Exocytotic release of dopamine in ventral tegmental area slices from C57BL/6 and dopamine transporter knockout mice

The present study used voltammetry to ascertain whether electrically stimulated somatodendritic dopamine release in ventral tegmental area slices from C57BL/6 and dopamine transporter knockout mice was due to exocytosis or dopamine transporter reversal, as has been debated. The maximal concentration of electrically evoked dopamine release was similar between ventral tegmental area slices from dopamine transporter knockout and C57BL/6 mice. Dopamine transporter blockade (10 μM nomifensine) in slices from C57BL/6 mice inhibited dopamine uptake but did not alter peak evoked dopamine release. In addition, dopamine release and uptake kinetics in ventral tegmental area slices from dopamine transporter knockout mice were unaltered by the norepinephrine transporter inhibitor, desipramine (10 μM), or the serotonin transporter inhibitor, fluoxetine (10 μM). Furthermore, maximal dopamine release in ventral tegmental area slices from both C57BL/6 and dopamine transporter knockout mice was significantly decreased in response to Na⁺ channel blockade by 1 μM tetrototoxin, removal of Ca²⁺ from the perfusion media and neuronal vesicular monoamine transporter inhibition by RO-04-1284 (10 μM) or tetrabenazine (10 and 100 μM). Finally, the glutamate receptor antagonists AP-5 (50 and 100 μM) and CNQX (20 and 50 μM) had no effect on peak somatodendritic dopamine release in C57BL/6 mice. Overall, these data suggest that similar mechanisms, consistent with exocytosis, govern electrically evoked dopamine release in ventral tegmental area slices from C57BL/6 and dopamine transporter knockout mice.     

Differential modulation of cytochrome P450 1a1 by arsenite in vivo and in vitro in C57BL/6 mice

Heavy metals, typified by arsenite (As(III)), have been implicated in altering the carcinogenicity of aryl hydrocarbon receptor (AhR) ligands, typified by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), by modulating the induction of the Cyp1a1 enzyme, but the mechanism remains unresolved. In this study, the effects of As(III) on Cyp1a1 expression and activity were investigated in C57BL/6 mouse livers and isolated hepatocytes. For this purpose, C57BL/6 mice were injected intraperitoneally with As(III) (12.5 mg/kg) in the absence and presence of TCDD (15 μg/kg) for 6 and 24 h. Furthermore, isolated hepatocytes from C57BL/6 mice were treated with As(III) (1, 5, and 10 μM) in the absence and presence of TCDD (1 nM) for 3, 6, 12, and 24 h. At the in vivo level, As(III) decreased the TCDD-mediated induction of Cyp1a1 mRNA at 6 h while potentiating its mRNA, protein, and catalytic activity levels at 24 h. At the in vitro level, As(III) decreased the TCDD-mediated induction of Cyp1a1 mRNA in a concentration- and time-dependent manner. Moreover, As(III) decreased the TCDD-mediated induction of Cyp1a1 protein and catalytic activity levels at 24 h. Interestingly, As(III) increased the serum hemoglobin (Hb) levels in animals treated for 24 h. Upon treatment of isolated hepatocytes with Hb alone, there was an increase in the nuclear accumulation of AhR and AhR-dependent luciferase activity. Furthermore, Hb potentiated the TCDD-induced AhR-dependent luciferase activity. Importantly, when isolated hepatocytes were treated for 5 h with As(III) in the presence of TCDD and the medium was then replaced with new medium containing Hb, there was potentiation of the TCDD-mediated effect. Taken together, these results demonstrate for the first time that there is a differential modulation of the TCDD-mediated induction of Cyp1a1 by As(III) in C57BL/6 mouse livers and isolated hepatocytes. Thus, this study implicates Hb as an in vivo-specific modulator.     

