Susceptibility of Males, but Not Females to Developing Femoral Head Osteonecrosis in Response to Alcohol Consumption

Background

We previously reported that ethanol-containing liquid diet feeding induces osteonecrosis of the femoral head in male rats. Also, it was reported that a large amount of consumed ethanol and a long-term history of drinking were risk factors for osteonecrosis of the femoral head, and that the frequency of alcohol-induced osteonecrosis of the femoral head in males was much greater than in females. The higher incidence of alcohol-induced osteonecrosis of the femoral head could be due to either higher prevalence of alcohol drinking in males or due to their potential higher sensitivity to alcohol. The aim of the study is to investigate the influence of alcohol consumption and drinking period on the development of osteonecrosis of the femoral head in rats of both sex.

Methods

All the experimental male rats were allocated to the male one-month ethanol drinking group (M1). Female rats were randomly divided into the female one- to five-months ethanol drinking groups (F1-5). All rats were fed a Lieber-DeCarli liquid diet containing 5% ethanol for one to five months.

Results

One-month feeding with the ethanol-containing liquid diet resulted in the development of osteonecrosis of the femoral head in seven of twenty in the M1 group, but none in the F1 group, although the mean intake of ethanol per body weight in the M1 group was significantly lower than that in the F1 group. Furthermore, long drinking periods with a large amount of ethanol intake in the F2-5 groups did not induce osteonecrosis of the femoral head.

Conclusion

The present study shows that lower alcohol consumption over short periods of time that were sufficient to induce osteonecrosis of the femoral head in males had no effect on females. Even with greater alcohol consumption and longer duration, females did not develop osteonecrosis of the femoral head. Therefore, unknown factors related to sex must be responsible for the development of this condition.

TLR4 stimulation and corticosteroid interactively induce osteonecrosis of the femoral head in rat

We previously reported that a toll-like receptor 4 signaling contributes to the development of osteonecrosis of the femoral head. Also, oxidative stress is suggested to be one of the possible pathogenesis of osteonecrosis of the femoral head. A recent study showed that toll-like receptor 4 signaling leads to oxidative stress. The aim of the present study was to evaluate whether toll-like receptor 4 stimulation and subsequent corticosteroid treatment lead to the development of osteonecrosis of the femoral head in rat, and oxidative stress is associated with it. Male Wistar rats were randomly divided into four treatment groups: Saline + Saline, Saline + Methylprednisolone, Lipopolysaccharide + Saline, Lipopolysaccharide + Methylprednisolone. Osteonecrosis of the femoral head at 14 days after the treatment was observed in 1 of 10 Lipopolysaccharide + Saline, and 5 of 10 Lipopolysaccharide + Methylprednisolone treated rats. However, it was not observed at all in the Saline + Saline and Saline + Methylprednisolone treated groups. Glutathione peroxidase activity in the liver at 1 day after the treatment was significantly increased when treated with lipopolysaccharide. However, methylprednisolone treatment reduced the activity. On the other hand, glutathione peroxidase activity in the femur did not change in any intergroup. In conclusion, the present study showed that toll-like receptor 4 stimulation by lipopolysaccharide administration strengthen incidence of corticosteroid-induced osteonecrosis of the femoral head, however, concomitant oxidative stress via toll-like receptor 4 signaling may not contribute to the development of osteonecrosis of the femoral head in rats.

Experimental drowning lung images on postmortem CT - Difference between sea water and fresh water

PURPOSE

Experimental drowning models were prepared to investigate the time-related course of lung changes using postmortem CT. This study was approved by our institutional animal ethics committee.

MATERIALS AND METHODS

Fifteen NZW rabbits (female fifteen, 2.6-4.3 (mean 3.3)kg) were divided into 3 groups: fresh water drowning (FRESH), sea water drowning (SEA), and sea water drowning with anterior chest compression (ACC). All individuals were examined by CT (Aquilion CX, Toshiba, Japan) on postmortem time course. The rabbit's head was submerged in a water bath for a total of 10 min. In ACC, cardiopulmonary resuscitation was performed for 2 min, additionally. The percentage of aerated lung volumes (%ALV=100 (aerated lung volume/total lung volume)) were statistically evaluated and the lung CT image patterns and pleural fluid appearance time were investigated.

RESULTS

All lungs had decreased their %ALV within 24h, and there were no statistical differences in and among the 3 groups. After 36 h, %ALV tended to increase in all groups, and only ACC presented a statistical difference between 1h and 36 h (p<0.005). On postmortem lung CT, all lungs presented ground-glass opacity with interstitial thickening spread pattern (100%) and no pattern change during the follow-up period. After presenting pleural space fluid collection, the %ALV tended to increase.

CONCLUSION

There were no differences among FRESH, SEA, and ACC in %ALV within 24h. Only ground-glass opacity could be detected on postmortem lung CT, experimentally.

Freezing effect on brain density in postmortem CT

Two 60-year-old males were found at their homes whose bodies had deteriorated due to putrefaction. To prevent worm invasion and minimize deterioration, dry ice was used prior to the autopsy investigation. Prior to autopsy, postmortem CT demonstrated a decreased density in brain parenchyma at the dry-iced side, and autopsy revealed deteriorated brain parenchyma with frozen effect (presented like sherbet). Moreover, the deteriorated cerebral parenchyma maintained their structure and they were evaluated by cutting. When lower CT density presents in postmortem CT, the freezing effect may need to be considered and the physician should evaluate the cadaver's postmortem condition to prevent misdiagnoses.

