Combination of metformin/efavirenz/fluoxetine exhibits profound anticancer activity via a cancer cell-specific ROS amplification

The possible anticancer activity of combination (M + E + F) of metformin (M), efavirenz (E), and fluoxetine (F) was investigated in normal HDF cells and HCT116 human colon cancer cells. Metformin increased cellular FOXO3a, p-FOXO3a, AMPK, p-AMPK, and MnSOD levels in HDFs but not in HCT116 cells. Cellular ATP level was decreased only in HDFs by metformin. Metformin increased ROS level only in HCT116 cells. Transfection of si-FOXO3a into HCT116 reversed the metformin-induced cellular ROS induction, indicating that FOXO3a/MnSOD is the key regulator for cellular ROS level. Viability readout with M, E, and F alone decreased slightly, but the combination of three drugs dramatically decreased cell survival in HCT116, A549, and SK-Hep-1 cancer cells but not in HDF cells. ROS levels in HCT116 cells were massively increased by M + E + F combination, but not in HDF cells. Cell cycle analysis showed that of M + E + F combination caused cell death only in HCT116 cells. The combination of M + E + F reduced synergistically mitochondrial membrane potential and mitochondrial electron transport chain complex I and III activities in HCT116 cells when compared with individual treatments. Western blot analysis indicated that DNA damage, apoptosis, autophagy, and necroptosis-realated factors increased in M + E + F-treated HCT116 cells. Oral administration with M + E + F combination for 3 weeks caused dramatic reductions in tumor volume and weight in HCT116 xenograft model of nude mice when compared with untreated ones. Our results suggest that M + E + F have profound anticancer activity both in vitro and in vivo via a cancer cell-specific ROS amplification (CASRA) through ROS-induced DNA damage, apoptosis, autophagy, and necroptosis.

Purple corn extract alleviates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like phenotypes in BALB/c mice

Zea mays L. (Poaceae), also known as purple corn, is an annual herbaceous plant that is grown as food for human consumption in a variety of forms, including cooking oils and sweeteners in processed food and beverage products. The purpose of this study was to determine whether a novel purple corn extract, FB801, might have an anti-atopic dermatitis (AD) effect on AD-like skin lesions induced by 2,4-dinitrochlorobenzene (DNCB) in BALB/c mice. Topical sensitization (1%) and challenge (0.3%) by DNCB were performed on the dorsal skin and right ear of BALB/c mice to induce AD. Following FB801 and dexamethasone administered orally, the severity of skin lesions was examined macroscopically and histologically. Serum levels of immunoglobulin E (IgE) and various cytokines were determined by enzyme-linked immunosorbent assay. Oral administration of FB801 significantly reduced typical symptoms of AD (erythema/bleeding, swelling, molting/erosion and scaling/drying), scratching frequencies, and the recruitment of inflammatory and mast cells. In addition, FB801 suppressed serum levels of IgE and T helper (Th)2 type cytokines such as interleukin (IL)-4 and IL-10 in DNCB-treated BALB/c mice. Furthermore, FB801 reduced the degradation of inhibitor of nuclear factor-κB proteins (NF-κB) in tumor necrosis factor (TNF)-α-stimulated human keratinocyte (HaCaT) cells. These results suggest that FB801 inhibited the development of the AD-like skin symptoms by regulating Th1 and Th2 responses in the skin lesions in mice and suppressing TNF-α induced NF-κB activation in HaCaT cells, suggesting that FB801 has potential application as an effective alternative therapy for the prevention and management of AD.

Changes in plasma lipoxin A4, resolvins and CD59 levels after ischemic and traumatic brain injuries in rats

Ischemic and traumatic brain injuries are the major acute central nervous system disorders that need to be adequately diagnosed and treated. To find biomarkers for these acute brain injuries, plasma levels of some specialized pro-resolving mediators (SPMs, i.e., lipoxin A4 [LXA4], resolvin [Rv] E1, RvE2, RvD1 and RvD2), CD59 and interleukin (IL)-6 were measured at 0, 6, 24, 72, and 168 h after global cerebral ischemic (GCI) and traumatic brain injuries (TBI) in rats. Plasma LXA4 levels tended to increase at 24 and 72 h after GCI. Plasma RvE1, RvE2, RvD1, and RvD2 levels showed a biphasic response to GCI; a significant decrease at 6 h with a return to the levels of the sham group at 24 h, and again a decrease at 72 h. Plasma CD59 levels increased at 6 and 24 h post-GCI, and returned to basal levels at 72 h post-GCI. For TBI, plasma LXA4 levels tended to decrease, while RvE1, RvE2, RvD1, and RvD2 showed barely significant changes. Plasma IL-6 levels were significantly increased after GCI and TBI, but with different time courses. These results show that plasma LXA4, RvE1, RvE2, RvD1, RvD2, and CD59 levels display differential responses to GCI and TBI, and need to be evaluated for their usefulness as biomarkers.

Adiponectin stimulates glucose uptake in mouse blastocysts and embryonic carcinoma cells

Preimplantation embryos are sensitive to maternal hormones affecting embryonic signal transduction and metabolic functions. We examined whether adiponectin, the most abundantly secreted adipokine, can influence glucose transport in mouse embryonic cells. In mouse blastocysts full-length adiponectin stimulated glucose uptake, while no effect of globular adiponectin was found. Full-length adiponectin stimulated translocation of GLUT8 glucose transporter to the cell membrane; we did not detect significant changes in the intracellular localization of GLUT4 glucose transporter in adiponectin-treated blastocysts. To study adiponectin signaling in detail, we used embryoid bodies formed from mouse embryonic carcinoma cell (ECC) line P19. We confirmed the expression of adiponectin receptors in these cells. Similar to mouse blastocysts, full-length adiponectin, but not globular adiponectin, stimulated glucose uptake in ECC P19 embryoid bodies. Moreover, full-length adiponectin stimulated AMPK and p38 MAPK phosphorylation. These results indicate that besides AMPK, p38 MAPK is a potential target of adiponectin in mouse embryonic cells. AMPK inhibitor did not influence the adiponectin-stimulated p38 MAPK phosphorylation, indicating independent action of these two signaling pathways. In mouse embryos adiponectin acts as a hormonal regulator of glucose uptake, which becomes especially important in phases with reduced levels of circulating insulin. Our results suggest that adiponectin maintains the glucose supply for early embryos under hypoinsulinaemic conditions, for example, in mothers suffering from type 1 diabetes mellitus.