Oxytocin induces penile erection and yawning when injected into the bed nucleus of the stria terminalis: Involvement of glutamic acid,dopamine, and nitric oxide

Oxytocin (5–100 ng), but not Arg⁸-vasopressin (100 ng), injected unilaterally into the bed nucleus of the stria terminalis (BNST) induces penile erection and yawning in a dose-dependent manner in male rats. The minimal effective dose was 20 ng for penile erection and 5 ng for yawning. Oxytocin responses were abolished not only by the oxytocin receptor antagonist d(CH₂)₅Tyr(Me)²-Orn⁸-vasotocin (1 μg), but also by (+) MK-801 (1 μg), an excitatory amino acid receptor antagonist of the N-methyl-d-aspartic acid (NMDA) subtype, SCH 23390 (1 μg), a D1 receptor antagonist, but not haloperidol (1 μg), a D2 receptor antagonist, and SMTC (40 μg), an inhibitor of neuronal nitric oxide synthase, injected into the BNST 15 min before oxytocin. Oxytocin-induced penile erection, but not yawning, was also abolished by CNQX (1 μg), an excitatory amino acid receptor antagonist of the AMPA subtype. In contrast, oxytocin responses were not reduced by bicuculline (20 ng), a GABA_A receptor antagonist, phaclofen (5 μg), a GABA_B receptor antagonist, CP 376395, a CRF receptor-1 antagonist (5 μg), or astressin 2B, a CRF receptor-2 antagonist (150 ng). Considering the ability of NMDA (100 ng) to induce penile erection and yawning when injected into the BNST and the available evidence showing possible interaction among oxytocin, glutamic acid, and dopamine in the BNST, oxytocin possibly activates glutamatergic neurotransmission in the BNST. This in turn leads to the activation of neural pathways projecting back to the paraventricular nucleus, medial preoptic area, ventral tegmental area, and/or ventral subiculum/amygdala, thereby inducing penile erection and yawning.     

IL-10 deficiency augments acute lung but not liver injury in hemorrhagic shock

In hemorrhagic shock and trauma, patients are prone to develop systemic inflammation with remote organ dysfunction, which is thought to be caused by pro-inflammatory mediators. This study investigates the role of the immuno-modulatory cytokine IL-10 in the development of organ dysfunction following hemorrhagic shock. Male C57/BL6 and IL-10 KO mice were subjected to volume controlled hemorrhagic shock for 3 h followed by resuscitation. Animals were either sacrificed 3 or 24 h after resuscitation. To assess systemic inflammation, serum IL-6, IL-10, KC, and MCP-1 concentrations were measured with the Luminex? multiplexing platform; acute lung injury (ALI) was assessed by pulmonary myeloperoxidase (MPO) activity and lung histology and acute liver injury was assessed by hepatic MPO activity, hepatic IL-6 levels, and serum ALT levels. There was a trend towards increased IL-6 and KC serum levels 3 h after resuscitation in IL-10 KO as compared to C57/BL6 mice; however this did not reach statistical significance. Serum MCP-1 levels were significantly increased in IL-10 KO mice 3 and 24 h following resuscitation as compared to C57/BL6 mice. In IL-10 KO mice, pulmonary MPO activity was significantly increased 3 h following resuscitation and after 24 h histological signs of acute lung injury were more apparent than in C57/BL6 mice. In contrast, no significant differences in any liver parameters were detected between IL-10 KO and C57/BL6 mice. Our data indicate that an endogenous IL-10 deficiency augments acute lung but not liver injury following hemorrhagic shock.     

