membrane insertion in rats. The effects of long-term sarcosine treatment were examined in naive rats and rats exposed to chronic unpredictable stress (CUS). Long-term sarcosine treatment (560mg/kg/d for 21 d) significantly ameliorated the increased immobility induced by CUS in the FST, reaffirming the potential role of sarcosine as an antidepressant for depressed patients. The same long-term treatment exhibited no such effect in naive rats despite increased mTOR activation and AMPAR membrane insertion in both groups. Our findings clearly show CUS-exposed rats are sensitive to long-term sarcosine treatment in FST and the response at the same dose is absent in naïve rats. Nevertheless, the distinct sensitivity to long-term sarcosine treatment in rats with or without CUS is not associated with the activated mTOR signaling pathway or increased AMPAR membrane insertion. Additionally, understanding the behavioral and molecular basis of distinct responses is vital important for developing personalized treatment programs to increase the probability of success when treating depression.

Microglia/macrophages responses to kainate-induced injury in the rat retina.

The present study was aimed to elucidate how retinal microglia/macrophages would respond to neuronal death after intravitreal kainate injection. An increased expression of the complement receptor type 3 (CR3) and an induction of the major histocompatibility complex (MHC) class II and ED-1 antigens were mainly observed in the inner retina after kainate injection. Prominent cell death revealed by Fluoro Jade B (FJB) staining and ultrastructural examination appeared at the inner border of the inner nuclear layer (INL) at 1 day post-injection. Interestingly, some immunoreactive cells appeared at the outer segment of photoreceptor layer (OSPRL) at different time intervals. Our quantitative analysis further showed that CR3 immunoreactivity was drastically increased peaking at 7 days but subsided thereafter. MHC class II and ED-1 immunoreactivities showed a moderate but steady increase peaking at 3 days and declined thereafter. Double labeling study further revealed that retinal microglia/macrophages expressed concurrently CR3 and ED-1 antigens (OX-42+/ED-1+) or MHC class II molecules (OX-42+/OX-6+) and remained branched in shape at early stage of kainate challenge. By electron microscopy, microglia/macrophages with CR3 immunoreactivity displayed abundant cytoplasm containing a few vesicles and phagosomes. Other cells ultrastructurally similar to Müller cells or astrocytes could also engulf exogenous substances. In conclusion, retinal microglia/macrophages responded vigorously to kainate-induced neuronal cell death that may also trigger the recruitment of macrophages from neighboring tissues and induce the phagocytotic activity of cells other than retinal microglia/macrophages.

AMPA Receptor-mTOR Activation is Required for the Antidepressant-Like Effects of Sarcosine during the Forced Swim Test in Rats: Insertion of AMPA Receptor may Play a Role.

Sarcosine, an endogenous amino acid, is a competitive inhibitor of the type I glycine transporter and an N-methyl-d-aspartate receptor (NMDAR) coagonist. Recently, we found that sarcosine, an NMDAR enhancer, can improve depression-related behaviors in rodents and humans. This result differs from previous studies, which have reported antidepressant effects of NMDAR antagonists. The mechanisms underlying the therapeutic response of sarcosine remain unknown. This study examines the role of mammalian target of rapamycin (mTOR) signaling and α-amino-3-hydroxy-5-methylisoxazole-4-propionate receptor (AMPAR) activation, which are involved in the antidepressant-like effects of several glutamatergic system modulators. The effects of sarcosine in a forced swim test (FST) and the expression levels of phosphorylated mTOR signaling proteins were examined in the absence or presence of mTOR and AMPAR inhibitors. In addition, the influence of sarcosine on AMPAR trafficking was determined by analyzing the phosphorylation of AMPAR subunit GluR1 at the PKA site (often considered an indicator for GluR1 membrane insertion in neurons). A single injection of sarcosine exhibited antidepressant-like effects in rats in the FST and rapidly activated the mTOR signaling pathway, which were significantly blocked by mTOR inhibitor rapamycin or the AMPAR inhibitor 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (NBQX) pretreatment. Moreover, NBQX pretreatment eliminated the ability of sarcosine to stimulate the phosphorylated mTOR signaling proteins. Furthermore, GluR1 phosphorylation at its PKA site was significantly increased after an acute in vivo sarcosine treatment. The results demonstrated that sarcosine exerts antidepressant-like effects by enhancing AMPAR-mTOR signaling pathway activity and facilitating AMPAR membrane insertion. Highlights-A single injection of sarcosine rapidly exerted antidepressant-like effects with a concomitant increase in the activation of the mammalian target of rapamycin mTOR signaling pathway.-The antidepressant-like effects of sarcosine occur through the activated AMPAR-mTOR signaling pathway.-Sarcosine could enhance AMPAR membrane insertion via an AMPAR throughput.