G2A Protects Mice against Sepsis by Modulating Kupffer Cell Activation: Cooperativity with Adenosine Receptor 2b

G2A is a GPCR abundantly expressed in immune cells. G2A^-/- mice showed higher lethality, higher plasma cytokines, and an impaired bacterial clearance in response to a murine model of sepsis (cecal ligation and puncture), which were blocked by GdCl₃, an inhibitor of Kupffer cells. Anti-IL-10 Ab reversed the impaired bacterial clearance in G2A^-/- mice. Indomethacin effectively blocked both the increased i.p. IL-10 levels and the impaired bacterial clearance, indicating that disturbed PG system is the proximal cause of these phenomena. Stimulation with LPS/C5a induced an increase in Escherichia coli phagocytosis and intracellular cAMP levels in G2A^+/+ peritoneal macrophages but not G2A^-/- cells, which showed more PGE₂/nitrite release and intracellular reactive oxygen species levels. Heterologous coexpression of G2A and adenosine receptor type 2b (A2bAR) induced a synergistic increase in cAMP signaling in a ligand-independent manner, with the evidence of physical interaction of G2A with A2bAR. BAY 60-6583, a specific agonist for A2bAR, increased intracellular cAMP levels in Kupffer cells from G2A^+/+ but not from G2A^-/- mice. Both G2A and A2bAR were required for antiseptic action of lysophosphatidylcholine. These results show inappropriate activation of G2A^-/- Kupffer cells to septic insults due to an impaired cAMP signaling possibly by lack of interaction with A2bAR.

Anti-inflammatory effects of traditional mixed extract of medicinal herbs (MEMH) on monosodium urate crystal-induced gouty arthritis

Korean oriental medicine prescription is widely used for the treatment of gouty diseases. In the present study, we investigated anti-inflammatory effects of modified Korean herbal formulation, mixed extract of medicinal herbs (MEMH), and its modulatory effects on inflammatory mediators associated with gouty arthritis. Both in vitro and in vivo studies were carried out to assess the anti-inflammatory efficacy of MEMH on monosodium urate (MSU) crystals-induced gouty inflammation. MSU crystals stimulated human chondrosarcoma cell line, SW1353, and human primary chondrocytes were treated with MEMH in vitro. The expression levels of pro-inflammatory mediators and metalloproteases were analyzed. The effect of MEMH on NFκB signaling pathway in SW1353 cells was examined. Effect of MEMH on the mRNA expression level of pro-inflammatory mediators and chemotactic factor from human monocytic cell line, THP-1, was also analyzed. The probable role of MEMH in the differentiation process of osteoblast like cells, SaOS-2, after MSU treatment was also observed. To investigate the effects of MEMH in vivo, MSU crystals-induced ankle arthritic model was established. Histopathological changes in affected joints and plasma levels of pro-inflammatory mediators (IL-1β and TNFα) were recorded. MEMH inhibited NFκB signaling pathway and COX-2 protein expression in chondrocytes. MSU-induced mRNA expressions of pro-inflammatory mediators and chemotactic cytokines were suppressed by MEMH. In MSU crystals-induced ankle arthritic mouse model, administration of MEMH relieved inflammatory symptoms and decreased the plasma levels of IL-1β and TNFα. The results indicated that MEMH can effectively inhibit the expression of inflammatory mediators in gouty arthritis, demonstrating its potential for treating gouty arthritis.

Characterization of changes of pain behavior and signal transduction system in food-deprived mice

Fasting in general causes several metabolic changes. In the present study, we examined the possible changes of several types of nociception during the food deprivation were investigated in mice. After the mice were forced into the fasting for 12, 24, or 48 h, the changes of nociception were measured by the tail-flick, writhing, formalin or von-frey tests. We found that the nociceptive behavior induced by intraperitoneally (i.p.) administered acetic acid (writhing response) or intraplantar injection of 5% formalin into the hind-paw were reduced in fasted group. In addition, the tail-flick response and threshold for nociception in mechanical von-frey test were also elevated in fasted group. Moreover, the p-CREB and p-ERK levels in the dorsal root ganglia (DRG) and the spinal cord were reduced in food-deprived group. Furthermore, p-AMPKα₁ expressions in DRG and the spinal cord were up-regulated, whereas p-mTOR in DRG and the spinal cord was down-regulated in food-deprived group. Our results suggest that the chemical, mechanical, and thermal nociceptions appear to be reduced in a food-deprived mouse group. Additionally, reduction of nociception in food-deprived group appears to be closely associated with the expressions of several signal transduction molecules such as ERK, CREB, AMPKα₁ and mTOR proteins in DRG and the spinal cord.

Lipidomic analysis of plasma lipids composition changes in septic mice

A lipidomic study on extensive plasma lipids in bacterial peritonitis (cecal ligation and puncture, CLP)-induced sepsis in mice was done at 24 h post-CLP. The effects of administration of lysophosphatidylcholine (LPC) and lysophosphatidic acid (LPA), compounds known to have beneficial effects in CLP, on the sepsis-induced plasma lipid changes were also examined. Among the 147 plasma lipid species from 13 lipid subgroups (fatty acid [FA], LPA, LPC, lysophosphatidylethanolamine [LPE], phosphatidic acid [PA], phosphatidylcholine [PC], phosphatidylethanolamine [PE], phosphatidylinositol [PI], monoacylglyceride [MG], diacylglyceride [DG], triacylglyceride [TG], sphingomyelin [SM], and ceramide [Cer]) analyzed in this study, 40 and 70 species were increased, and decreased, respectively, in the CLP mice. Treatments with LPC and LPA affected 14 species from 7 subgroups, and 25 species from 9 subgroups, respectively. These results could contribute to finding the much needed reliable biomarkers of sepsis.