Synthesis and carbonic anhydrase inhibitory properties of sulfamides structurally related to dopamine

A series of novel sulfamides incorporating the dopamine scaffold were synthesized. Reaction of amines and tert-butyl-alcohol/benzyl alcohol in the presence of chlorosulfonyl isocyanate (CSI) afforded sulfamoyl carbamates, which were converted to the title compounds by treatment with trifluoroacetic acid or by palladium-catalyzed hydrogenolysis. Inhibition of six α-carbonic anhydrases (CAs, EC 4.2.1.1), that is, CA I, CA II, CA VA, CA IX, CA XII and CA XIV, and two β-CAs from Candida glabrata (CgCA) and Mycobacterium tuberculosis (Rv3588) with these sulfamides was investigated. All CA isozymes were inhibited in the low micromolar to nanomolar range by the dopamine sulfamide analogues. K_is were in the range of 0.061–1.822 μM for CA I, 1.47–2.94 nM for CA II, 2.25–3.34 μM for CA VA, 0.041–0.37 μM for CA IX, 0.021–1.52 μM for CA XII, 0.007–0.219 μM for CA XIV, 0.35–5.31 μM for CgCA and 0.465–4.29 μM for Rv3588. The synthesized sulfamides may lead to inhibitors targeting medicinally relevant CA isoforms with potential applications as antiepileptic, antiobesity antitumor agents or anti-infective.     

Propentophylline increases striatal dopamine release but dampens methamphetamine-induced dopamine dynamics: A microdialysis study

While there are currently no medications approved for methamphetamine (METH) addiction, it has been shown that propentofylline (PPF), an atypical methylxanthine, can suppress the rewarding effects of methamphetamine (METH) in mice. This experiment studied the interactions of PPF with METH in striatal dopaminergic transmission. Herein, the impact of PPF (10–40 mM, intrastriatally perfused (80 min) on the effect of METH (5 mg/kg, i.p.) on striatal dopamine (DA) release was evaluated using brain microdialysis in Sprague–Dawley adult rats. METH was injected at the 60 min time point of the 80 min PPF perfusion. The extracellular levels of DA and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined using high performance liquid chromatography with electrochemical detection (HPLC-ED). PPF induced a concentration-dependent increase in DA release beginning 30 min after the onset of PPF perfusion. DA peak levels evoked by 40 mM PPF were similar to those induced by 5 mg/kg METH i.p. Only the highest concentration of PPF decreased the METH-induced DA peak (circa 70%). The significant decreases in extracellular levels of DOPAC and HVA evoked by METH were partially blocked by 10 and 20 mM PPF. Although 40 mM of PPF also partially blocked the METH-induced DOPAC decrease, it completely blocked HVA depletion after a transient increase in HVA levels in METH-treated rats. Data indicates for the first time that while PPF increases presynaptic striatal DA dynamics it attenuates METH-induced striatal DA release and metabolism.     

Stimulation by neurotensin of dopamine and 5-hydroxytryptamine (5-HT) release from rat prefrontal cortex: Possible role of NTR1 receptors in neuropsychiatric disorders

The modulation of cortical dopaminergic and serotonergic neurotransmissions by neurotensin (NT) was studied by measuring the release of dopamine (DA) and 5-hydroxytryptamine (5-HT) from the prefrontal cortex (PFC) of freely moving rats. The samples were collected via transversal microdialysis. Dopamine and 5-HT levels in the dialysate were measured using high-performance liquid chromatography (HPLC) with an electrochemical detector. Local administration of neurotensin (1 μM or 0.1 μM) in the PFC via the dialysis probe produced significant, long-lasting, and concentration-dependent increase in the extracellular release of DA and 5-HT. The increase produced by 1 μM neurotensin reached a maximum of about 210% for DA and 340% for 5-HT. A high-affinity selective neurotensin receptor (NTR1) antagonist {2-[(1-(7-chloro-4-quinolinyl)-5-(2,6-dimethoxyphenyl)pyrazol-3yl)carbonylamino tricyclo (3.3.1.1.^3.7) decan-2-carboxylic acid} (SR 48692), perfused locally at a concentration of 0.1 μM and 0.5 μM in the PFC antagonized the effects of 1 μM neurotensin. Our in vivo neurochemical results indicate, for the first time, that neurotensin is able to regulate cortical dopaminergic and serotonergic neuronal activity in freely moving rats. These effects are possibly mediated by interactions of neurotensin with neurons releasing DA or 5-HT, projecting to the PFC from the ventrotegmental area (VTA) and from the dorsal raphe nuclei (DRN), respectively. The potentiating effects of neurotensin on DA and 5-HT release in the PFC are regulated by NTR1 receptors, probably located on dopaminergic and serotonergic nerve terminals or axons.     

