Perinatal Exposure of Bisphenol A Differently Affects Dendritic Spines of Male and Female Grown-Up Adult Hippocampal Neurons.

Perinatal exposure to Bisphenol A (BPA) at a very low dose may modulate the development of synapses of the hippocampus during growth to adulthood. Here, we demonstrate that perinatal exposure to 30 μg BPA/kg per mother's body weight/day significantly altered the dendritic spines of the grownup rat hippocampus. The density of the spine was analyzed by imaging of Lucifer Yellow-injected CA1 glutamatergic neurons in adult hippocampal slices.

Prenatal bisphenol A exposure is associated with medial amygdala neuron hyperresponsiveness to predator odor in rats.

Perinatal exposure to bisphenol A (BPA) causes several alterations in brain function and behavior. In previous studies, we showed that prenatal treatment with low-level BPA impaired gender-specific behavior, enhanced depression-like behavior, and augmented behavioral responses to predator odor in rats. On this premise, we hypothesized that BPA-treated rats were more susceptible to predator odor stress.

The functional link between tail-pinch-induced food intake and emotionality and its possible role in stress coping in rats.

Tail pinch facilitates eating in rats. We investigated an unidentified link between tail-pinch-induced eating behavior and individual emotionality in male Sprague-Dawley rats. Anxiety-like behavior was assessed on the elevated plus maze (EPM) and in the open field test (OFT).

Water spray-induced grooming is negatively correlated with depressive behavior in the forced swimming test in rats.

Rodents show grooming, a typical self-care behavior, under stress and non-stress conditions. Previous studies revealed that grooming under stress conditions such as the open-field test (OFT) or the elevated plus-maze test (EPM) is associated with anxiety, but the roles of grooming under non-stress conditions are not well understood. Here, we examined spray-induced grooming as a model of grooming under a non-stress condition to investigate the relationship between this grooming and depression-like behavior in the forced swim test (FST) and tail suspension test, and we compared spray-induced grooming with OFT- and EPM-induced grooming.

Prenatal low-dose bisphenol A enhances behavioral responses induced by a predator odor.

Bisphenol A (BPA) is an environmental endocrine disrupter (EED). Previous studies by our group showed that pre- and postnatal administration of low-level BPA induced depression-like behavior in rats. In this study, we evaluated the effects of prenatal BPA on behavioral responses to a predator odor by using a novel cross-form apparatus consisting of 4 plastic chambers.

Development of a direct exposure system for studying the mechanisms of central neurotoxicity caused by volatile organic compounds.

Many volatile organic compounds (VOCs) used in work places are neurotoxic. However, it has been difficult to study the cellular mechanisms induced by a direct exposure to neurons because of their high volatility. The objective of this study was to establish a stable system for exposing brain slices to VOCs.

Brief neonatal handling alters sexually dimorphic behaviors in adult rats.

Several effects of neonatal handling on brain and behavior have been reported. We investigated the effects of neonatal handling on behaviors that have been shown to be sexually dimorphic in rats using an open-field test. "Gender differences" were observed in locomotor activity, exploratory behavior and grooming in the handled group.

Postnatal exposure to low-dose bisphenol A influences various emotional conditions.

Bisphenol A (BPA) is one of the 'environmental endocrine disrupters' (EEDs) released by plastics and resin known to interfere with hormonal responses. In this study, female Wistar rats were exposed to low-dose BPA (24 μg/kg/day) during 7 days after giving birth. The male and female offspring, exposed to the BPA through lactation, were evaluated using an open field test (OFT) at the age of six weeks, an elevated plus maze test (EPM) at seven weeks, and a forced swimming test (FST) at nine weeks.

Multisensory interaction mediates the social transmission of avoidance in rats: dissociation from social transmission of fear.

Social interaction enables animals to transmit various types of sensory information that can modulate learned avoidance behavior and fear responses, which are important to survival. We previously reported that, under a passive avoidance paradigm, avoidance behavior is facilitated when a rat observes another rat (demonstrator) receiving a shock when performing a specific behavior. However, the sensory mechanisms underlying this 'social facilitation of avoidance' are not well understood.

Penicillin-induced epileptiform activity elevates focal brain temperature in anesthetized rats.

To elucidate a relationship between changes in focal brain temperature and severity of abnormal brain activity, epileptiform discharges and behavioral seizures were induced by Penicillin G in anesthetized rats, and focal brain-temperature was measured. Penicillin G was injected into the right primary sensorimotor cortex (400IU/μl). After the injection, epileptiform discharges induced a temperature increase gradually by 0.

Neurotoxin A2NTX Blocks Fast Inhibitory and Excitatory Transmitter Release From Presynaptic Terminals.

Our recent study showed a possibility that newly developed A2 type botulinum toxin (A2NTX) inhibits both spontaneous and evoked transmitter release from inhibitory (glycinergic or GABAergic) and excitatory (glutamatergic) nerve terminals using rat spinal sacral dorsal commissural nucleus neurons. In the present study, to determine the modulatory effect of A2NTX on glycinergic and glutamatergic release probabilities, we tested the effects of A2NTX on a single inhibitory or excitatory nerve ending adherent to a dissociated neuron that was activated by paired-pulse stimuli by using the focal electrical stimulation technique. The results of the present paired-pulse experiments showed clearly that A2NTX enhanced paired-pulse facilitation of evoked glycinergic inhibitory postsynaptic currents and glutamatergic excitatory postsynaptic currents and increased the failure rate (Rf) of the first postsynaptic currents (P) and both the responses.

Neurotoxin A2NTX blocks fast inhibitory and excitatory transmitter release from presynaptic terminals.