The activation of α2-adrenergic receptor in the spinal cord lowers sepsis-induced mortality

The effect of clonidine administered intrathecally (i.t.) on the mortality and the blood glucose level induced by sepsis was examined in mice. To produce sepsis, the mixture of D-galactosamine (GaLN; 0.6 g/10 ml)/lipopolysaccharide (LPS; 27 µg/27 µl) was treated intraperitoneally (i.p.). The i.t. pretreatment with clonidine (5 µg/5 µl) increased the blood glucose level and attenuated mortality induced by sepsis in a dose-dependent manner. The i.t. post-treatment with clonidine up to 3 h caused an elevation of the blood glucose level and protected sepsis-induced mortality, whereas clonidine post-treated at 6, 9, or 12 h did not affect. The pre-treatment with oral D-glucose for 30 min prior to i.t. post-treatment (6 h) with clonidine did not rescue sepsis-induced mortality. In addition, i.t. pretreatment with pertussis toxin (PTX) reduced clonidine-induced protection against mortality and clonidine-induced hyperglycemia, suggesting that protective effect against sepsis-induced mortality seems to be mediated via activating PTX-sensitive G-proteins in the spinal cord. Moreover, pretreatment with clonidine attenuated the plasma tumor necrosis factor α (TNF-α) induced by sepsis. Clonidine administered i.t. or i.p. increased p-AMPKα1 and p-AMPKα2, but decreased p-Tyk2 and p-mTOR levels in both control and sepsis groups, suggesting that the up-regulations of p-AMPKα1 and p-AMPKα2, or down-regulations of p-mTOR and p-Tyk2 may play critical roles for the protective effect of clonidine against sepsis-induced mortality.

Spinal β-adrenergic receptors' activation increases the blood glucose level in mice

We examined the role of spinally located β-adrenergic receptors in the regulation of the blood glucose level. The intrathecal (i.t.) injections with dobutamine (β₁-adrenergic receptor agonist) or terbutaline (β₂-adrenergic receptor agonist) caused an elevation of the blood glucose level, whereas metoprolol (β₁-adrenergic receptor antagonist) or butoxamine (β₂-adrenergic receptor antagonist) did not. In addition, i.t. pretreatment with pertussis toxin (PTX) attenuated the hyperglycemic effect induced by dobutamine or terbutaline. Moreover, plasma insulin level was increased by dobutamine but not by terbutaline, and PTX reduced dobutamine-induced up-regulation of the plasma insulin level. Terbutaline significantly increased plasma corticosterone level, and PTX further enhanced terbutaline-induced corticosterone level. Furthermore, intraperitoneal (i.p.) pretreatment with hexamethonium- (a preganglionic blocker) attenuated dobutamine- and terbutaline-induced hyperglycemic effects. Our results suggest that activation of spinal β₁- and β₂-adrenergic receptors produces hyperglycemic effects in a different manner. Spinally located PTX-sensitive G-proteins appear to be involved in hyperglycemic effect induced by terbutaline. Furthermore, dobutamine- or terbutaline-induced hyperglycemia appears to be mediated through the spinal nerves.

Regulation of blood glucose level by kainic acid in mice: involvement of glucocorticoid system and non-NMDA receptors

Kainic acid (KA) is a well-known excitatory neurotoxic substance. In the present study, effects of KA-injected intraperitoneally (i.p.), intracerebroventricularly (i.c.v.) or intrathecally (i.t.) on the blood glucose level were investigated in ICR mice. We found that KA administered intraperitoneally (i.p.), intracerebroventricularly (i.c.v.) or intrathecally (i.t.) increased the blood glucose and corticosterone levels, suggesting that KA-induced hyperglycemia appeared to be due to increased blood corticosterone level. In support of this finding, adrenalectomy causes a reduction of KA-induced hyperglycemia and neuronal cell death in CA3 regions of the hippocampus. In addition, pretreatment with i.c.v. or i.t. injection of CNQX (6-cyano-7-nitroquinoxaline-2, 3-dione; a non-NMDA receptor blocker) attenuated the i.p. and i.c.v. administered KA-induced hyperglycemia. KA administered i.c.v. caused an elevation of the blood corticosterone level whereas the plasma insulin level was reduced. Moreover, i.c.v. pretreatment with CNQX inhibited the decrease of plasma insulin level induced by KA i.c.v. injection, whereas the KA-induced plasma corticosterone level was further enhanced by CNQX pretreatment. Our results suggest that KA administered systemically or centrally produces hyperglycemia. A glucocorticoid system appears to be involved in KA-induced hyperglycemia. Furthermore, central non-N-methyl-D-aspartate receptors may be responsible for KA-induced hyperglycemia.

Blood glucose regulation mechanism in depressive disorder animal model during hyperglycemic states

Depression is more common among diabetes people than in the general population. In the present study, blood glucose change in depression animal model was characterized by various types of hyperglycemia models such as d-glucose-fed-, immobilization stress-, and drug-induced hyperglycemia models. First, the ICR mice were enforced into chronic restraint stress for 2h daily for 2 weeks to produce depression animal model. The animals were fed with d-glucose (2g/kg), forced into restraint stress for 30min, or administered with clonidine (5μg/5μl) supraspinally or spinally to produce hyperglycemia. The blood glucose level in depression group was down-regulated compared to that observed in the normal group in d-glucose-fed-, restraint stress-, and clonidine-induced hyperglycemia models. The up-regulated corticosterone level induced by d-glucose feeding or restraint stress was reduced in the depression group while the up-regulation of plasma corticosterone level is further elevated after i.t. or i.c.v. clonidine administration in the depression group. The up-regulated insulin level induced by d-glucose feeding or restraint stress was reduced in the depression group. On the other hand, blood corticosterone level in depression group was up-regulated compared to the normal group after i.t. or i.c.v. clonidine administration. Whereas the insulin level in depression group was not altered when mice were administered clonidine i.t. or i.c.v. Our results suggest that the blood glucose level in depression group is down-regulated compared to the normal group during d-glucose-fed-, immobilization stress-, and clonidine-induced hyperglycemia in mice. The down-regulation of the blood glucose level might be one of the important pathophysiologic changes in depression.

Effect of sulfonylureas administered centrally on the blood glucose level in immobilization stress model

Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level.