Synthesis and biological evaluation of novel 3,4-diaryl lactam derivatives as triple reuptake inhibitors

A series of 3,4-diarylpyrrolidin-2-one was designed, prepared and evaluated as triple reuptake inhibitors for antidepressant. Most compounds exhibited comparable in vitro efficacy as norepinephrine and dopamine transporter reuptake inhibitors. Especially, 2i showed better potency than GBR-12909 (IC₅₀ = 14 nM) which was used as reference compound for dopamine transporter. In addition, 2a and 2b showed inhibition (5.17 μM–85.6 nM) for three transporters.     

Mechanism of dopamine D2 receptor-induced Ca2 + release in PC-12 cells

Intracellular Ca^2 + levels are tightly regulated in the neuronal system. The loss of Ca^2 + homeostasis is associated with many neurological diseases and neuropsychiatric disorders such as Parkinson's, Alzheimer's, and schizophrenia. We investigated the mechanisms involved in intracellular Ca^2 + signaling in PC-12 cells. The stimulation of NGF-differentiated PC-12 cells with 3 μM ATP caused an early Ca^2 + release followed by a delayed Ca^2 + release. The delayed Ca^2 + release was dependent on prior ATP priming and on dopamine secretion by PC-12 cells. Delayed Ca^2 + release was abolished in the presence of spiperone, suggesting that it is due to the activation of D2 dopamine receptors (D2R) by dopamine secreted by PC-12 cells. This was shown to be independent of PKA activation but dependent on PLC activity. An endocytosis step was required for inducing the delayed Ca^2 + release. Given the importance of calcyon in clathrin-mediated endocytosis, we verified the role of this protein in the delayed Ca^2 + release phenomenon. siRNA targeting of calcyon blocked the delayed Ca^2 + release, decreased ATP-evoked IP₃R-mediated Ca^2 + release, and impaired subsequent Ca^2 + oscillations. Our results suggested that calcyon is involved in an unknown mechanism that causes a delayed IP₃R-mediated Ca^2 + release in PC-12 cells. In schizophrenia, Ca^2 + dysregulation may depend on the upregulation of calcyon, which maintains elevated Ca^2 + levels as well as dopamine signaling.     

Discovery of a novel phenylethyl benzamide glucokinase activator for the treatment of type 2 diabetes mellitus

Novel benzamide derivatives were synthesized and tested at in vitro assay by measuring fold increase of glucokinase activity at 5.0 mM glucose concentration. Among the prepared compounds, YH-GKA was found to be an active glucokinase activator with EC₅₀ of 70 nM. YH-GKA showed similar glucose AUC reduction of 29.6% (50 mg/kg) in an OGTT study with C57BL/J6 mice compared to 29.9% for metformin (300 mg/kg). Acute treatment of the compound in C57BL/J6 and ob/ob mice elicited basal glucose lowering activity. In subchronic study with ob/ob mice, YH-GKA showed significant decrease in blood glucose levels and no adverse effects on serum lipids or body weight. In addition, YH-GKA exhibited high bioavailability and moderate elimination in preclinical species.     