Subcellular distributions of calcitonin gene-related peptide (CGRP)-like immunoreactivity in the subcommissural organ of the golden hamster (Mesocricetus auratus).

Immuno-electron microscopy specifically enhanced with silver staining has been used to demonstrate the localization of calcitonin gene-related peptide (CGRP) in the ependymocytes of the hamster subcommissural organ (SCO). Hamster SCO consists of the ependymal and hypendymal cell layers, the latter being arranged as rosette-like structure across the posterior commissure (PC) and often arranged with longitudinal axis parallel to the ventricle. All cytoplasmic regions of the ependymal and hypendymal cells were strongly stained with CGRP. In the hypendymal layer, the CGRP positive hypendymal cells were frequently in contact with local blood vessels and arranged in-groups traversing the thick portion of the PC. Ultrastructurally, the CGRP-immunoreaction products were distributed at the dilated cisternae of the rough endoplasmic reticulum (rER) and secretory granules of the ependymal and hypendymal cells. The dilated cisterna of the rER was usually concentrated in the basal region of the ependymal cells and irregular in shape. These dilated cisternae were filled with a flocculent material or finely granular substance, but hardly studded with ribosomes. Labelled secretory granules were abundant in the apical pole of the ependymal cells and discharged their contents into the third ventricle in the form of a thin layer of secretion. This CGRP positive material appeared to constitute the pre-Reissner's fiber (RF). On the basis of the present ultrastructural evidences, we proposed that ependymocytic CGRP in SCO may be synthesized and stored in the cisternae of rER, then released and incorporated into the RF in the third ventricle through the secretory granules. The abundant amount of CGRP in ependymocytes of SCO and RF in the third ventricle suggests a significant endocrine function of CGRP in hamster SCO.

Microglial distribution and apoptosis in fetal rat brain.

By histochemical and immunocytochemical techniques, this study aimed to determine the possible involvement of apoptosis in regulating the microglial distribution in fetal rat brain. While microglial cells were labeled with the isolectin Griffonia simplicifolia (GSA I-B4), apoptotic cells were detected by using terminal transferase-mediated dUTP nick end-labeling (TUNEL). TUNEL-labeled cells occurred mainly in the dorsal midline along its rostral-caudal axis of the brain where lectin-labeled microglia were also observed. Occasional TUNEL-labeled cells were observed in the intermediate zone lateral to the striatum (IZS) where lectin-labeled microglia were common from embryonic day 16 (E16) onwards. Some of lectin-labeled microglia showing different morphological forms ingested TUNEL-labeled bodies. In contrast, lectin-labeled microglia showing signs of apoptosis appeared to be lacking. These results clearly demonstrated that lectin-labeled microglia were distributed in areas with and without the occurrence of a large concentration of TUNEL-labeled cells. Our studies suggest that microglia in fetal rat brain will undergo differentiation and activation rather than apoptotic death to govern their population.

Comparison of the binding character of triflavin on resting and activated alpha(IIb)beta(3) integrin in human platelets by electron microscopy.

Triflavin, an Arg-Gly-Asp (RGD)-containing disintegrin purified from venom peptide inhibited platelet aggregation by interfering with the interaction of fibrinogen with alpha(IIb)beta(3) integrin. Using an immunostaining technique and electron microscopy, we investigated and compared the distribution of triflavin binding in both resting and activated platelets. Triflavin uniformly and strongly stained the plasma membrane and the open canalicular system (OCS), whereas a lesser extent of staining was seen on alpha-granules in both resting and activated platelets. Furthermore, resting unfixed platelets were incubated with triflavin for 10 min at 4 degrees C, and then rewarmed at 30 degrees C for 0, 10, and 30 min to advance internalization. At 0 min, platelets showed an extensive rim-staining pattern of bound triflavin on the surface membrane, which was then gradually internalized into the cytoplasmic OCS with prolonging of incubation times. However, triflavin bound fewer to alpha-granules than to the OCS within the 0-30-min period of internalization in both resting and activated platelets. Furthermore, triflavin did not influence physiological endocytosis in resting platelets. Comparing the 3D structures of triflavin and another disintegrin, echistatin, we found that the spatial differences between the RGD motif and the C-termini of structures of disintegrins may mediate functional differences of binding activity towards alpha(IIb)beta(3) integrin in resting platelets. These data indicate that (1) triflavin binds effectively to alpha(IIb)beta(3) on the platelet membrane and cytoplasmic OCS, but a relative lesser extent to alpha-granules in both resting and activated platelets; (2) triflavin is internalized in resting platelets independent of cellular activation; and (3) spatial differences between the RGD motif and the C-termini of disintegrins may play an important role in mediating disintegrin binding to alpha(IIb)beta(3) in resting platelets.