Involvement of μ- and δ-opioid receptor function in the rewarding effect of (±)-pentazocine

Most opioid receptor agonists have abuse potential, and the rewarding effects of opioids can be reduced in the presence of pain. While each of the enantiomers of pentazocine has a differential pharmacologic profile, (±)-pentazocine has been used clinically for the treatment of pain. However, little information is available regarding which components of pentazocine are associated with its rewarding effects, and whether the (±)-pentazocine-induced rewarding effects can be suppressed under pain. Therefore, the present study was performed to investigate the effects of pain on the acquisition of the rewarding effects of (±)-pentazocine, and to examine the mechanism of the rewarding effects of (±)-pentazocine using the conditioned place preference paradigm. (±)-Pentazocine and (-)-pentazocine, but not (+)-pentazocine, produced significant rewarding effects. Even though the rewarding effects induced by (±)-pentazocine were significantly suppressed under pain induced by formalin, accompanied by increase of preprodynorphin mRNA levels in the nucleus accumbens, a high dose of (±)-pentazocine produced significant rewarding effects under pain. In the normal condition, (±)-pentazocine-induced rewarding effects were blocked by a low dose of naloxone, whereas the rewarding effects induced by high doses of pentazocine under pain were suppressed by naltrindole (a δ-opioid receptor antagonist). Interestingly, (±)-pentazocine did not significantly affect dopamine levels in the nucleus accumbens. These findings suggest that the rewarding effects of (-)-pentazocine may contribute to the abuse potential of (±)-pentazocine through μ- as well as δ-opioid receptors, without robust activation of the mesolimbic dopaminergic system. We also found that neural adaptations can reduce the abuse potential of (±)-pentazocine under pain.

Classification of hemopericardium on postmortem CT

Postmortem CT (PMCT) is increasingly used in forensic practice, and knowledge and classification of typical hemopericardium on PMCT would help to assure correct radiological interpretation. The goal of this study was to evaluate the pericardial and pleural space fluid volumetry, and to evaluate the signs on PMCT pointing to cardiac tamponade as the cause of death, and their pitfalls. Fourteen cadavers (eleven male, three female, 49-87 [mean, 70.9] years) were examined by PMCT. The pericardial volume and pericardial findings with/without pleural space fluid collection were compared with autopsy findings. In addition, the appearance of pericardial lesions on PMCT was documented and compared with the autopsy findings. The respective volumes of pericardial space, and right and left pleural space fluid showed as 172.0-711.0 (mean 368.7) ml, 0-1830.0 (266.1) ml, 0-231.0 (75.2) ml on PMCT, and were 136.0-652.0 (311.1) ml, 0-2100 (299.0) ml, and 0-300.0 (61.3) ml on autopsy. In statistical evaluation, the pericardial space volume was significantly greater on PMCT (p<0.05), but there was no significant difference in pleural space fluid volume. The hemopericardium PMCT showed 3 patterns: double band, single band, and horizontal level, and the former two patterns presented as coagulated blood at autopsy. Single band and horizontal level patterns were thought to result from CPR-related causes and/or postmortem manipulation. In conclusion, double and single band patterns on PMCT were indicative findings of cardiac tamponade. An understanding of the pericardial PMCT appearance and its significance can help to avoid misreading, and is important for making correct radiological interpretation.

CT-guided percutaneous needle placement in forensic medicine

We have developed a technique of CT-guided needle placement in the destructed human body in forensic practice. A sixty-year-old male was found in a burned car and he was also destructed severely. Although blood was needed for the external examination, it was difficult to approach the vessels because of the severely burned condition of the cadaver. Thus, we attempted to obtain a blood sample from a vessel using a CT-guided technique. Postmortem CT demonstrated the presence of blood-containing vessels in the pelvis. Indeed, CT-guided needle placement had no difficulty with surface markers, table location, or depth measurement from the surface. CT-guide needle placement is a feasible and reliable technique, so that when the tissue/blood sample is at risk of being spoiled, CT-guided needle placement could be a substitute for conventional sampling techniques.

New pitfalls of high-density postmortem computed tomography

An 80-year-old female was transferred to the hospital due to a traffic accident. Multiple cranial bone fractures with intracranial hemorrhage and intracranial air were detected. Despite treatment, the patient died after 6h. Twenty-one hours after the patient died, her whole body was scanned by postmortem CT, and a region of high density was detected within the left putamen. The autopsy revealed a cerebral contusion and multiple skull base fractures. Moreover, superabsorbent polymers (SAPs) were found within the left lateral ventricle and adjacent to the putamen, which appeared as a high-density lesion on postmortem CT at the left putamen, where the SAPs were compacted. Both ante- and postmortem conditions should be considered to prevent misdiagnoses based only on postmortem CT.

Experimental rat model for alcohol-induced osteonecrosis of the femoral head

Alcohol-induced osteonecrosis of the femoral head (ONFH) is observed in alcohol abusers and patients with alcoholic fatty liver disease. It has been reported that Toll-like receptor 4 (TLR4) signalling plays a crucial role in the pathogenesis of alcoholic fatty liver disease. We previously reported a corticosteroid-induced ONFH rat model, and suggested that TLR4 signalling contributes to the pathogenesis of ONFH. Thus, it is thought that the pathogenesis of alcohol-induced ONFH is probably similar to that of corticosteroid-induced ONFH. The aim of this study was to develop a new animal model for alcohol-induced ONFH and to evaluate the relationship between the pro-inflammatory response via TLRs and the development of ONFH in rats. Male Wistar rats were fed a Lieber–DeCarli liquid diet containing 5% ethanol (experimental group) or dextran (control group) for 1–24 weeks. Histopathological and biochemical analyses were performed. Feeding the ethanol-containing liquid diet resulted in the development of ONFH with hepatic steatosis, hepatic dysfunction and hyperlipidaemia, whereas feeding the dextran-containing diet did not cause ONFH. However, we could not recognize any relationship between the pro-inflammatory response via TLR4 and the development of alcohol-induced ONFH. Thus in this study we have developed a new rat model for alcohol-induced ONFH based on the feeding of an ethanol liquid diet. ONFH was observed within seven days from the start of feeding with 5% ethanol-containing liquid diet. Although this was linked to hepatic steatosis, a TLR4 association was not a feature of this model.

