Excitatory synchronization of rat hippocampal interneurons during network activation .

Introduction: Hippocampal interneurons (INs) are known to synchronize their electrical activity mechanisms, which are poorly defined due to immense complexity of neural tissue but seem to depend on local cell interactions and intensity of network activity.

Methods: Here, synchronization of INs was studied using paired patch-clamp recordings in a simplified culture model with intact glutamate transmission. The level of network activity was moderately elevated by field electric stimulation, which is probably an analogue of afferent processing .

Integration of energy homeostasis and stress by parvocellular neurons in rat hypothalamic paraventricular nucleus.

Key Points: Central regulation of energy homeostasis and stress are believed to be reciprocally regulated, i.e. excessive food intake suppresses, while prolonged hunger exacerbates, stress responses in vivo.

Astrocytes and presynaptic plasticity in the striatum: Evidence and unanswered questions.

One of the main functions of astrocytes is to ensure glutamate homeostasis by glutamate uptake and glutamine synthesis. However, during the past ten years it has become clear that astrocytes may also induce changes in synaptic glutamate release when respective pathways must cope with the consequences of brain damage or other alterations in their functional requirements. The loss of glutamatergic synapses in Parkinson's and Huntington's disease is likely to associate with a continuous redistribution of presynaptic activity within the pool of surviving synapses, and astrocytes may have a role in the maintenance of independent control at individual glutamate release sites.

Passageway: A Novel Approach to Success of Conditional Release - Principles and Constructs of the Model Residential Program for the Forensic Mentally III Patient.

With the advent of psychotropic medications and with the deinstitutionalization of psychiatry starting in 1968, patients were prematurely discharged from forensic state hospitals. Due to lack of resources, psychiatric forensic patients ended up in the correctional system or homeless with the reduction of psychiatric beds in forensic and civil state hospitals. Lacking proper training and medication management, the recidivism rate of this population was close to 10% for rearrest and about 35% for revocation of conditional release (CR; Manguno-Mire et al.

Cell type-specific postsynaptic effects of neuropeptide Y in substantia gelatinosa neurons of the rat spinal cord.

Cellular mechanisms of antinociceptive action of neuropeptide Y were investigated in substantia gelatinosa (SG) neurons in rat spinal cord slices. Somatic and synaptic effects of NPY were compared in two subpopulations of cells with different firing patterns, tonic (TFNs), and delayed firing (DFNs) neurons. For the study, TFNs were selected on morphological basis: they had appearance of central and radial but not islet cells, and are likely excitatory interneurons in dorsal horn networks.

Glucosensing in parvocellular neurons of the rat hypothalamic paraventricular nucleus.

Specialized hypothalamic neurons responding to rising extracellular glucose via increases or decreases in their electrical activity [glucose-excited (GE) and glucose-inhibited (GI) cells, respectively] have been reported in the hypothalamic arcuate, ventromedial and lateral nuclei. The hypothalamic paraventricular nucleus (PVN) is an important neurosecretory and preautonomic output nucleus. We tested whether parvocellular PVN neurons also possess glucosensing properties, using patch-clamp recording and immunocytochemistry.

A-type K+ current dominates somatic excitability of delayed firing neurons in rat substantia gelatinosa.

Substantia gelatinosa neurons display three main types of intrinsic firing behavior: tonic, adapting, and delayed onset. Here, voltage-gated currents expressed by delayed firing neurons were studied in nucleated patches obtained in spinal cord slices of 3-5 weeks-old rats. Inward Na+ current was negligible under these conditions and was usually occluded by superposition of much larger outward currents.

Electrically silent neurons in the substantia gelatinosa of the rat spinal cord.

Substantia gelatinosa (SG) neurons are usually categorized on three main types: tonic, adapting and delayed firing (DFNs), based on characteristic firing response evoked by sustained stimulation. Here, the existence of electrically silent neurons (ESNs, 9.3%) is reported by using patch-clamp recording and confocal microscopy in spinal cord slices from 3-5 weeks-old rats.