Noncontact erection is enhanced by Ginkgo biloba treatment in rats: role of neuronal NOS in the paraventricular nucleus and sacral spinal cord.

RATIONALE: Nitric oxide (NO) is an important messenger mediating erection in the central nervous system (CNS). Paraventricular nucleus (PVN) neurons can be activated by NO and project the signals to the sacral spinal cord, which is involved in regulation of erection. Ginkgo biloba extract (EGb 761) facilitates noncontact erection (NCE) in rats; however, it is not clear whether EGb 761 increased NCE is associated with NO. OBJECTIVE: The present study was designed to investigate the effects of neuronal nitric oxide synthase (nNOS) on NCE in rats following EGb 761 treatment. METHODS: Adult Long-Evans male rats were treated with 50 mg/kg of EGb 761 or distilled water for 14 days. The NCE test was performed after 14 days of EGb 761 treatment and the NCE frequency was recorded. Approximately 14 h following the NCE behavioral tests, animals were sacrificed, and nNOS activity in the PVN and S6-L1 spinal cord was measured by immunohistochemistry and western blotting, respectively. RESULTS: Treatment with 50 mg/kg of EGb 761 for 14 days increased the NCE numbers compared to either the controls treated with distilled water on the same day or the same group on day 0. Also, EGb 761 treatment enhanced nNOS-immunoreactive cell numbers in the PVN. Furthermore, western blot analysis showed that EGb 761-treated animals displayed higher levels of nNOS expression in the S1 spinal cord than controls. CONCLUSION: Our results suggest that enhanced NCE in male rats administrated with EGb 761 may be related to the central nNOS activity in the PVN and the spinal cord.

Ginkgo biloba treatment increases copulation but not nNOS activity in the medial preoptic area in male rats.

Nitric oxide (NO) is an important messenger in the central nervous system to mediate male copulatory behavior. EGb 761, a standardized extract of Gingko biloba, has been reported to facilitate male copulation in rats. The present study is to determine the effects of neuronal nitric oxide synthase (nNOS) in the medial preoptic area (MPOA) on copulation in male rats following EGb 761 treatment. Adult male rats were treated with 50mg/kg of EGb 761 or distilled water by oral gavage for 14 consecutive days. The animals were sacrificed approximately 14h after the last behavioral test and MPOA brain tissues were collected for nNOS immunohistochemistry. EGb 761 treatment for 14 days significantly increased the intromission frequency compared to the vehicle-treated controls on day 14. An increase in ejaculation frequency was also seen in the EGb 761-treated group compared to the vehicle-treated controls on day 14 and to the same group on day 0. However, EGb 761 treatment did not influence the number of nNOS-immunoreactive cells in the MPOA. These results suggest that enhanced male copulatory performance in sexually experienced rats administered EGb 761 may not be related to central nNOS activity in the MPOA.

Resveratrol enhances the expression of death receptor Fas/CD95 and induces differentiation and apoptosis in anaplastic large-cell lymphoma cells.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a phytoalexin found in grapes and other plants, plays a protective role in human atherosclerosis and carcinogenesis. We examined the effects of resveratrol on the anaplastic large-cell lymphoma (ALCL) cell line SR-786. Resveratrol inhibited growth and induced cellular differentiation, as demonstrated by morphological changes and elevated expression of T cell differentiation markers CD2, CD3, and CD8. Resveratrol also triggered cellular apoptosis, as demonstrated by morphological observations, DNA fragmentation, and cell cycle analyses. Further, the surface expression of the death receptor Fas/CD95 was increased by resveratrol treatment. Our data suggest that resveratrol may have potential therapeutic value for ALCL.

Low temperature results in decreased tension in decellularized human nasal mucosa.

BACKGROUND: Cooling may induce nasal obstruction. In our previous study, we showed low temperature induced a rapid relaxation of isolated human nasal mucosa and it was independent of vasoconstriction. The aim of this study was to elucidate the mechanism responsible for such findings. METHODS: Nasal mucosa strips were prepared from inferior turbinate samples. Decellularization of human nasal mucosa was achieved by treatment with sodium dodecyl sulfate 0.1% for 15 hours at 37 degrees C in a shaking water bath. Then, the effect of cooling (37-10 degrees C) on the isometric tension change of decellularized nasal mucosa was evaluated. In addition, the presence of elastic fibers within the nasal mucosa was identified in both histological section and scanning electron microscope. RESULTS: Results indicated cooling induced a relaxation response of isolated decellularized human nasal mucosa and it was similar to that of intact nasal mucosa. The elastic fibers formed in wavy lines and were distributed throughout the submucosal layer. CONCLUSION: Cooling induced a similar relaxation response both in the absence or in the presence of cellular components in isolated human nasal mucosa, suggesting that this response is mediated by the abundant extracellular matrix.