Weight bearing does not contribute to the development of osteonecrosis of the femoral head

The hip joint is one of the major structures in the human body and the resultant force acting through the hip joint is 300% of body weight. Therefore, weight bearing, as a cause of ischaemia, may contribute to the development of non-traumatic osteonecrosis of the femoral head (ONFH). However, it remains unclear whether weight bearing is related to the development of non-traumatic ONFH. Therefore the aim of this study was to clarify the role of weight bearing in the development of non-traumatic ONFH. Non-weight-bearing (NWB) rats were tail suspended to prevent any weight coming to bear on the hindlimbs from day 1 to the time of sacrifice. The weight-bearing (WB) group rats were also housed individually, although without tail suspension. All rats were injected with lipopolysaccharide and methylprednisolone to promote the development of non-traumatic ONFH. All animals were sacrificed three weeks after the final methylprednisolone injection. Histopathological analysis was performed. Osteonecrosis of the femoral head was observed not only in the NWB but also in the WB rats; however, no osteonecrosis of the humeral head was observed in either group. We confirmed that non-traumatic ONFH developed in NWB rats, suggesting that weight bearing does not contribute to the development of non-traumatic ONFH in rats.

The suppression of TRIM21 and the accumulation of IFN-α play crucial roles in the pathogenesis of osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH), the pathogenesis of which remains unclear, has been observed in autoimmune disease patients treated with corticosteroids. Recently, it has been shown that anti-tripartite motif-containing 21 (TRIM21) autoantibodies, which are often present in patients with systemic lupus erythematosis and Sjögren's syndrome, inhibit the E3 ligase activity of TRIM21. TRIM21 negatively regulates nuclear factor-κB (NF-κB) and interferon regulatory factors (IRFs) 3 and 7, three downstream transcription factors, via toll-like receptor 4 signaling. The aim of this study was to clarify the role of TRIM21 in the pathogenesis of ONFH using an animal model. Male Wistar rats were injected with lipopolysaccharide (LPS) twice and with methylprednisolone (MPSL) or saline three times. N-acetyl cysteine (NAC) was administered either concurrently with MPSL or once daily for the 3 days following the last MPSL injection. The incidence of ONFH in the MPSL group was 23.5%. Co-treatment of NAC and MPSL increased the incidence of ONFH to 55.6%. MPSL treatment decreased the activity of NF-κB in the liver and significantly increased the activity of both IRF3 and IRF7. No significant differences were observed in the activity of any of these three transcription factors between the MPSL and the co-treatment groups. In the femoral head, co-treatment with NAC and MPSL significantly decreased the expression of TRIM21 at 3 h and significantly increased the expression of interferon (IFN)-α at 24 h when compared with the MPSL group. IFN-α is known to induce cell death. These findings suggest that the suppression of TRIM21 in the femoral head causes an accumulation of IFN-α, which in turn leads to the development of ONFH. In conclusion, the suppression of TRIM21 resulting from altered NF-κB and IRF homeostasis accelerates the ONFH in rats treated with corticosteroids following LPS administration.

Epigenetic regulation of MIR-124 under ethanol dependence and withdrawal

Withdrawal from chronic alcohol cause the persistent molecular alteration, such as changes in the release of neurotransmitter and gene expression. The alterations are thought to increase in the risk of relapse. Recent studies suggest that the gene expression regulated by histone acetylation may play an important role in the dependence of abused drugs, including of ethanol. Furthermore, miRNA, another regulator of gene expression, are also important molecules for the dependence. However, changes in the molecules under ethanol withdrawal and its relationship are poorly understood. In the present study, we investigated the expression of acetylated histone H3 and miR-124 in mouse brain at 3 days after ethanol withdrawal. 6-Week ages of C57BL/6J mice were treated with liquid diet containing ethanol for 10 days. Using the escalating ethanol dosage schedule, the mice were fed the ethanol diet as follows: 1st day: 1 w/v%: 2nd and 3rd day: 3 w/v%; 4th and 5th day: 4 w/v% and from the 6th to 10th day: 5 w/v% ethanol diet, respectively. The pair-fed control mice were given the same volume of ethanol-free liquid diet with glucose substituted in isocaloric quantities for ethanol. After feeding alcohol liquid diet, the mice showed severe withdrawal signs. The expression of acetylated histone H3 was significantly decreased in limbic forebrain at 3 days after withdrawal. We found that miR-124 also decreased in the limbic forebrain. It has been reported that Cdc42 regulates neuronal development as a target of miR-124. We found that Cdc42 protein markedly increased in both brain regions at 3 days after withdrawal. Our findings suggest that changes in the expression of miR-124 via histone acetylation leads to change the Cdc42 expression under ethanol withdrawal.

Ethanol-induced hyponatremia augments brain edema after traumatic brain injury

Alcohol consumption augments brain edema by expression of brain aquaporin-4 after traumatic brain injury. However, how ethanol induces brain aquaporin-4 expression remains unclear. Aquaporin-4 can operate with some of ion channels and transporters. Therefore, we hypothesized that ethanol may affect electrolytes through regulating ion channels, leading to express aquaporin-4. To clarify the hypothesis, we examined role of AQP4 expression in ethanol-induced brain edema and changes of electrolyte levels after traumatic brain injury in the rat. In the rat traumatic brain injury model, ethanol administration reduced sodium ion concentration in blood significantly 24 hr after injury. An aquaporin-4 inhibitor recovered sodium ion concentration in blood to normal. We observed low sodium ion concentration in blood and the increase of brain aquaporin-4 in cadaver with traumatic brain injury. Therefore, ethanol increases brain edema by the increase of aquaporin-4 expression with hyponatremia after traumatic brain injury.