[Morphophysiologic properties of delayed firing neurons in substantia gelatinosa of the rat spinal cord.

Substantia gelatinosa (SG) neurons of the spinal cord are highly heterogeneous in their morphologic and physiologic properties. Based on characteristic firing response evoked by sustained depolarization, neurons can be categorized on three main types: tonic, adapting and delayed firing (DFNs). Here, properties of DFNs in spinal cord slices from 3-5 weeks-old rats were studied with the use of patch-clamp recording and confocal microscopy.

Morphophysiologic properties of islet cells in substantia gelatinosa of the rat spinal cord.

Substantia gelatinosa (SG) neurons of the spinal cord are highly heterogeneous in their morphophysiologic properties and could be categorized on several subtypes. Here the properties of islet cells in rat SG (approximately 11%) are described with the use of confocal microscopy and patch-clamp recording. The cells had significantly longer and thicker dendritic trees among all other neurons.

Developmental switch in neuropeptide Y and melanocortin effects in the paraventricular nucleus of the hypothalamus.

Homeostatic regulation of energy balance in rodents changes dramatically during the first 3 postnatal weeks. Neuropeptide Y (NPY) and melanocortin neurons in the arcuate nucleus, a primary energy homeostatic center in adults, do not fully innervate the paraventricular nucleus (PVN) until the third postnatal week. We have identified two classes of PVN neurons responsive to these neuropeptides, tonically firing neurosecretory (NS) and burst-firing preautonomic (PA) cells.

Psychiatric conditions in cosmetic surgery patients.

Beauty is important. As psychiatrists, we see the interface of beauty with mental health, self-esteem, and mental illness. As physicians who enhance cosmetic appearance, you encounter a broad spectrum of patients ranging from those with a healthy pursuit of enhanced appearance to those whose behavior is extremely maladaptive.

RNA editing produces glycine receptor alpha3(P185L), resulting in high agonist potency.

The function of supramedullary glycine receptors (GlyRs) is still unclear. Using Wistar rat collicular slices, we demonstrate GlyR-mediated inhibition of spike discharge elicited by low glycine (10 microM). Searching for the molecular basis of this phenomenon, we identified a new GlyR isoform.

Selective postsynaptic inhibition of tonic-firing neurons in substantia gelatinosa by mu-opioid agonist.

Background: Spinal substantia gelatinosa (SG) is a site of action of administered and endogenous opioid agonists and is an important element in the system of antinociception. However, little is known about the types of neurons serving as specific postsynaptic targets for opioid action within the SG. To study the spinal mechanisms of opioidergic analgesia, the authors compared the action of mu-opioid agonist [D-Ala, N-Me-Phe, Gly-ol]-enkephalin (DAMGO) on SG neurons with different intrinsic firing properties.

Mechanism of spike frequency adaptation in substantia gelatinosa neurones of rat.

Using tight-seal recordings from rat spinal cord slices, intracellular labelling and computer simulation, we analysed the mechanisms of spike frequency adaptation in substantia gelatinosa (SG) neurones. Adapting-firing neurones (AFNs) generated short bursts of spikes during sustained depolarization and were mostly found in lateral SG. The firing pattern and the shape of single spikes did not change after substitution of Ca2+ with Co2+, Mg2+ or Cd2+ indicating that Ca2+-dependent conductances do not contribute to adapting firing.

Ionic basis of tonic firing in spinal substantia gelatinosa neurons of rat.

Ionic conductances underlying excitability in tonically firing neurons (TFNs) from substantia gelatinosa (SG) were studied by the patch-clamp method in rat spinal cord slices. Ca(2+)-dependent K(+) (K(CA)) conductance sensitive to apamin was found to prolong the interspike intervals and stabilize firing evoked by a sustained membrane depolarization. Suppression of Ca(2+) and K(CA) currents, however, did not abolish the basic pattern of tonic firing, indicating that it was generated by voltage-gated Na(+) and K(+) currents.

