Fasting and high-fat diet alter histone deacetylase expression in the medial hypothalamus.

Increasing attention is now being given to the epigenetic regulation of animal and human behaviors including the stress response and drug addiction. Epigenetic factors also influence feeding behavior and metabolic phenotypes, such as obesity and insulin sensitivity. In response to fasting and high-fat diets, the medial hypothalamus changes the expression of neuropeptides regulating feeding, metabolism, and reproductive behaviors.

Dopamine D5 receptor immunoreactivity is differentially distributed in GABAergic interneurons and pyramidal cells in the rat medial prefrontal cortex.

In the rodent neocortex, the dopamine D5 receptor (D5R) appears to be the predominant subtype of D1-like receptors that are generally considered to play important roles in cognitive functions subserved by the prefrontal cortex (PFC). In this study, to identify the precise localization of D5R in rat PFC, we used a receptor-specific antibody and observed the immunolabeled structures by light and confocal laser scanning microscopies. D5R immunolabeling was found in nearly all neurons, both excitatory and inhibitory neurons.

Synaptic characteristics between cortical cells in the rat prefrontal cortex and axon terminals from the ventral tegmental area that utilize different neurotransmitters.

Projections from the ventral tegmental area (VTA) have been demonstrated to terminate in the prefrontal cortex (PFC) and to be dopaminergic and/or gamma-aminobutyric acidergic (GABAergic), forming a neural circuit implicated in certain memory and cognitive processes. However, it has not been determined whether gamma-aminobutyric acid (GABA) and dopamine (DA) are localized in certain types of axon terminals from the VTA to the PFC. To determine the synaptic characteristics made by postsynaptic prefrontal cortical structures and mesoprefrontal fibers utilizing either GABA or DA, we performed a double-labeling method for electron microscopy, in which we combined peroxidase markers for anterograde tract-tracing with postembedding immunogold labeling for tyrosine hydroxylase, DA, and GABA in rats.

Immunolocalization of muscarinic receptor subtypes in the reticular thalamic nucleus of rats.

In this study, to identify the precise localization of the muscarinic receptor subtypes m2, m3 and m4 in the rostral part of the rat reticular thalamic nucleus (rRt), namely, the limbic sector, we used receptor-subtype-specific antibodies and characterized the immunolabeled structures by light, confocal laser scanning, and electron microscopies. The m2-immunolabeling was preferentially distributed in the distal dendrite region where cholinergic afferent fibers tend to terminate and in the peripheral region of somata, whereas the m3-immunolabeling was more preferentially distributed in a large part of somata and in proximal dendrite shafts than in the distal dendrite region. Dual-immunofluorescence experiments demonstrated that majority of rRt neurons with parvalbumin immunoreactivity contain both m2 and m3.

Thalamocortical projection from the ventral posteromedial nucleus sends its collaterals to layer I of the primary somatosensory cortex in rat.

Here we examined quantitatively axonal projections originating from the ventral posteromedial thalamic nucleus (VPM) to layer I of the primary somatosensory cortex (SI) by extracellular and intracellular injections of biocytin as an anterograde tracer. Following the extracellular injections, two types of VPM afferents with different arborization patterns in SI were observed. The type I extended vertically, forming dense plexus in layers IV and VI, and projected collaterals to layer I.

Synaptic relationships between axon terminals from the mediodorsal thalamic nucleus and gamma-aminobutyric acidergic cortical cells in the prelimbic cortex of the rat.

Although the reciprocal interconnections between the prefrontal cortex and the mediodorsal nucleus of the thalamus (MD) are well known, the involvement of inhibitory cortical interneurons in the neural circuit has not been fully defined. To address this issue, we conducted three combined neuroanatomical studies on the rat brain. First, the frequency and the spatial distribution of synapses made by reconstructed dendrites of nonpyramidal neurons were identified by impregnation of cortical cells with the Golgi method and identification of thalamocortical terminals by degeneration following thalamic lesions.

Microglial ecto-Ca(2+)-ATPase activity in a rat model of focal homologous blood clot embolic cerebral ischemia: an enzyme histochemical study.

Post-ischemic changes in ecto-Ca(2+)-ATPase activity in microglia and the infarcted tissue were studied in a rat model of focal embolic cerebral ischemia using an enzyme histochemical method. Ecto-Ca(2+)-ATPase activity was observed in whole brains in non-operated and sham-operated control animals. In addition, this enzyme activity was determined to be localized in ramified microglia.