Prenatal exposure to titanium dioxide nanoparticles increases dopamine levels in the prefrontal cortex and neostriatum of mice

Titanium dioxide (TiO(2)) nanoparticles are widely used in cosmetics, sunscreen and as a photocatalyst. However, little is known about the biological effect of TiO(2) nanoparticles in humans and other animals. Here, we investigated whether prenatal exposure to TiO(2) nanoparticles impacted the central nervous system in mice. We measured the levels of dopamine (DA) and its metabolites in several regions of the brain in mice using high performance liquid chromatography (HPLC). HPLC analysis showed that DA and its metabolites were increased in the prefrontal cortex and the neostriatum following prenatal exposure to TiO(2) nanoparticles. The present study highlights the possibility that maternal exposure to TiO(2) nanoparticles might influence the development of the central dopaminergic system in offspring.

Maternal exposure to nanoparticulate titanium dioxide during the prenatal period alters gene expression related to brain development in the mouse

Background

Nanotechnology is developing rapidly throughout the world and the production of novel man-made nanoparticles is increasing, it is therefore of concern that nanomaterials have the potential to affect human health. The purpose of this study was to investigate the effects of maternal exposure to nano-sized anatase titanium dioxide (TiO₂) on gene expression in the brain during the developmental period using cDNA microarray analysis combined with Gene Ontology (GO) and Medical Subject Headings (MeSH) terms information.

Results

Analysis of gene expression using GO terms indicated that expression levels of genes associated with apoptosis were altered in the brain of newborn pups, and those associated with brain development were altered in early age. The genes associated with response to oxidative stress were changed in the brains of 2 and 3 weeks old mice. Changes of the expression of genes associated with neurotransmitters and psychiatric diseases were found using MeSH terms.

Conclusion

Maternal exposure of mice to TiO₂ nanoparticles may affect the expression of genes related to the development and function of the central nervous system.

Effect of prenatal exposure to diesel exhaust on dopaminergic system in mice

Diesel exhaust (DE) is composed of particles and gaseous compounds. It has been reported that DE causes pulmonary and cardiovascular disease. We have previously reported that fetal exposure to DE had deleterious effects to the reproductive system of mice offspring. However, there is still little known about the effects of prenatal exposure to DE to the central nervous system (CNS). In the present study, we found that prenatal exposure to DE induced reduction of locomotion, furthermore, dopamine (DA) turnover was significantly decreased in the striatum and nucleus accumbens. These results suggest that prenatal exposure to DE has an effect on the CNS. Hypolocomotion could be due to a decrease in DA turnover associated with DA nervous system abnormality. The present study provides the possibility that maternally inhaled DE might influence the development of central dopaminergic system and result in behavior disorder.

Smooth muscle-associated protein 8: distribution and biological activity in the rat brain

With the use of an antiserum directed against the human smooth muscle-associated protein 8 (SMAP8) fragment SMAP8(98-138), Western blot and immunohistochemical studies revealed SMAP8 expression in the rat brain. A band with a molecular size of about 45 kDa was detected in tissues from the rat hypothalamus and a weaker band from the cortex. SMAP8 immunoreactivity (irSMAP8) was detected in neurons of the hypothalamic paraventricular, supraoptic, and supraoptic retrochiasmatic nuclei; a few irSMAP8 cells were scattered in the zona incerta as well as the cerebral cortex. Immunoreactive cell processes were detected mostly in the internal layer of the median eminence. Double labeling the hypothalamic sections with SMAP8 and vasopressin (VP) or oxytocin (OT) antiserum revealed that a population of VP- and OT-immunoreactive neurons expressed irSMAP8. The biological activity of SMAP8 in rat central neurons was assessed by the calcium microfluorimetric Fura-2 method. SMAP8 (100 nM) elevated cytosolic calcium concentrations [Ca2+]i in a population of dissociated and cultured rat hypothalamic neurons; the response was eliminated in Ca2+-free saline. This is the first evidence of irSMAP8 in a population of VP/OT-containing hypothalamic neurons in the rat, and the peptide is biologically active in hypothalamic neurons, as evidenced by mobilization of extracellular Ca2+.

Changes in central dopaminergic systems and morphine reward by prenatal and neonatal exposure to bisphenol-A in mice: evidence for the importance of exposure period

Bisphenol-A has been extensively evaluated for toxicity in a variety of tests as the most common environmental endocrine disruptors. In a previous study, we reported that exposure to bisphenol-A affects the development of the central dopaminergic system in the mouse limbic area. The present study was undertaken to investigate the relationship between the developmental toxicity of bisphenol-A and its exposure period. The exposure to bisphenol-A during either organogenesis or lactation, but not implantation and parturition, significantly enhanced the morphine-induced hyperlocomotion and rewarding effects. Furthermore, exposure to bisphenol-A during either organogenesis or lactation also produced an up-regulation of dopamine receptor function to activate G-protein in the mouse limbic forebrain. These results indicate that both organogenesis and lactation are more sensitive to the bisphenol-A-induced developmental neuronal toxicology than any other periods. In conclusion, the present data suggest that the organogenesis and lactation are the most important period to cause the alternation of dopaminergic system by bisphenol-A exposure in the mouse.