Chronic treatment with ionotropic glutamate receptor antagonist kynurenate affects GABAergic synaptic transmission in rat hippocampal cell cultures.

It is well documented that prolonged treatment with antagonists of ionotropic glutamate receptors activates a number of homeostatic mechanisms including alteration of glutamatergic transmission. We studied whether this treatment can also affect GABAergic transmission. Using whole-cell voltage clamp recording and local extracellular stimulation we investigated evoked inhibitory postsynaptic currents (IPSCs) in cultured rat hippocampal neurons grown in the presence of ionotropic glutamate receptor antagonist kynurenate (1 mM) and in control conditions.

Time evolution of Lyman-alpha fine-structure components for Al XIII.

We present a comparison of measured and theoretically modeled Lyman-alpha intensity ratios of hydrogenlike Al XIII impurity ions in a deuterium base plasma in the COMPASS-D tokamak. The time evolution of the intensity ratios is computed from a collisional-radiative model using measured plasma parameters and compared with line-of-sight integral values measured using a high-resolution crystal spectrometer. The variations in the modeled values follow the experimental data in the case of the L-mode plasma, taking into account variations in the electron parameters during the discharges.

Post-tetanic depression of GABAergic synaptic transmission in rat hippocampal cell cultures.

The effect of tetanic stimulation (30 Hz, 4 s) on evoked GABAergic inhibitory postsynaptic currents (IPSCs) was studied in cell cultures of dissociated hippocampal neurons with established synaptic connections. It was found that tetanic stimulation elicited post-tetanic depression (PTD) of the evoked IPSCs with a duration of more than 50 s in about 60% of the connections tested; post-tetanic potentiation was induced in 25% of the connections. We propose that the opposite effects of tetanization on IPSC amplitude are due to differences in the type of the interneuron that was tetanized.

Postsynaptic mechanism may contribute to inhibitory acetylcholine effect on GABAergic synaptic transmission in hippocampal cell cultures.

The effect of acetylcholine (ACh) on evoked GABAergic inhibitory postsynaptic currents (IPSCs) was studied in cell cultures of dissociated hippocampal neurons with established synaptic connections. Spontaneous IPSCs and IPSCs evoked by extracellular stimulation of a single presynaptic neuron were recorded. ACh inhibited the evoked IPSCs in most of the connections, although facilitation was also observed.

Rat hippocampal neurons maintain their own GABAergic synaptic transmission in culture.

The whole-cell patch-clamp technique was used to record monosynaptic inhibitory postsynaptic currents (IPSCs) from pairs of hippocampal neurons cultured for 2-3 weeks. The application of fresh physiological solution for 2-3 min reversibly reduced the amplitude of evoked GABAergic IPSCs to 72.5% of control value.

In vitro development of vertebrate central synapses.

This article deals with basic determinants of synaptic efficacy during development of glutamatergic and GABAergic synaptic transmission: location and number of release sites, release probability and single cell-activated (unitary) conductances. We hypothesize that both types of neuronal connections differ in major aspects of synaptogenesis. Disregarding the fact that various test models and cell types could render diverging results, it can be observed that glutamatergic terminals display a preference for dendrites, whereas GABAergic terminals select soma locations at initial stages of development.

Development of spontaneous synaptic activity in culture of the chick spinal cord neurons.

Spontaneous postsynaptic currents in chick spinal cord neurons cultured for up to three weeks were recorded by using standard whole-cell patch-clamp techniques. Beginning with approximately the 7th to 14th day in vitro, giant postsynaptic currents, mediated presumably by glycine, were single synaptic events (inhibitory postsynaptic currents). After the 14th day in vitro excitatory postsynaptic currents appeared.

Glycine conductance changes in chick spinal cord neurons developing in culture.

Whole-cell glycine-activated currents were investigated in chick spinal cord neurons cultivated for up to three weeks. Based on the morphological and electrophysiological characteristics of neurons, two different types of nerve cells were distinguished during the first few days in culture. The first type consisted of "mature" nerve cells which appear to be motoneurons.