Pertussis toxin administered spinally induces a hypoglycemic effect on normal and diabetic mice

BACKGROUND/AIMS

To show whether intrathecal (i.t.) treatment with pertussis toxin (PTX) produces a hypoglycemic effect in ICR, db/db and streptozotocin-treated mice.

METHODS

The blood glucose level (BGL) was measured after i.t. treatment with PTX, AB5 toxins and PTX subunits. Insulin or leptin levels were measured after PTX injection. The effect of PTX on the BGL was examined in adrenalectomized (ADX) mice. Glucose transporter (GLUT) levels were determined by Western blotting.

RESULTS

PTX attenuated the elevated BGL in the D-glucose-fed model in a long-term manner. Heat-labile toxin (HLT), HLT subunit B or Shiga toxin, which belong to the AB5 toxins, administered i.t. did not affect the BGL. PTX A protomer (PTX-A) or PTX B oligomers (PTX-B) injected i.t. did not have an effect on the BGL as well. However, combined treatment with PTX-A and PTX-B subunits caused a hypoglycemic effect. The leptin level was gradually reduced by PTX for up to 6 days, without affecting the insulin level. PTX administered i.t. significantly decreased the BGL further in ADX mice. Moreover, GLUT-2 (hypothalamus and pituitary gland), GLUT-4 (muscle) and GLUT-3 (adrenal gland) expression levels were increased, whereas GLUT-1 (brain cortex, liver, muscle and spinal cord), GLUT-2 (liver) and GLUT-3 (brain cortex and pituitary gland) expression levels were decreased.

DISCUSSION

Our data suggest that PTX administered spinally produces a hypoglycemic effect in a long-term manner, and PTX-induced hypoglycemia appears to be mediated by the reduction in activity of the glucocorticoid system. Furthermore, PTX may modulate the insulin level during hypoglycemia. Among GLUTs, GLUT-4 in muscle, GLUT-2 in the liver, hypothalamus and pituitary gland as well as GLUT-1 in the adrenal gland may be responsible for PTX-induced hypoglycemia.

The modulatory role of alpha-melanocyte stimulating hormone administered spinally in the regulation of blood glucose level in d-glucose-fed and restraint stress mouse models

Alpha-melanocyte stimulating hormone (α-MSH) is known as a regulator of the blood glucose homeostasis and food intake. In the present study, the possible roles of α-MSH located in the spinal cord in the regulation of the blood glucose level were investigated in d-glucose-fed and immobilization stress (IMO) mouse models. We found in the present study that intrathecal (i.t.) injection with α-MSH alone did not affect the blood glucose level. However, i.t. administration with α-MSH reduced the blood glucose level in d-glucose-fed model. The plasma insulin level was increased in d-glucose-fed model and was further increased by α-MSH, whereas α-MSH did not affect plasma corticosterone level in d-glucose-fed model. In addition, i.t. administration with glucagon alone enhanced blood glucose level and, i.t. injection with glucagon also increased the blood glucose level in d-glucose-fed model. In contrasted to results observed in d-glucose-fed model, i.t. treatment with α-MSH caused enhancement of the blood glucose level in IMO model. The plasma insulin level was increased in IMO model. The increased plasma insulin level by IMO was reduced by i.t. treatment with α-MSH, whereas i.t. pretreatment with α-MSH did not affect plasma corticosterone level in IMO model. Taken together, although spinally located α-MSH itself does not alter the blood glucose level, our results suggest that the activation of α-MSH system located in the spinal cord play important modulatory roles for the reduction of the blood glucose level in d-glucose fed model whereas α-MSH is responsible for the up-regulation of the blood glucose level in IMO model. The enhancement of insulin release may be responsible for modulatory action of α-MSH in down-regulation of the blood glucose in d-glucose fed model whereas reduction of insulin release may be responsible for modulatory action of α-MSH in up-regulation of the blood glucose in IMO model.

Protective effects of Acanthopanax divaricatus extract in mouse models of Alzheimer's disease

BACKGROUND

Acanthopanax divaricatus var. albeofructus (ADA) extract has been reported to have anti-oxidant, immunomodulatory, and anti-mutagenic activity.

MATERIALS/METHODS

We investigated the effects of ADA extract on two mouse models of Alzheimer's disease (AD); intracerebroventricular injection of β-amyloid peptide (Aβ) and amyloid precursor protein/presenilin 1 (APP/PS1)-transgenic mice.

RESULTS

Intra-gastric administration of ADA stem extract (0.25 g/kg, every 12 hrs started from one day prior to injection of Aβ1-42 until evaluation) effectively blocked Aβ1-42-induced impairment in passive avoidance performance, and Aβ1-42-induced increase in immunoreactivities of glial fibrillary acidic protein and interleukin (IL)-1α in the hippocampus. In addition, it alleviated the Aβ1-42-induced decrease in acetylcholine and increase in malondialdehyde levels in the cortex. In APP/PS1-transgenic mice, chronic oral administration of ADA stem extract (0.1 or 0.5 g/kg/day for six months from the age of six to 12 months) resulted in significantly enhanced performance of the novel-object recognition task, and reduced amyloid deposition and IL-1β in the brain.

CONCLUSIONS

The results of this study suggest that ADA stem extract may be useful for prevention and treatment of AD.

Ghrelin administered spinally increases the blood glucose level in mice

Ghrelin is known as a regulator of the blood glucose homeostasis and food intake. In the present study, the possible roles of ghrelin located in the spinal cord in the regulation of the blood glucose level were investigated in ICR mice. We found that intrathecal (i.t.) injection with ghrelin (from 1 to 10 μg) caused an elevation of the blood glucose level. In addition, i.t. pretreatment with YIL781 (ghrelin receptor antagonist; from 0.1 to 5 μg) markedly attenuated ghrelin-induced hyperglycemic effect. The plasma insulin level was increased by ghrelin. The enhanced plasma insulin level by ghrelin was reduced by i.t. pretreatment with YIL781. However, i.t. pretreatment with glucagon-like peptide-1 (GLP-1; 5 μg) did not affect the ghrelin-induced hyperglycemia. Furthermore, i.t. administration with ghrelin also elevated the blood glucose level, but in an additive manner, in d-glucose-fed model. Our results suggest that the activation of ghrelin receptors located in the spinal cord plays important roles for the elevation of the blood glucose level.