Distribution and characterization of estrogen receptor G protein-coupled receptor 30 in the rat central nervous system

The G protein-coupled receptor 30 (GPR 30) has been identified as the non-genomic estrogen receptor, and G-1, the specific ligand for GPR30. With the use of a polyclonal antiserum directed against the human C-terminus of GPR30, immunohistochemical studies revealed GPR30-immunoreactivity (irGPR30) in the brain of adult male and non-pregnant female rats. A high density of irGPR30 was noted in the Islands of Calleja and striatum. In the hypothalamus, irGPR30 was detected in the paraventricular nucleus and supraoptic nucleus. The anterior and posterior pituitary contained numerous irGPR30 cells and terminal-like endings. Cells in the hippocampal formation as well as the substantia nigra were irGPR30. In the brainstem, irGPR30 cells were noted in the area postrema, nucleus of the solitary tract, and dorsal motor nucleus of the vagus; a cluster of cells were prominently labeled in the nucleus ambiguus. Tissue sections processed with pre-immune serum showed no irGPR30, affirming the specificity of the antiserum. G-1 (100 nM) caused a large increase of intracellular calcium concentrations [Ca(2+) ](i) in dissociated and cultured rat hypothalamic neurons, as assessed by microfluorometric Fura-2 imaging. The calcium response to a second application of G-1 showed a marked homologous desensitization. Our result shows a high expression of irGPR30 in the hypothalamic-pituitary axis, hippocampal formation, and brainstem autonomic nuclei; and the activation of GPR30 by G-1 is associated with a mobilization of calcium in dissociated and cultured rat hypothalamic neurons.

Prenatal and neonatal exposure to low-dose of bisphenol-A enhance the morphine-induced hyperlocomotion and rewarding effect

Bisphenol-A has been extensively evaluated for toxicity in a variety of tests as the most common environmental endocrine disruptors. In the previous study, we reported that prenatal and neonatal exposure to high-dose of bisphenol-A affects the development of central dopaminergic system in the mouse limbic area. The present study was then undertaken to investigate whether prenatal and neonatal exposure to lower dose of bisphenol-A could change the morphine-induced several pharmacological actions such as rewarding effect and hyperlocomotion in mice. Prenatal and neonatal exposure to low-dose of bisphenol-A enhanced the morphine-induced hyperlocomotion and rewarding effect. Additionally, the treatment with bisphenol-A produced an up-regulation of dopamine receptor function to activate G-protein in the mouse limbic forebrain, which is thought to play a critical role for hyperlocomotion and rewarding effects by drugs of abuse. These findings suggest that prenatal and neonatal exposure to low-dose of bisphenol-A can potentiate the central dopamine receptor-dependent neurotransmission, resulting in the supersensitivity of the morphine-induced hyperlocomotion and rewarding effects in the mouse.

Dynamic changes in dopaminergic neurotransmission induced by a low concentration of bisphenol-A in neurones and astrocytes

One of the most common chemicals that behaves as an endocrine disruptor is the compound 4,4'-isopronylidenediphenol, called bisphenol-A (BPA). We previously reported that prenatal and postnatal exposure to BPA potentiated central dopaminergic neurotransmission, resulting in supersensitivity to psychostimulant-induced pharmacological actions. Many recent findings have supported the idea that astrocytes, which are a subpopulation of glial cells, play a critical role in neuronal transmission in the central nervous system. The present study aimed to investigate the role of neurone-astrocyte communication in the enhancement of dopaminergic neurotransmission induced by BPA. We found that treatment of mouse purified astrocytes and neurone/glia cocultures with BPA in vitro caused the activation of astrocytes, as detected by a stellate morphology and an increase in levels of glial fibrillary acidic protein. A low concentration of BPA significantly enhanced the Ca2+ responses to dopamine in both neurones and astrocytes. Furthermore, a high concentration of BPA markedly induced the activation of caspase-3, which is a marker of neuronal apoptotic cell death in mouse midbrain neurone/glia cocultures. By contrast, treatment with 17beta-oestradiol (E2) had no such effects. Prenatal and neonatal exposure to BPA led to an enhancement of the dopamine-dependent rewarding effect induced by morphine. These findings provide evidence that BPA alters dopamine responsiveness in neurones and astrocytes and that, at least in part, it may contribute to potentiate the development of psychological dependence on drugs of abuse.

[Exposure to bisphenol-A affects the rewarding system in mice]

Bisphenol-A has been extensively evaluated for toxicity in a variety of tests as the most common environmental endocrine disruptor. In the present study, we found that prenatal and neonatal exposure to bisphenol-A affects the development of the central dopaminergic system in the mouse limbic area. Additionally, this treatment with bisphenol-A produced a down-regulation of dopamine D3 receptor and an up-regulation of dopamine D1 receptor function to activate G-protein in the mouse limbic forebrain, which is thought to play a critical role for rewarding effects by drugs of abuse. We next investigated the relationship between the neurobehavioral toxicity and its exposure period. The exposure to bisphenol-A during either organogenesis or lactation, but not implantation and parturition, significantly enhanced the morphine-induced hyperlocomotion and rewarding effect. Furthermore, the exposure to bisphenol-A during either organogenesis or lactation also produced an up-regulation of dopamine D1 receptor function to activate G-protein in the mouse limbic forebrain. These results indicate that either organogenesis or lactation is more sensitive to the bisphenol-A-induced neuronal toxicity than any other periods. In conclusion, we found here that prenatal and neonatal exposure to bisphenol-A can potentiate the central dopaminergic systems, resulting in the supersensitivity of the drugs of abuse-induced rewarding effects and hyperlocomotion in the mouse. Furthermore, the organogenesis and lactation are the most important period to cause the alteration of dopaminergic system by bisphenol-A exposure in the mouse.