Our recent study showed a possibility that newly developed A2 type botulinum toxin (A2NTX) inhibits both spontaneous and evoked transmitter release from inhibitory (glycinergic or GABAergic) and excitatory (glutamatergic) nerve terminals using rat spinal sacral dorsal commissural nucleus neurons. In the present study, to determine the modulatory effect of A2NTX on glycinergic and glutamatergic release probabilities, we tested the effects of A2NTX on a single inhibitory or excitatory nerve ending adherent to a dissociated neuron that was activated by paired-pulse stimuli by using the focal electrical stimulation technique. The results of the present paired-pulse experiments showed clearly that A2NTX enhanced paired-pulse facilitation of evoked glycinergic inhibitory postsynaptic currents and glutamatergic excitatory postsynaptic currents and increased the failure rate (Rf) of the first postsynaptic currents (P(1)) and both the responses.

Lesions of the medial prefrontal cortex enhance social modulation of avoidance.

Our previous study showed that social interactions induce inhibitory and facilitatory modulations of avoidance behavior under both safe and dangerous situations in rats. To understand the neural mechanisms for these phenomena, we investigated the effects of bilateral lesions of the medial prefrontal cortex (mPFC) on the social modulation of avoidance behavior. We found that the lesions did not impair but actually augmented both social inhibition and facilitation of avoidance.

Ca2+/calmodulin-dependent protein kinase II and protein kinase C activities mediate extracellular glucose-regulated hippocampal synaptic efficacy.

To define how extracellular glucose levels affect synaptic efficacy and long-term potentiation (LTP), we evaluated electrophysiological and neurochemical properties in hippocampal CA1 regions following alterations in glucose levels in the ACSF. In rat hippocampal slices prepared in ACSF with 3.5mM glucose, fEPSPs generated by Schaffer collateral/commissural stimulation markedly increased when ACSF glucose levels were increased from 3.

Prandial increases of leptin and orexin in the brain modulate spatial learning and memory.

Leptin is well known to be involved in the inhibition of feeding, hermogenesis, reproduction and neuroendocrine functions through its actions on the rodents hypothalamic receptors. Leptin facilitated the presynaptic transmitter release and postsynaptic sensitivity to the transmitters in the hippocampal CA1 neurons. Thus long-term potentiation (LTP) and the phosphorylation of Ca2+/calmodulin protein kinase II (CaMK II) were facilitated in the CA1 neurons.

Social transmission of avoidance behavior under situational change in learned and unlearned rats.

Background: Rats receive information from other conspecifics by observation or other types of social interaction. Such social interaction may contribute to the effective adaptation to changes of environment such as situational switching. Learning to avoid dangerous places or objects rapidly occurs with even a single conditioning session, and the conditioned memory tends to be sustained over long periods.

Prandial increase of leptin in the brain activates spatial learning and memory.

Leptin is well known to be involved in the control of feeding, thermogenesis, reproduction and neuroendocrine functions through its actions on the rodents hypothalamic receptors. Leptin facilitated the presynaptic transmitter release and postsynaptic sensitivity to the transmitters in the hippocampal CA1 neurons. Thus long-term potentiation (LTP) and the phosphorylation of Ca(2+)/calmodulin protein kinase II (CaMKII) were facilitated in the CA1 neurons.

Dynamical properties of the two-process model for sleep-wake cycles in infantile autism.

The two-process model is a scheme for the timing of sleep that consists of homeostatic (Process S) and circadian (Process C) variables. The two-process model exhibits abnormal sleep patterns such as internal desynchronization or sleep fragmentation. Early infants with autism often experience sleep difficulties.

Categorization of biologically significant objects, food and gender, in rhesus monkeys. I. Behavioral study.

Macaque monkeys have a highly evolved visual system comparable to that of humans. One of the important visual functions is performing discriminations among biologically significant objects such as food or heterosexual partners. In the present study, we examined whether rhesus monkeys could categorize two-dimensional images related to food or gender using a visual discrimination task.

Role of substantia innominata in cerebral blood flow autoregulation.

Ascending projections from the substantia innominata (SI) may have an important role in the regulation of cerebral blood flow (CBF). However, several reports have suggested that unilateral lesion of the SI does not affect CBF autoregulation. On the other hand, it is also reported that several cortical and subcortical functions may be regulated not only by ipsilateral SI, but also by contralateral SI.

Prenatal exposure to bisphenol A impairs sexual differentiation of exploratory behavior and increases depression-like behavior in rats.

Perinatal exposure to bisphenol A (BPA, 0.1 and 1 ppm in drinking water applied to mother rats for 6 weeks) has been shown to impair the sexual differentiation in exploratory behavior, but the exact critical period of this disrupting effect is still unknown. In this study, we examined the effects of prenatal exposure to BPA (0.

Distribution of tributyltin, dibutyltin and monobutyltin in the liver, brain and fat of rats: two-generation toxicity study of tributyltin chloride.

The distribution of tributyltin (TBT) and its metabolites, dibutyltin (DBT) and monobutyltin (MBT), was examined in the liver, brain and fat tissues in a two-generation reproductive toxicity study of tributyltin chloride (TBTCl) in rats using dietary supplementation at concentrations of 5, 25 and 125 ppm. In the liver, irrespective of TBTCl dietary concentration, gender or generation, the highest concentration of metabolite was consistently MBT, followed by DBT, and then TBT. In contrast, TBT was consistently present at the highest concentration in the brain, nearly always followed by DBT and MBT.

Physiological significance of 2-buten-4-olide (2-B4O), an endogenous satiety substance increased in the fasted state.

A sugar acid, 2-B4O, has been found to increase from 3.5 to 13 microM in rat serum at 36 h after food deprivation. Injections of 2-B4O (2.