Comparison of Serotonin and Dopamine Release in Substantia Nigra and Ventral Tegmental Area: Region and Species Differences

Abstract: In this study, we compare the electrically evoked, somatodendritic release of dopamine (DA) with axonal release of serotonin (5-HT) in the substantia nigra (SN) and ventral tegmental area (VTA) in vitro by using fast-scan cyclic voltammetry with carbon-fibre microelectrodes. Furthermore, we have examined transmitter release in these regions in guinea-pig compared with rat. Somatodendritic DA was released, as shown previously, in guinea-pig VTA, SN pars compacta (SNc), and occasionally in SN pars reticulata (SNr). 5-HT was rarely released, except in SNr, where nonetheless it only contributed to <30% of amine signals. In rat midbrain, somatodendritic DA release was evoked to a similar extent as in guinea-pig. However, a clear species difference was apparent; i.e., 5-HT and DA were detected equally in rat SNc, whereas in rat SNr, 5-HT was the predominant transmitter detected. Nevertheless, electrically evoked extracellular concentrations of 5-HT in SNc and SNr were, respectively, seven- and fourfold less than DA in SNc. 5-HT release was low in all regions in neonatal rat slices before the maturation of 5-HT terminals. Hence, axonal 5-HT transmission in midbrain exhibits both species and site selectivity. Moreover, whereas somatodendritic DA release is conventionally regarded as modest compared with axon terminal release in striatum, somatodendritic DA release can result in significantly greater extracellular levels than a transmitter released from axon terminals in the same locality.     

Co-activation of synaptic and extrasynaptic NMDA receptors by neuronal insults determines cell death in acute brain slice

Overactivation of NMDA receptors is linked to cell death during neuronal insults. However the precise role of synaptic and extrasynaptic NMDA receptors remains to be further determined. In this study, we used the acute brain slice to examine the contributions of synaptic and extrasynaptic NMDA receptors to neuronal death. By activation of synaptic NMDA receptors with bath application of 100 μM bicuculline in acute brain slices, we observed a significant up-regulation in activation of neuronal survival-related signaling (p-CREB, p-ERK1/2 and p-AKT), without an obvious increase of LDH release and neuronal death. Interestingly, activation of extrasynaptic NMDA receptors alone by high dose of glutamate (200 μM) following blockade of synaptic NMDA receptors with co-application of 20 μM MK801 and 100 μM bicuculline, we failed to observe inhibition of neuronal survival signaling and neuronal damage. In contrast, co-activation of synaptic and extrasynaptic NMDA receptors by applying 200 μM glutamate or oxygen–glucose deprivation (OGD) to acute brain slices for 30 min, we observed a significant inhibition of CREB, ERK1/2 and AKT activation, an increase of LDH release and neuronal condensation. Together, co-activation of synaptic and extrasynaptic NMDA receptors by neuronal insults contributes to cell death in acute brain slice.     

Lecithin/cholesterol acyltransferase modulates diet-induced hepatic deposition of triglycerides in mice

Lecithin/cholesterol acyltransferase (LCAT) is responsible for the esterification of the free cholesterol of plasma lipoproteins. Here, we investigated the involvement of LCAT in mechanisms associated with diet-induced hepatic triglyceride accumulation in mice. LCAT-deficient (LCAT^?/?) and control C57BL/6 mice were placed on a Western-type diet (17.3% protein, 48.5% carbohydrate, 21.2% fat, 0.2% cholesterol, 4.5 kcal/g) for 24 weeks, then histopathological and biochemical analyses were performed. We report that, in our experimental setup, male LCAT^?/? mice are characterized by increased diet-induced hepatic triglyceride deposition and impaired hepatic histology and architecture. Mechanistic analyses indicated that LCAT deficiency was associated with enhanced intestinal absorption of dietary triglycerides (3.6±0.5 mg/dl per minute for LCAT^?/? vs. 2.0±0.7 mg/dl per minute for C57BL/6 mice; P<.05), accelerated clearance of postprandial triglycerides and a reduced rate of hepatic very low density lipoprotein triglyceride secretion (9.8±1.1 mg/dl per minute for LCAT^?/? vs. 12.5±1.3 mg/dl per minute for C57BL/6 mice, P<.05). No statistical difference in the average daily food consumption between mouse strains was observed. Adenovirus-mediated gene transfer of LCAT in LCAT^?/? mice that were fed a Western-type diet for 12 weeks resulted in a significant reduction in hepatic triglyceride content (121.2±5.9 mg/g for control infected mice vs. 95.1±5.8 mg/g for mice infected with Ad-LCAT, P<.05) and a great improvement of hepatic histology and architecture. Our data extend the current knowledge on the functions of LCAT, indicating that LCAT activity is an important modulator of processes associated with diet-induced hepatic lipid deposition.     