Neuropeptide B immunoreactivity in the central nervous system of the rat

Neuropeptide B (NPB) is a recently identified endogenous ligand for the orphan G protein-coupled receptors GPR7 and GPR8. NPB mRNA is expressed in the human, rat, and mouse brain. With the use of an antiserum directed against the rat NPB, immunoreactivity to NPB (irNPB) was detected in several discrete areas of the hypothalamus and midbrain. In the hypothalamus, irNPB cells were present in the medial preoptic area and nucleus, ventromedial preoptic nucleus, retrochiasmatic nucleus, paraventricular hypothalamic nucleus, supraoptic nucleus, accessory neurosecretory nuclei, periventricular hypothalamic nucleus, dorsomedial hypothalamic nucleus, supraoptic retrochiasmatic nucleus, lateral hypothalamic area, posterior hypothalamic area, dorsal hypothalamic area, and zona incerta. A few irNPB perikarya were noted in the arcuate nucleus, whereas a dense network of nerve fibers was present in the median eminence. In the midbrain, irNPB somata were noted in the substantia nigra (compact, reticular, medial, and lateral parts), paranigral nucleus, ventral tegmental area, interfascicular nucleus, and dorsal raphe nucleus. Neurons in the Edinger-Westphal were strongly labeled. Labeled cells were not detected in the cortex, medulla oblongata, and spinal cord; few lightly labeled cells were occasionally seen in the hippocampus. Double labeling the hypothalamic sections with NPB antiserum and vasopressin or oxytocin antibody revealed that a population of vasopressin- but not oxytocin-immunoreactive cells was irNPB. Tyrosine hydroxylase-positive neurons in the midbrain, presumably dopaminergic, were irNPB. The distribution of irNPB neurons in several areas of the hypothalamus and midbrain together with the colocalization with vasopressin or tyrosine hydroxylase suggests that the peptide may subserve neuroendocrine, autonomic, and motor functions.

[The functional change in the 5-HT1A receptor induced by stress and the role of the 5-HT1A receptor in neuroprotection]

Mice exposed to various stresses, especially restrained-stress, revealed the anxiogenic effect detected by the light-dark test. Under this condition, a remarkable decrease in [35S]GTPgammaS binding to membranes from the prefrontal cortex, amygdala and hypothalamus of restrained-stress mice stimulated by the selective 5-HT1A receptor agonist 5-carboxamidotriptamine (5-CT) was clearly observed, whereas a significant increase in [35S]GTPgammaS binding stimulated by the 5-HT1A receptor agonist was clearly observed in the dorsal raphe nuclei (DRN) of restrained-stress mice. The immunohistochemical study showed a drastic reduction in phosphorylated-CREB-like immunoreactivity in the DRN of restrained-stress mice. Furthermore, we found a drastic reduction in myelin-associated glycoprotein (MAG)-like immunoreactivity (MAG-IR) in the DRN, amygdala and hypothalamus, indicating the direct suppression of synaptic transmission in these regions. It has been accepted that GSK3beta in the Wnt signal pathway plays an important role in various neuronal functions including apoptosis, clustering of synapsin I and early growth and axonal remodeling. In the present study, the increase in protein levels of GSK3beta and phosphorylated-GSK3beta to cytosol fractions of the amygdala was noted in restrained-stress mice. Taken together, these results suggest that restrained stress may directly affect the 5-HT1A receptor-regulated synaptic transmission in the brain, leading to the expression of the anxiogenic effect in mice. It is well known that various stresses induce intracellular oxidative stress. The present study was then undertaken to investigate the effect of the stimulation of 5-HT1A receptors on oxidative stress. Treatment with H2O2 caused the activation of caspase-3-positive cells and the reduction in levels of MAG-IR in the limbic neuron/glia cocultures as compared to medium alone. The stimulation of 5-HT1A receptor by 5-CT produced a dramatic protection against H2O2-triggered activation of caspase-3 and reduction in levels of MAG-IR. These results suggest that 5-HT1A receptors were involved in the modulation of anxiety and the understanding of molecular mechanisms of 5-HT1A receptor-related cascades may pave the way for new therapeutic strategies for affective disorders.

Prenatal and neonatal exposure to bisphenol-A affects the morphine-induced rewarding effect and hyperlocomotion in mice

Bisphenol-A (BPA), one of the most common environmental endocrine disrupters, has been extensively evaluated for toxicity and carcinogenicity. However, little is still known about its action on the CNS. Here we found that prenatal and neonatal exposure to BPA resulted in the enhancement of the rewarding effect and hyperlocomotion induced by morphine in mice. Under these conditions, no change in the G-protein activation by morphine and mu-opioid receptor expression in the lower midbrain was observed by prenatal and neonatal exposure to BPA. These results suggest that chronic exposure to BPA produces the supersensitivity of the morphine-induced rewarding effect and hyperlocomotion without direct changes in mu-opioid receptor function in the lower midbrain. The present data provide further evidence that prenatal and neonatal exposure to BPA can directly influence the development of the central dopaminergic system.

Enhancement of dopamine-induced signaling responses in the forebrain of mice lacking dopamine D3 receptor

It is well known that the dopamine D(3) receptor plays a critical role in several psychological disorders, such as drug dependence. The present study was designed to investigate the influence of lacking dopamine D(3) receptors in dopamine-induced G-protein activation and Ca(2+) influx in the mouse forebrain. The deletion of dopamine D(3) receptor gene caused the enhancement of dopamine-induced G-protein activation in the limbic forebrain of dopamine D(3) receptor knockout (D(3)KO) mice. Furthermore, the dopamine-induced Ca(2+) influx was enhanced in the coculture of neuron/glia cells obtained from the forebrain of D(3)KO mice. The present data provide direct evidence that a deletion of central dopamine D(3) receptor enhances the dopamine D(1)/D(2) receptor-mediated intracellular signaling.

