High Ethanol and Acetaldehyde Inhibit Glutamatergic Transmission in the Hippocampus of Aldh2-Knockout and C57BL/6N Mice: an In Vivo and Ex Vivo Analysis.

We aimed to investigate whether ethanol (EtOH) and acetaldehyde (AcH) can affect glutamate and its receptors GluN1 and GluA1 in the hippocampus of Aldh2-knockout (Aldh2-KO) and C57BL/6N (wild-type (WT)) mice. To do this, we first examined the effect of local administration of EtOH (100 mM, 200 mM, and 500 mM) and AcH (100 µM, 200 µM, and 500 µM) on extracellular glutamate levels in freely moving mice. Retrodialysis of 200 mM and 500 mM EtOH into the hippocampus of WT and Aldh2-KO mice produced significant decreases in extracellular glutamate levels (p < 0.05). A dose of 500 mM EtOH induced a greater decrease in Aldh2-KO mice (p < 0.05) than in WT mice, indicating the action of AcH. Similarly, perfusion of 200 µM and 500 µM AcH decreased glutamate in Aldh2-KO mice (p < 0.05), but this decrease was not seen in WT mice at any AcH dose. Second, we tested whether the EtOH- and AcH-induced decrease in glutamate was associated with decreases in GluN1 and GluA1 expression, as measured by real-time PCR and Western blot. We found a significant decrease in GluN1 (p < 0.05) and GluA1 (p < 0.05) subunits after a high dose of EtOH (4.0 g/kg) and AcH (200 mg/kg) in WT mice. However, a 2.0 g/kg dose of EtOH did not produce a consistent decrease in GluN1 or GluA1 between messenger RNA and protein. In Aldh2-KO mice, all three doses of EtOH (1.0 g/kg, 2.0 g/kg, and 4.0 g/kg) and AcH (50 mg/kg, 100 mg/kg, and 200 mg/kg) decreased GluN1 expression (p < 0.05), while moderate-to-high doses of EtOH (2.0 g/kg and 4.0 g/kg) and AcH (100 mg/kg and 200 mg/kg) decreased GluA1 expression (p < 0.05). Together, these in vivo and ex vivo data suggest that EtOH and AcH decrease extracellular glutamate in the hippocampus of mice with a concomitant decrease in GluN1 and GluA1 subunits, but these effects require relatively high concentrations and may, therefore, explain the consequences of EtOH intoxication.

A unique pattern of bisphenol a effects on nerve growth factor gene expression in embryonic mouse hypothalamic cell line N-44.

We investigated the toxicity of bisphenol A (BPA) by determining the gene expression of nerve growth factor (Ngf in the embryonic mouse cell line mHypoE-N44 derived from the hypothalamus exposed to BPA dose range between 0.02 and 200 µmol L-1 for 3 h. Ngf mRNA levels decreased in a dose-dependent manner, with significant reductions observed in the 2 to 50 µmol L-1 BPA treatment groups compared to controls. However, at 100 to 200 µmol L-1 the NgfmRNA gradually increased and was significantly higher than control, while the expression of the apoptosis-related genes Caspase 3 and transformation-related protein 73 decreased significantly. These results suggest that in an embryonic hypothalamic cell line the higher doses of BPA induce a unique pattern of Ngf gene expression and that BPA has the potential to suppress apoptosis essential for early-stage brain development.

Gene expression of epigenetic regulatory factors related to primary silencing mechanism is less susceptible to lower doses of bisphenol A in embryonic hypothalamic cells.

DNA methyltransferases (DNMTs) are associated with epigenetic regulation of gene expression, and methyl-CpG binding protein 2 (MECP2) acts as a long-range regulator of methylated genes. We evaluated the effects of bisphenol A (BPA) on embryonic mouse hypothalamic cells, with particular emphasis on the gene expression of Dnmts (Dnmt1, Dnmt3a, and Dnmt3b) and Mecp2 isoforms. In a dose-dependent (0.02-200 µM BPA) 3-hr experiment, real-time reverse transcription polymerase chain reaction revealed that gene expression of both Dnmts and Mecp2_e2 was affected at 200 µM and that of Mecp2_e1 was affected at > 20 µM. These results suggest that gene expression of Dnmts and Mecp2 are less susceptible to lower doses of BPA in developing hypothalamic cells. However, as BPA concentration increases, this agent has the potential to alter gene expression of key players that provide stability and flexibility of epigenetic gene regulation, which could disrupt the normal development of hypothalamic functions.

Effects of systemic nicotine, alcohol or their combination on cholinergic markers in the frontal cortex and hippocampus of rat.