Novel spiropiperidine-based stearoyl-CoA desaturase-1 inhibitors: Identification of 1′-{6-[5-(pyridin-3-ylmethyl)-1,3,4-oxadiazol-2-yl]pyridazin-3-yl}-5-(trifluoromethyl)-3,4-dihydrospiro[chromene-2,4′-piperidine]

Cyclization of the benzoylpiperidine in lead compound 2 generated a series of novel and highly potent spiropiperidine-based stearoyl-CoA desaturase (SCD)-1 inhibitors. Among them, 1′-{6-[5-(pyridin-3-ylmethyl)-1,3,4-oxadiazol-2-yl]pyridazin-3-yl}-5-(trifluoromethyl)-3,4-dihydrospiro[chromene-2,4′-piperidine] (19) demonstrated the most powerful inhibitory activity against SCD-1, not only in vitro but also in vivo (C57BL/6 J mice). With regard to the pharmacological evaluation, 19 showed powerful reduction of the desaturation index in the plasma of C57BL/6 J mice on a non-fat diet after a 7-day oral administration (q.d.) without causing notable abnormalities in the eyes or skin up to the highest dose (3 mg/kg) in our preliminary analysis.     

Co-treating with arecoline and 4-nitroquinoline 1-oxide to establish a mouse model mimicking oral tumorigenesis

The aim of this study was to establish an effective mouse model of oral cancer and to use this model to identify potential markers of oral tumor progression. C57BL/6JNarl mice were treated with arecoline, 4-nitroquinoline 1-oxide (4-NQO), or both arecoline and 4-NQO in high and low doses for 8 weeks to induce oral tumor. The induced oral lesions were observed for 20 weeks to assess the efficiency of cancer induction and survival rate of the mice. In addition, two target proteins that are frequently overexpressed during tongue cancer tumorigenesis, αB-crystallin and Hsp27, were examined by immunohistochemical analysis. In mice exposed to 4-NQO (200 μg/mL) and arecoline (500 μg/mL), the tongue lesions showed evidence of hyperplasia, papilloma, dysplasia, and carcinoma, and the lesions were pathologically similar to those lesions in human oral cancer. The tongue tumor incidence rate was 100% in mice exposed to concomitant 4-NQO (200 μg/mL) and arecoline (500 μg/mL) treatment, 57% in mice exposed to 4-NQO only, and 0% in mice exposed to arecoline only. Immunohistochemical analysis demonstrated that, consistent with human studies, αB-crystallin and Hsp27 were upregulated in murine oral tumors. In conclusion, we have established a powerful animal model that enables the study of the promoting effects of arecoline on tongue tumorigenesis. Data subsequently attained from this mouse model support a role for αB-crystallin and Hsp27 as clinical markers for tumor progression.     