Functional changes in dopamine D3 receptors by prenatal and neonatal exposure to an endocrine disruptor bisphenol-A in mice

Bisphenol-A (BPA), one of the most common environmental endocrine disrupters, has been evaluated extensively for toxicity and carcinogenicity. However, little is still known about its action on the central nervous system (CNS). In the previous study, we found that prenatal and neonatal exposure to BPA markedly enhanced the rewarding effect induced by morphine. Here we found that prenatal and neonatal exposure to BPA resulted in the attenuation of dopamine D3 receptor-mediated G-protein activation by 7-OH-DPAT in the mouse limbic forebrain. This treatment also caused a significant decrease in the B(max) value of [(3)H]PD128907, a dopamine D3 receptor ligand, in this area. Under these conditions, no change in dopamine D3 receptor mRNA expression in the limbic forebrain and lower midbrain was observed by prenatal and neonatal exposure to BPA. The present data provide further evidence that prenatal and neonatal exposure to BPA leads to the reduction of functional dopamine D3 receptors without affecting the new synthesis of dopamine D3 receptors in the mouse limbic forebrain.

Disruption of the type 1 inositol 1,4,5-trisphosphate receptor gene suppresses the morphine-induced antinociception in the mouse

The present study was designed to investigate whether endoplasmic inositol 1,4,5-trisphosphate (IP3) receptor-mediated intracellular signaling pathway could be involved in the morphine-induced antinociception in the mouse. An intracerebroventricular (i.c.v.) pretreatment with xestospongin C (10-100 pmol per mouse, i.c.v.), a membrane permeable and selective antagonist for IP3 receptor, produced a dose-dependent reduction in the supraspinal antinociceptive effect produced by i.c.v. administration of morphine (0.3-10 nmol). In addition, the dose-response curve for morphine-induced antinociception was significantly shifted to the right by i.c.v. pretreatment with xestospongin C at 100 pmol. In the present study, we confirmed that the IP3R1 mRNA in opisthonos (opt) heterozygote mice was approximately 50% reduced as compared to that in wild-type mice. Under these conditions, a significant antinociception produced by subcutaneous (s.c.) injection of morphine (5 mg/kg) observed in wild-type mice was markedly reduced in opt heterozygote mice. These findings suggest that IP3 receptor-, especially type 1 IP3 receptor-mediated intracellular signaling pathway may be implicated in the expression of antinociceptive effect induced by morphine in mice.

Changes in G-protein activity mediated through the stimulation of dopamine and GABA(B) receptors in the mesolimbic dopaminergic system of morphine-sensitized mice

The behavioural sensitization has been recognized as the increased behavioural response and the undesirable long-lasting changes in brain functions after repeated administration of abuse drugs. We examined whether behavioural sensitization to hyperlocomotion induced by intermittent morphine treatment could result from any changes in dopamine and GABA(B) receptor functions to activate G-proteins in the brain rewarding system in mice. Intermittent morphine treatment results in the upregulation of dopamine receptor-regulated G-protein activation in the mouse limbic forebrain, whereas this treatment causes the downregulation of GABA(B) receptor function to activate G-protein in the mouse lower midbrain. In behavioural experiments, intermittent administration of morphine in combination with either a dopamine receptor antagonist haloperidol or a GABA(B) receptor agonist baclofen abolished the development of sensitization to morphine-induced hyperlocomotion. The present data provide evidence that these G-protein activation changes may lead to behavioural sensitization to morphine-induced hyperlocomotion in mice.

Prenatal and neonatal exposure to bisphenol-A enhances the central dopamine D1 receptor-mediated action in mice: enhancement of the methamphetamine-induced abuse state

Bisphenol-A (BPA), one of the most common environmental endocrine disrupters, has been extensively evaluated for toxicity in a variety of tests in rodents, including developmental and reproductive toxicity, and carcinogenicity. However, little is known about its action on the CNS. In this report, we show that prenatal and neonatal exposure to BPA in mice leads to the enhancement of the dopamine D1 receptor-dependent rewarding effect induced by a psychostimulant methamphetamine. Furthermore, this treatment with BPA markedly enhanced hyperlocomotion and its sensitization induced by methamphetamine, which reflects extensive abuse associated with sociological and psychiatric problems. We also demonstrated that chronic exposure to BPA produced an up-regulation of dopamine D1 receptor function to activate G-protein in the mouse limbic forebrain, which is thought to be a critical site for the expression of rewarding effects by abuse drugs. Additionally, chronic BPA exposure produced a significant increase in levels of the dopamine D1 receptor mRNA in the whole brain. In contrast, no change in protein levels of methamphetamine-targeted proteins, dopamine transporter or the type 2 vesicle monoamine transporter in the brain was observed by prenatal and neonatal exposure to BPA. The present data provide the first evidence that prenatal and neonatal exposure to BPA can potentiate the central dopamine D1 receptor-dependent neurotransmission, resulting in supersensitivity of methamphetamine-induced pharmacological actions related to psychological dependence on psychostimulants.