The modulatory role of spinally located histamine receptors in the regulation of the blood glucose level in d-glucose-fed mice

The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (α-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with α-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, α-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.

Repaglinide, but not nateglinide administered supraspinally and spinally exerts an anti-diabetic action in d-glucose fed and streptozotocin-treated mouse models

We have recently demonstrated that some anti-diabetic drugs such as biguanide and thizolidinediones administered centrally modulate the blood glucose level, suggesting that orally administered anti-diabetic drugs may modulate the blood glucose level by acting on central nervous system. The present study was designed to explore the possible action of another class of anti-diabetic drugs, glinidies, administered centrally on the blood glucose level in ICR mice. Mice were administered intracerebroventricularly (i.c.v.) or intrathecally (i.t.) with 5 to 30 µg of repaglinide or nateglinide in D-glucose-fed and streptozotocin (STZ)-treated models. We found that i.c.v. or i.t. injection with repaglinide dose-dependently attenuated the blood glucose level in D-glucose-fed model, whereas i.c.v. or i.t. injection with nateglinide showed no modulatory action on the blood glucose level in D-glucose-fed model. Furthermore, the effect of repaglinide administered i.c.v. or i.t. on the blood glucose level in STZ-treated model was studied. We found that repaglinide administered i.c.v. slightly enhanced the blood glucose level in STZ-treated model. On the other hand, i.t. injection with repaglinide attenuated the blood glucose level in STZ-treated model. The plasma insulin level was enhanced by repaglinide in D-glucose-fed model, but repaglinide did not affect the plasma insulin level in STZ-treated model. In addition, nateglinide did not alter the plasma insulin level in both D-glucose-fed and STZ-treated models. These results suggest that the anti-diabetic action of repaglinide appears to be, at least, mediated via the brain and the spinal cord as revealed in both D-glucose fed and STZ-treated models.

Deficiency of alpha-calcitonin gene-related peptide induces inflammatory responses and lethality in sepsis

In the present study, we examined the role of alpha-calcitonin gene-related peptide (αCGRP) on expression of neuropeptides in the brain, inflammatory responses, and survival rate in septic shock condition. We examined expression of neuropeptides such as αCGRP, proopiomelanocortin (POMC), corticotrophin releasing hormone (CRH), and proenkephalin (ProENK) in the hippocampus and hypothalamus in C57BL/6 (WT) or αCGRP-/- (KO) mice subjected to sepsis. Cecal ligation and puncture (CLP) or lipopolysaccharide/D-galactosamine (LPS/D-GalN) treatment showed significant increases of hippocampal and hypothalamic αCGRP, POMC, CRH, and ProENK mRNA levels in WT mice, but not ProENK mRNA in the hypothalamus at 6h after on-set of sepsis. However, enhanced mRNA levels of POMC, CRH, and ProENK genes were not increased in the hippocampus and hypothalamus of CLP-subjected KO mice at 6h following sepsis. KO mice treated with LPS/D-GalN displayed a significant enhancement of plasma corticosterone, aspartate aminotransferase, and alanine aminotransferase levels compared to LPS/D-GalN treated WT mice at 12h after induction of sepsis. In addition, plasma levels of pro-inflammatory cytokines, such as IL-1β and TNF-α, were also further increased in KO mice compared to WT mice at 24h after CLP or LPS/D-GalN treatment. Interestingly, mRNA expressions of IL-6 and IL-10, anti-inflammatory cytokines, were synergistically enhanced in liver and lymph node of KO mice compared to WT mice at 6h after CLP. However, plasma level of IL-10 but not IL-6 was significantly decreased in KO mice compared to WT mice at 24h after CLP or LPS/D-GalN challenge. The survival rate of KO mice was significantly reduced compared to WT mice following mild (1 punch) and moderate (2 punch) CLP and LPS/D-GalN administration. Taken together, our findings suggest that the activation of αCGRP may induce other neuropeptides associated with immunomodulation at CNS level and modulate immune responses as enhancing anti-inflammatory cytokines and reducing pro-inflammatory cytokines during the sepsis.

Interleukin-1β (IL-1β) increases pain behavior and the blood glucose level: possible involvement of glucocorticoid system

The possible involvement of glucocorticoid system in interleukin-1β (IL-1β)-induced nociception and the blood glucose level was studied in ICR mice. In the first experiment, mice were treated intrathecally (i.t.) with IL-1β (100 pg). Corticotrophin releasing hormone (CRH) mRNA (hypothalamus) and c-Fos mRNA (pituitary gland, spinal cord, and the adrenal gland) levels were measured at 30, 60 and 120 min after IL-1β administration. We found that i.t. injection with IL-1β increased CRH mRNA level in the hypothalamus. The IL-1β administered i.t. elevated c-Fos mRNA levels in the spinal cord, pituitary and adrenal glands. Furthermore, i.t. administration of IL-1β significantly increased the plasma corticosterone level up to 60 min. In addition, the adrenalectomy caused the reductions of the blood glucose level and pain behavior induced by IL-1β injected i.t. in normal and D-glucose-fed groups. Furthermore, intraperitoneal (i.p.) pretreatment with RU486 (100mg/kg) attenuated the blood glucose level and pain behavior induced by IL-1β administered i.t. in normal and D-glucose-fed groups. Our results suggest that IL-1β administered i.t. increases the blood glucose level and pain behavior via an activation of the glucocorticoid system.