Acute alcohol (Alc) intoxication has been shown to decrease choline acetyltransferase (ChAT) in the rat brain. The present study extends that finding by examining the effects of nicotine (Nic), Alc, and their combination on ChAT and acetylcholinesterase (AChE) in the frontal cortex and hippocampus of rat. The samples were collected at 30 and 120 min after intraperitoneal administration of saline (0.9%, control), Nic (1 mg/kg), Alc (1 g/kg), and Nic + Alc and analyzed by RT-PCR, Western blot and colorimetry. Alc alone considerably reduced ChAT mRNA expression, whereas Nic alone decreased AChE mRNA expression. In contrast, Nic + Alc exposure had resulted in no significant change in the parameters. These findings are consistent with the results of the Western blot and AChE activity analysis. The results, therefore, indicate that Nic and Alc alone may interact with the central cholinergic system. This interactive effect may contribute to a frequent association of tobacco and Alc consumption.

Cholinergic alterations following alcohol exposure in the frontal cortex of Aldh2-deficient mice models.

We investigated the effects of alcohol (EtOH) and acetaldehyde (ACe) on choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) in the frontal cortex of Aldh2-/- (KO) mice. KO mice were used as models of Aldh2-deficient humans to examine ACe effects. Brain samples were analyzed at 40 and 120 min after 2- and 4-g/kg intraperitoneal EtOH administration by RT-PCR and Western blot. Wild-type (WT) mice exhibited a remarkable decrease in ChAT and AChE mRNA expression at both time points only after 4-g/kg EtOH treatment compared with the naive control, whereas KO mice showed a considerable reduction in cholinergic markers after 2- and 4-g/kg EtOH treatment. The 4-g/kg EtOH-induced decrease in ChAT and AChE RNA expression at both time points was significantly greater than that in obtained with the administration of 2-g/kg at 40 min in WT mice. KO mice showed a significant difference in ChAT mRNA at 40 min between the EtOH groups. The findings regarding the ChAT mRNA levels are consistent with the results of Western blot in both types of mice, with some exceptions. EtOH-induced ChAT and AChE expression in KO mice was significantly lower than that in WT mice. This genotype effect occurred mostly at 40 min after EtOH dosing. Only ACe was quantified in the brains of KO mice, whereas EtOH was detected in both types of mice in vivo. These results suggest that EtOH and ACe combined or high EtOH alone alters cholinergic markers expression via changes in presynaptic and postsynaptic processes in the mice frontal cortex, thus indicating that central cholinergic neurons may be sensitive to EtOH and ACe.

c-Fos expression in the periaqueductal gray is induced by electroacupuncture in the rat, with possible reference to GABAergic neurons.

Electroacupuncture (EA) delivered to the acupoint (AP) called Zusanli (ST36) was administered on the bilateral hindlimb. This experiment resulted in strong expression of c-Fos immunoreactivity in the ventrolateral to lateral subdivision throughout the periaqueductal gray (PAG) compared to the non-AP and sham cases. On the other hand, it was of particular interest in the experiment of the AP that strong expression of gamma aminobutylic acid (GABA) frequently showed similar pattern of distribution to that of c-Fos in the PAG. This overlapped pattern of distribution, demonstrated in the present study, suggests that the PAG neurons activated by EA at the AP might play an important role in the descending pain control system involving the GABA since the PAG has special reference to the dorsal horn of the spinal cord and function of pain control.

Toluene diisocyanate exposure induces laryngo-tracheal eosinophilia, which can be ameliorated by supplementation with antioxidant vitamins in guinea pigs.

OBJECTIVE: Toluene diisocyanate (TDI)-induced asthma is a common cause of occupational lung disease. In addition, a sore throat is one of the complaints of TDI-exposed workers. The aim of the present study was to determine whether TDI exposure induces laryngeal and/or tracheal lesions in experimental animals. MATERIAL AND METHODS: Guinea pigs underwent naris application of TDI three times, and their respiratory tracts were then examined using light and electron microscopy. Some animals simultaneously received vitamins C and E. which function as antioxidant agents. RESULTS: When TDI-treated animals showed the clinical sign of labored breathing, many eosinophils had appeared in the lamina propria and mucosa of both the larynx and trachea, which finally infiltrated the tract lumen through the ruptured epithelium. Laryngo-tracheal inflammation was more severe than that observed in the lungs. However, supplementation with antioxidant vitamins in TDI-treated animals ameliorated the respiratory eosinophilia. CONCLUSION: Naris application of TDI induced laryngotracheitis. which was significantly suppressed by the antioxidant vitamins, This implies a preventive effect of the vitamins on this occupational disease.