Molecular evidence for the functional role of dopamine D3 receptor in the morphine-induced rewarding effect and hyperlocomotion

The aim of the present study was to investigate the role of dopamine D(3) receptors in the rewarding effect and hyperlocomotion induced by a prototypical mu-opioid receptor agonist morphine using dopamine D(3) receptor knock-out mice. The mu-opioid receptor in the brain determined by the [tylosil-3,5-(3)H(N)]-[D-Ala(2),N-MePhe(4),Gly-ol(5)]enkephalin binding assay was not significantly changed by a deletion of the dopamine D(3) receptor gene. Furthermore, we found that no significant differences in G-protein activation by morphine in the limbic forebrain and lower midbrain were noted between the two genotypes. These results suggest that the function of the mu-opioid receptor itself was not affected by a deletion of the dopamine D(3) receptor gene. To ascertain the morphine-induced rewarding effect in both genotypes, the conditioned place preference paradigm was performed. Deletion of the dopamine D(3) receptor gene resulted in a remarkable enhancement of the morphine-induced rewarding effect. Furthermore, knock-out mice with deletions of the dopamine D(3) receptor revealed a dramatic potentiation of morphine-induced hyperlocomotion. Under these conditions, a loss of the dopamine D(3) receptor gene had no effect on the basal levels of dopamine and the increased dopamine turnover by morphine in the limbic forebrain. These findings provide further evidence that dopamine D(3) receptor contributes to the postsynaptically negative modulation of the mesolimbic dopaminergic pathway that is associated with the rewarding effect and hyperlocomotion through the stimulation of mu-opioid receptors induced by morphine in the mouse.

Up-regulation of the G(q/11alpha) protein and protein kinase C during the development of sensitization to morphine-induced hyperlocomotion

It has been recognized that protein kinase C (PKC) pathway is involved in the synaptic plasticity. The present study was then designed to examine the changes in G(q/11alpha) and G(betagamma) subunits and PKC activity on sensitization to the morphine-induced hyperlocomotion. Repeated subcutaneous administration of morphine every 72 h produced sensitization to the morphine-induced hyperlocomotion. In morphine-sensitized mice, the protein level of G(q/11alpha) subunit in the limbic forebrain including the nucleus accumbens, but not in the lower midbrain containing the ventral tegmental area, was markedly increased, whereas the levels of G(betagamma) subunit were not altered in either areas. Under these conditions, the levels of membrane-bound phosphorylated-PKC in the limbic forebrain was clearly up-regulated by intermittent morphine treatment. We also found the lack of changes in the level of the regulator of G protein signaling 4, which is a specific G(q/11alpha)-dependent GTPase activating protein, in the limbic forebrain obtained from morphine-sensitized mice. These results indicate that the up-regulation of membrane-bound PKC following intermittent morphine treatment results from the increase in levels of G(q/11alpha) protein. In order to investigate the direct involvement of PKC in the morphine-induced hyperlocomotion, the locomotion induced by acute morphine treatment in the presence or absence of a PKC inhibitor was measured. A specific PKC inhibitor Ro-32-0432 given intracerebroventricularly caused a dose-dependent inhibition of morphine-induced hyperlocomotion. These findings suggest that the up-regulation of G(q/11alpha)-dependent PKC activity in membranes of the limbic forebrain is implicated in the development of sensitization to morphine-induced hyperlocomotion in mice.

Assessment of regional early diastolic function using cine magnetic resonance imaging in patients with hypertrophic cardiomyopathy

In patients with hypertrophic cardiomyopathy (HCM), we conducted cine magnetic resonance imaging (MRI) studies in which our objectives were to quantify the regional early diastolic function of the left ventricle and to evaluate the relationship between regional diastolic function and hypertrophy. Short-axis images of the left ventricle were recorded by cine MRI in 8 control patients and 24 patients with HCM. The images were then divided into 10 blocks to evaluate regional early diastolic function. The regional wall-thickness-time curve, the radius-time curve, and their first-derivative curves were computed for each of the 10 blocks. There was no difference between the time-to-peak-radius-increasing ratio and the time-to-peak-wall-thickness-thinning ratio in the 10 blocks in the control patients. These 2 parameters in the patients with HCM were significantly longer than those in the control patients. There was also a significant linear correlation between the time-to-peak-wall-thickness-thinning ratio and regional wall thickness. Cine MRI was useful for evaluating regional early diastolic function, which is apparently related to regional hypertrophy, in patients with HCM.

Apical hypertrophy associated with rapid T wave inversion on the electrocardiogram

A 53-year-old man who had no chest pain and no family history of heart disease demonstrated a rapid T wave change on an electrocardiogram, from a positive T wave to a giant negative T wave, within 1 year. Echocardiography showed no left ventricular hypertrophy before or after the T wave change. Cine-magnetic resonance imaging revealed focal apical hypertrophy after the appearance of the giant negative T wave. Although T wave inversions sometimes develop within a short period in patients with hypertrophic cardiomyopathy, they are rare in a patient without hypertension or chest pain.

Early afterdepolarization abolished by potassium channel opener in a patient with idiopathic long QT syndrome

We describe a 17-year-old boy with idiopathic long QT syndrome and repeated syncopal episodes. Early afterdepolarization (EAD) in the monophasic action potential (MAP) was demonstrated in the posterior septum of the left ventricle. Injection of the potassium channel opener nicorandil decreased EAD and shortened MAP duration. The syncopal episodes due to ventricular fibrillation disappeared after administration of the potassium channel opener.

Effects of nipradilol on venous hemodynamics: evaluation with a Doppler blood flow method

Nipradilol is a newly synthesized beta-blocker which has a propranolol-like structure and contains a nitrate moiety. To examine the effect of nipradilol on venous blood flow, a single oral dose of nipradilol (6 mg) and propranolol (20 mg) was administered in the same 15 normal volunteers on separate days. Peak flow velocities, flow velocity integrals, and the diameter of the right brachiocephalic vein were measured before and 2 h after drug administration using Doppler echocardiography. These two beta-blockers significantly decreased systolic blood pressure to the same extent as they did heart rate. Nipradilol dilated the venous diameter by 8% and decreased peak flow velocity by 8% during systole and 9% during diastole. The flow velocity integral in one cardiac cycle also decreased significantly by 14%. Propranolol, however, failed to modify these parameters. These results suggest that nipradilol decreased venous return through its nitroglycerin-like direct vasodilating action.