Some like it hot: Mouse temperature preferences in laboratory housing

In standard laboratory environments mice are housed at 20–24 °C. However, their thermoneutral zone ranges between 26 °C and 34 °C. This challenge to homeostasis is by definition stressful, and could therefore affect many aspects of physiology and behavior. We tested the hypothesis that mice under standard laboratory conditions are not housed at a preferred temperature, and predicted that this would be evident in thermotaxis and other behavioral responses to ambient cage temperature. We assessed the temperature preferences of C57BL/6J mice in standard laboratory housing from 4 to 11 weeks of age. Forty-eight mice (24 male and 24 female in groups of three) all born on the same day were randomly assigned to one of eight age treatments. One cage of males and one cage of females were tested each consecutive week. Mice were tested in a set of three connected cages with each cage's temperature set using a water bath. On days 1–3 each group of mice was acclimated to each of the three temperatures (20 °C, 25 °C, or 30 °C) in a random order. Then each group was given free access to all temperatures on days 4–6, and video taped continuously. The location of each mouse and the occurrence of three behavioral categories (Active, Inactive, and Maintenance) were recorded by instantaneous scan samples every 10 min over the 3 days, and time budgets calculated. While both sexes chose warmer temperatures overall (P < 0.001), they preferred warmer temperatures only for maintenance and inactive behavior (P < 0.001). This effect was most pronounced in females (P = 0.017). As temperature selection varied with time of day (P < 0.001), these behavioral differences cannot be due to ambient temperature dictating behavior. We conclude that C57BL/6J mice at 20–24 °C are not housed at their preferred temperature for all behaviors or genders, and that it may not be possible to select a single preferred temperature for all mice.     

Models of hemorrhagic shock: Differences in the physiological and inflammatory response

IntroductionThe hemorrhagic shock (HS) model is commonly used to initiate a systemic post-traumatic inflammatory response. Numerous experimental protocols exist and it is unclear how differences in these models affect the immune response making it difficult to compare results between studies. The aim of this study was to compare the inflammatory response of different established protocols for volume-controlled shock in a murine model.MethodsMale C57/BL6 mice 6–10 weeks and weighing 20–25 g were subjected to volume-controlled or pressure-controlled hemorrhagic shock. In the volume-controlled group 300 μl, 500 μl, or 700 μl blood was collected over 15 min and mean arterial pressure was continuously monitored during the period of shock. In the pressure-controlled hemorrhagic shock group, blood volume was depleted with a goal mean arterial pressure of 35 mmHg for 90 min. Following hemorrhage, mice from all groups were resuscitated with the extracted blood and an equal volume of lactated ringer solution. Six hours from the initiation of hemorrhagic shock, serum IL-6, KC, MCP-1 and MPO activity within the lung and liver tissue were assessed.ResultsIn the volume-controlled group, the mice were able to compensate the initial blood loss within 30 min. Approximately 800 μl of blood volume was removed to achieve a MAP of 35 mmHg (p < 0.001). No difference in the pro-inflammatory cytokine (IL-6 and KC) profile was measured between the volume-controlled groups (300 μl, 500 μl, or 700 μl). The pressure-controlled group demonstrated significantly higher cytokine levels (IL-6 and KC) than all volume-controlled groups. Pulmonary MPO activity increased with the severity of the HS (p < 0.05). This relationship could not be observed in the liver.ConclusionVolume-controlled hemorrhagic shock performed following current literature recommendations may be insufficient to produce a profound post-traumatic inflammatory response. A decrease in the MAP following blood withdrawal (300 μl, 500 μl or 700 μl) was usually compensated within 30 min. Pressure-controlled hemorrhagic shock is a more reliable for induction of a systemic inflammatory response.     

Primary alveolar echinococcosis: Course of larval development and antibody responses in intermediate host rodents with different genetic backgrounds after oral infection with eggs of Echinococcus multilocularis