Effect of cholera toxin administered supraspinally or spinally on the blood glucose level in pain and d-glucose fed animal models

In the present study, the effect of intrathecal (i.t.) or intracerebroventricular (i.c.v.) administration with cholera toxin (CTX) on the blood glucose level was examined in ICR mice. The i.t. treatment with CTX alone for 24 h dose-dependently increased the blood glucose level. However, i.c.v. treatment with CTX for 24 h did not affect the blood glucose level. When mice were orally fed with D-glucose (2 g/kg), the blood glucose level reached to a maximum level at 30 min and almost returned to the control level at 120 min after D-glucose feeding. I.c.v. pretreatment with CTX increased the blood glucose level in a potentiative manner, whereas i.t. pretreatment with CTX increased the blood glucose level in an additive manner in a D-glucose fed group. In addition, the blood glucose level was increased in formalin-induced pain animal model. I.c.v. pretreatment with CTX enhanced the blood glucose level in a potentiative manner in formalin-induced pain animal model. On the other hand, i.t. pretreatment with CTX increased the blood glucose level in an additive manner in formalin-induced pain animal model. Our results suggest that CTX administered supraspinally or spinally differentially modulates the regulation of the blood glucose level in D-glucose fed model as well as in formalin-induced pain model.

Protective effects of ferulic acid in amyloid precursor protein plus presenilin-1 transgenic mouse model of Alzheimer disease

We previously reported the protective effects of long-term administration of ferulic acid against the in vivo toxicity of β-amyloid peptide administered intracerebroventricularly in mice. In the present study, we investigated the effects of ferulic acid in transgenic amyloid precursor protein (APP)swe/presenilin 1 (PS1)dE9 (APP/PS1) mouse model of Alzheimer disease (AD). Chronic (for 6 months from the age of 6 to 12 months) oral administration of ferulic acid at a dose of 5.3 mg/kg/day significantly enhanced the performance in novel-object recognition task, and reduced amyloid deposition and interleukin-1 beta (IL-1β) levels in the frontal cortex. These results suggest that ferulic acid at a certain dosage could be useful for prevention and treatment of AD.

Central anti-diabetic action of biguanide and thizolidinediones in D-glucose fed and streptozotocin-treated mouse models

BACKGROUND

In the present study, the possible anti-diabetic action of biguanide and thiazolidinediones administered supraspinally or spinally was studied in ICR mice.

METHODS

Mice were intracerebroventricular (i.c.v.) or intrathecal (i.t.) treated with 20 or 30 μg metformin, pioglitazone and rosiglitazone in d-glucose fed and streptozotocin-treated models, and blood glucose levels was measured at 30, 60 and 120 min after i.c.v. or i.t. administration.

RESULTS

We found that i.c.v. injection with metformin or rosiglitazone slightly attenuated the blood glucose level in d-glucose fed model, whereas pioglitazone showed no effect on the blood glucose level in d-glucose fed model. The i.t. administration with metformin, pioglitazone or rosiglitazone did not alter the blood glucose level in d-glucose fed model. We also assessed the possible roles of biguanide and thiazolidinedione in the regulation of the blood glucose level in streptozotocin-treated model. We found in the present study that i.c.v. or i.t. administration with metformin caused a pronounced attenuation of the blood glucose level in streptozotocin-treated model. However, rosiglitazone administered i.c.v. did not affect the blood glucose level in streptozotocin-treated model.

CONCLUSIONS

Our results suggest that the anti-diabetic actions of metformin and rosiglitazone appear to be mediated via the brain regions as revealed in d-glucose fed animal model. Furthermore, metformin administered supraspinally or spinally may be effective for treating type I diabetes mellitus as revealed in streptozotocin-treated mouse model.

Flow characteristics of LIMA radial composite sequential bypass grafting and single LIMA and saphenous vein sequential bypass grafting performed under OPCAB

AIM

The present study was aimed to compare the hemodynamic flow characteristics of LIMA radial artery composite sequential bypass grafting and with single LIMA and saphenous vein sequential bypass grafting performed by off-pump coronary artery bypass grafting (OPCAB).

METHODS

Between March 2007 and February 2008, 121 OPCAB patients were prospectively divided into two groups; Group I (N.=70, left internal thoracic artery [LITA]-left anterior descending [LAD] and Ao-SV sequential grafting), and Group II (N.=51, LITA-RA sequential grafting). The mean flow, pulsatility index (PI) and back flow (BF) were measured using the Transit-time flow meter (TTFM). In Group II, the proximal (p-LITA) and distal LITA (d-LITA) flow in relation to the RA side branch anastomosis were measured separately.

RESULTS

The mean flow and PI of the proximal SV sequential graft and that of the RA graft were 64.4 ± 37.3 mL/min and 2.6 ± 1.6 versus 27.3 ± 18.6 mL/min and 4.1 ± 4.4, respectively (P<0.05). In Group I, the mean LITA flow, PI, and BF were 26.9 ± 16.4 mL/min, 2.6 ± 1.5, and 3.1 ± 6.1% whereas in Group II those of the p-LITA were 37.3 ± 21.6 mL/min, 2.3 ± 1.0, and 2.0 ± 3.5% and the d-LITA were 18.8 ± 12.2 mL/min, 3.9 ± 3.3 and 7.4 ± 11.8% (P<0.01).

CONCLUSION

The results of the present data suggest the hemodynamic flow characteristics of composite bypass grafting to be inferior to the single LIMA and separate aorta-saphenous vein bypass grafting strategy. However, a longer follow up is warranted to assess the implications of these findings on graft durability.

The effect of TNFα secreted from macrophages activated by titanium particles on osteogenic activity regulated by WNT/BMP signaling in osteoprogenitor cells

Wear particles are the major cause of osteolysis associated with failure of implant following total joint replacement. During this pathologic process, activated macrophages mediate inflammatory responses to increase osteoclastogenesis, leading to enhanced bone resorption. In osteolysis caused by wear particles, osteoprogenitors present along with macrophages at the implant interface may play significant roles in bone regeneration and implant osteointegration. Although the direct effects of wear particles on osteoblasts have been addressed recently, the role of activated macrophages in regulation of osteogenic activity of osteoblasts has scarcely been studied. In the present study, we examined the molecular communication between macrophages and osteoprogenitor cells that may explain the effect of wear particles on impaired bone forming activity in inflammatory bone diseases. It has been demonstrated that conditioned medium of macrophages challenged with titanium particles (Ti CM) suppresses early and late differentiation markers of osteoprogenitors, including alkaline phosphatase (ALP) activity, collagen synthesis, matrix mineralization and expression of osteocalcin and Runx2. Moreover, bone forming signals such as WNT and BMP signaling pathways were inhibited by Ti CM. Interestingly, TNFα was identified as a predominant factor in Ti CM to suppress osteogenic activity as well as WNT and BMP signaling activity. Furthermore, Ti CM or TNFα induces the expression of sclerostin (SOST) which is able to inhibit WNT and BMP signaling pathways. It was determined that over-expression of SOST suppressed ALP activity, whereas the inhibition of SOST by siRNA partially restored the effect of Ti CM on ALP activity. This study highlights the role of activated macrophages in regulation of impaired osteogenic activity seen in inflammatory conditions and provides a potential mechanism for autocrine regulation of WNT and BMP signaling mediated by TNFα via induction of SOST in osteprogenitor cells.