We investigated parasite establishment, subsequent larval development and antibody responses in gerbils, cotton rats and 4 inbred mouse strains until 16 weeks post inoculation (p.i.) with 200 eggs of Echinococcus multilocularis. The rate of parasite establishment in the liver determined at 4 weeks p.i. was highest in DBA/2, followed by AKR/N, C57BL/10 and C57BL/6 mice, whereas gerbils harboured few parasite foci. The accurate number of liver lesions in cotton rats could not be determined due to rapid growth and advanced multivesiculation of the parasite observed at 2 weeks p.i. The course of larval development was most advanced in DBA/2 mice with mature protoscolex formation at 16 weeks p.i., followed by AKR/N harbouring metacestodes with sparsely distributed immature protoscoleces. On the other hand, C57BL/6 and C57BL/10 mice had infertile metacestodes without any protoscolex formation. The parasite growth in mice was totally slower than those in gerbils and cotton rats. Specific IgG and IgM responses against 3 types of native crude antigens of larval E. multilocularis were evaluated using somatic extracts of and vesicle fluid of metacestode, and somatic extracts from purified protoscoleces. The 4 mouse strains demonstrated basically similar kinetics with apparent IgG and IgM increases at 9 weeks p.i. and thereafter, except C57BL/10, exhibited higher levels of IgM against crude antigens at some time point of infection. On the other hand, a follow-up determination of specific IgG and IgM levels against recombinant antigens from larval E. multilocularis revealed that each mouse strain showed different antibody-level kinetics. The findings in the present study demonstrate that the course of host–parasite interactions in primary alveolar echinococcosis, caused by larval E. multilocularis, clearly varies among intermediate host rodents with different genetic backgrounds.     

Exploring LPS-induced sepsis in rats and mice as a model to study potential protective effects of the nociceptin/orphanin FQ system

The nociceptin receptor (NOP) and its ligand nociceptin/orphanin FQ (N/OFQ) have been shown to exert a modulatory effect on immune cells during sepsis. We evaluated the suitability of an experimental lipopolysaccharide (LPS)-induced sepsis model for studying changes in the nociceptin system. C57BL/6 mice BALB/c mice and Wistar rats were inoculated with different doses of LPS with or without a nociceptin receptor antagonist (UFP-101 or SB-612111). In C57BL/6 mice LPS 0.85 mg/kg injection produced no septic response, whereas 1.2 mg/kg produced a profound response within 5 h. In BALB/c mice, LPS 4 mg/kg produced no response, whereas 7 mg/kg resulted in a profound response within 24 h. In Wistar rats LPS 15 mg/kg caused no septic response in 6/10 animals, whereas 25 mg/kg resulted in marked lethargy before 24 h. Splenic interleukin-1β mRNA in BALB/c mice, and serum TNF-α concentrations in Wistar rats increased after LPS injection in a dose-dependent manner, but were undetectable in control animals, indicating that LPS had stimulated an inflammatory reaction. IL-1β and TNF-α concentrations in LPS-treated animals were unaffected by administration of a NOP antagonist. Similarly NOP antagonists had no effect on survival or expression of mRNA for NOP or ppN/OFQ (the N/OFQ precursor) in a variety of tissues. In these animal models, the dose–response curve for LPS was too steep to allow use in survival studies and no changes in the N/OFQ system occurred within 24 h. We conclude that LPS-inoculation in rodents is an unsuitable model for studying possible changes in the NOP-N/OFQ system in sepsis.     

Novel bis-2,2,6,6-tetramethylpiperidine (bis-TMP) and bis-mecamylamine antagonists at neuronal nicotinic receptors mediating nicotine-evoked dopamine release

By linking two or three mecamylamine or 2,2,6,6-tetramethylpiperidine (TMP) molecules together via a linear lipophilic bis-methylene linker or a specially designed conformationally restricted tris-linker, a series of bis- and tris-tertiary amine analogs has been synthesized and evaluated as potent antagonists at nAChRs mediating nicotine-evoked [³H]dopamine release from rat striatal slices. Compounds 7e, 14b and 16 demonstrated high potency in decreasing nicotine-evoked [³H]dopamine release (IC₅₀ = 2.2, 46, and 107 nM, respectively). The preliminary structure–activity data obtained with these new analogs suggest the importance of the length of the methylene linker in the bis-analog series. Such bis-tertiary amino analogs may provide a new strategy for the design of drugable ligands that have high inhibitory potency against nAChRs mediating nicotine-evoked dopamine release in striatum, which have been suggested to be target receptors of interest in the development of potential smoking cessation therapies.