Time-resolved measurements of PM2.5 carbonaceous aerosols at Gosan, Korea

In order to better understand the characteristics of atmospheric carbonaceous aerosol at a background site in Northeast Asia, semicontinuous organic carbon (OC) and elemental carbon (EC), and time-resolved water-soluble organic carbon (WSOC) were measured by a Sunset OC/ EC and a PILS-TOC (particle-into-liquid sampler coupled with an online total organic carbon) analyzer, respectively, at the Gosan supersite on Jeju Island, Korea, in the summer (May 28-June 17) and fall (August 24-September 30) of 2009. Hourly average OC concentration varied in the range of approximately 0.87-28.38 microgC m-3, with a mean of 4.07+/- 2.60 microgC m-3, while the hourly average EC concentration ranged approximately from 0.04 to 8.19 .microgC m-3, with a mean of 1.35 +/- 0.71 microgC m-3, from May 28 to June 17, 2009. During the fall season, OC varied in the approximate range 0.9-9.6 microgC m-3, with a mean of 2.30 +/-0.80 microgC m-3, whereas EC ranged approximately from 0.01 to 5.40 microgC m-3, with a mean of 0.66 +/- 0.38 microgC m-3. Average contributions of EC to TC and WSOC to OC were 26.0% +/- 9.7% and 20.6% +/-7.4%, and 37.6% +/- 23.5% and 57.2% +/- 22.2% during summer and fall seasons, respectively. As expected, clear diurnal variation of WSOC/OC was found in summer, varying from 0.22 during the nighttime up to 0.72 during the daytime, mainly due to the photo-oxidation process. In order to investigate the effect of air mass pathway on the characteristics of carbonaceous aerosol, 5-day back-trajectory analysis was conducted using the HYSPLIT model. The air mass pathways were classified into four types: Continental (CC), Marine (M), East Sea (ES) and Korean Peninsula (KP). The highest OC/EC ratio of 3.63 was observed when air mass originated from the Continental area (CC). The lowest OC/EC ratio of 0.79 was measured when air mass originated from the Marine area (M). A high OC concentration was occasionally observed at Gosan due to local biomass burning activities. The contribution of secondary OC to total OC varied approximately between 8.4% and 32.2% and depended on air mass type.

Lactosylceramide Mediates the Expression of Adhesion Molecules in TNF-α and IFNγ-stimulated Primary Cultured Astrocytes

Here we have investigated how lactosylceramide (LacCer) modulates gene expression of adhesion molecules in TNF-α and IFNγ (CM)-stimulated astrocytes. We have observed that stimulation of astrocytes with CM increased the gene expression of ICAM-1 and VCAM-1. D-Threo-1-phenyl- 2-decanoylamino-3-morpholino-1-propanol (PDMP) and N-butyldeoxynojirimycin (NBDNJ), inhibitors of glucosylceramide synthase (GLS) and LacCer synthase (galactosyltransferase, GalT-2), inhibited the gene expression of ICAM-1 and VCAM-1 and activation of their gene promoter induced by CM, which were reversed by exogenously supplied LacCer. Silencing of GalT-2 gene using its antisense oligonucleotides also attenuated CM-induced ICAM-1 and VCAM-1 expression, which were reversed by LacCer. PDMP treatment and silencing of GalT-2 gene significantly reduced CM-induced luciferase activities in NF-KB, AP-1, GAS, and STAT-3 luciferase vectors-transfected cells. In addition, LacCer reversed the inhibition of NF-KB and STAT-1 luciferase activities by PDMP. Taken together, our results suggest that LacCer may play a crucial role in the expression of ICAM-1 and VCAM-1 via modulating transcription factors, such as NF-KB, AP-1, STAT-1, and STAT-3 in CM-stimulated astrocytes.

The analgesic effects and mechanisms of orally administered eugenol

In the present study, the antinociceptive profiles of eugenol were examined in ICR mice. Eugenol administered orally (from 1 to 10 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured in the acetic acid-induced writhing test. Duration of antinociceptive action of eugenol maintained at least for 30 min. Moreover, the cumulative response time of nociceptive behaviors induced by an intraplantar formalin injection was reduced by eugenol treatment during the 2(nd) phases. Furthermore, the cumulative nociceptive response time for intrathecal injection of substance P (0.7 μg) or glutamate (20 μg) was diminished by eugenol. Intraperitoneal pretreatment with yohimbine (α2-adrenergic receptor antagonist) or naloxone (opioid receptor antagonist) attenuated antinociceptive effect induced by eugenol in the writhing test. However, methysergide (5-HT serotonergic receptor antagonist) did not affect antinociception induced by eugenol in the writhing test. Our results suggest that eugenol shows an antinociceptive property in various pain models. Furthermore, this antinociceptive effect of eugenol may be mediated by α2-adrenergic and opioidergic receptors, but not serotonergic receptor.

17β-Estradiol, aging, inflammation, and the stress response in the female heart

Heat shock proteins (HSPs) are a cardioprotective class of proteins induced by stress and regulated by the transcription factor, heat shock factor (HSF)-1. 17β-estradiol (E(2)) indirectly regulates HSP expression through rapid activation of nuclear factor-κB (NF-κB) and HSF-1 and protects against hypoxia. As males experience a loss of protective cellular responses in aging, we hypothesized that aged menopausal (old ovariectomized) rats would have an impaired HSP response, which could be prevented by immediate in vivo E(2) replacement. After measuring cardiac function in vivo, cardiac myocytes were isolated from ovariectomized adult and old rats with and without 9 weeks of E(2) replacement. Myocytes were treated with E(2) in vitro and analyzed for activation of NF-κB, HSF-1, and HSP expression. In addition, we measured inflammatory cytokine expression and susceptibility to hypoxia/reoxygenation injury. Cardiac contractility was reduced in old ovariectomized rats and could prevented by immediate E(2) replacement in vivo. Subsequent investigations in isolated cardiac myocytes found that in vitro E(2) activated NF-κB, HSF-1, and increased HSP 72 expression in adult but not old rats. In response to hypoxia/reoxygenation, myocytes from adult, but not old, rats had increased HSP 72 expression. In addition, expression of the inflammatory cytokines TNF-α and IL-1β, as well as oxidative stress, were increased in myocytes from old ovariectomized rats; only the change in cytokine expression could be attenuated by in vivo E(2) replacement. This study demonstrates that while aging in female rats led to a loss of the cardioprotective HSP response, E(2) retains its protective cellular properties.

Neuroprotective Effect of Visnagin on Kainic Acid-induced Neuronal Cell Death in the Mice Hippocampus

Visnagin (4-methoxy-7-methyl-5H-furo[3,2-g][1]-benzopyran-5-one), which is an active principle extracted from the fruits of Ammi visnaga, has been used as a treatment for low blood-pressure and blocked blood vessel contraction by inhibition of calcium influx into blood cells. However, the neuroprotective effect of visnagin was not clearly known until now. Thus, we investigated whether visnagin has a neuroprotective effect against kainic acid (KA)-induced neuronal cell death. In the cresyl violet staining, pre-treatment or post-treatment visnagin (100 mg/kg, p.o. or i.p.) showed a neuroprotective effect on KA (0.1 µg) toxicity. KA-induced gliosis and proinflammatory marker (IL-1β, TNF-α, IL-6, and COX-2) inductions were also suppressed by visnagin administration. These results suggest that visnagin has a neuroprotective effect in terms of suppressing KA-induced pathogenesis in the brain, and that these neuroprotective effects are associated with its anti-inflammatory effects.

The regulation of blood glucose level in physical and emotional stress models: possible involvement of adrenergic and glucocorticoid systems

This study was done to determine the effect of stress on blood glucose regulation in ICR mice. The stress was induced by the electrical foot shock-witness model. Blood glucose level was found to be increased in the electrical foot shock-induced physical stress group. Furthermore, the blood glucose levels were also elevated in the emotional stress group in both physical and emotional stress groups. The blood glucose level reached maximum 30 min after stress stimulation and returned to normal level 2 h after stress stimulation in both physical and emotional stress groups. Subsequently, we observed that intraperitoneal injection of phentolamine (an α1-adrenergic receptor antagonist), yohimbine (an α2-adrenergic receptor antagonist) or RU486 (a glucocorticoid receptor blocker) significantly inhibited blood glucose level induced by both physical and emotional stress. The results of our study suggest that physical and emotional stress increases blood glucose level via activation of adrenergic and glucocorticoid system.

Activation of PPARalpha Attenuates IFNgamma and IL-1beta-induced Cell Proliferation in Astrocytes: Involvement of IL-6 Independent Pathway

The present study demonstrates the effect of fibrates, agonists of PPARalpha on cytokines-induced proliferation in primary cultured astrocytes. Alone or combination treatment with cytokines, such as IL-1beta (10 ng/ml), IFNgamma (10 ng/ml), and TNF-alpha (10 ng/ml) cause a significant increase of cell proliferation in a time-dependent manner. Treatment of astrocytes with bezafibrate and fenofibrate (0, 5, and 10 microM) reduced the IFNgamma and IL-1beta-induced cell proliferation in a dose-dependent manner. To address the involvement of IL-6 on the IFNgamma and IL-1beta-induced cell proliferation, released IL-6 level was measured. IFNgamma and IL-1beta cause an increase of released IL-6 protein level in a time-dependent manner. Furthermore, pretreatment with IL-6 antibody (0, 0.1, 1, 2.5, and 5 ng/ml) dose-dependently inhibited the IFNgamma and IL-1beta-induced cell proliferation. However, bezafibrate and fenofibrate did not affect increased mRNA and protein levels of IL-6 in IFNgamma and IL-1beta-stimulated astrocytes. Taken together, these results clearly suggest that activation of PPARalpha attenuates the IFNgamma and IL-1beta-induced cell proliferation through IL-6 independent pathway.

Possible involvement of the hypothalamic pro-opiomelanocortin gene and beta-endorphin expression on acute morphine withdrawal development

We studied the effects of supraspinally administered morphine on the expression of the hypothalamic pro-opiomelanocortin (POMC) gene and beta-endorphin. Mice were administered morphine intracerebroventricularly (i.c.v.) either once or 5 times for 5 days (once/day). A single morphine administration significantly increased the hypothalamic POMC gene and beta-endorphin expression at 2h after application in dose-dependent fashion; however, repeated morphine administration had no effect on the hypothalamic POMC gene and beta-endorphin expression. In the immunoblot and immunohistochemical study, the increase of beta-endorphin was observed in the arcuate nucleus of the hypothalamus. Moreover, the expressions of c-Fos, phosphorylated calcium/calmodulin-dependent protein kinase-IIalpha (pCaMK-IIalpha), and phosphorylated cAMP response element-binding protein (pCREB) were increased by a single i.c.v. morphine injection at various time points, but the expressions of phosphorylated extracellular signal-regulated protein kinase1/2 (pERK1/2) and phosphorylated IkappaB (pIkappaB) were not. We also found that the expressions of c-Fos, pCaMKIIalpha, and pCREB were co-localized with the POMC expression. Meanwhile, naloxone as well as muscimol and baclofen significantly attenuated the increases of the POMC gene expression induced by a single morphine administration. Furthermore, the pretreatment of muscimol and baclofen 10 min before morphine injection robustly attenuated the withdrawal behavior induced by a single morphine administration. These results imply that the hypothalamic POMC gene and beta-endorphin expression may play an important role in the development of an acute physical dependency of morphine. In that, GABAergic neurotransmission appear to be involved in the regulation of the hypothalamic POMC gene expression induced by supraspinal morphine administration.