Persistent α1-adrenergic receptor function in the nucleus locus coeruleus causes hyperexcitability in AD/HD model rats.

Spontaneously hypertensive rats (SHR) are widely used as a model of attention deficit hyperactivity disorder (ADHD) as their ADHD-like behaviors are restored by methylphenidate. However, a postnatal neural development in SHR is unknown. We performed whole cell patch clamp recordings from locus coeruleus (LC) neurons in neonatal [postnatal day (P) 3-5], juvenile (P21-28), and adult (P 49-56) SHR and age-matched Wistar rats to evaluate α1- and α2-adrenergic receptor (ARs) activities at each developmental period.

Edaravone attenuates impairment of synaptic plasticity in granule cell layer of the dentate gyrus following traumatic brain injury.

Effects of edaravone, a free radical scavenger, on post-traumatic impairment of long-term potentiation (LTP) were examined in granule cell layers of the dentate gyrus (DG) in vitro. Field EPSPs (fEPSPs) evoked by stimulation of the perforant path (PP) were recorded extracellularly in the DG one week after a moderate impact applied by a fluid percussion injury (FPI) device. High frequency stimulation (HFS) of the PP caused LTP of the fEPSP-slope in slices from naïve and sham-operated rats, however, the LTP was strongly depressed in slices from FPI rats.

Methylphenidate enhances inhibitory synaptic transmission by increasing the content of norepinephrine in the locus coeruleus of juvenile rats.

The present study examined the effect of methylphenidate (MPH), a psychostimulant, on nor-adrenergic transmission in the locus coeruleus (LC) of juvenile rats. Intracellular recordings showed that MPH (>3 µM) produced a hyperpolarizing response associated with a decrease in the rate of spontaneously firing action potentials. MPH (1 µM) enhanced the amplitude of the inhibitory postsynaptic potential (IPSP) mediated by norepinephrine (NE), but did not change the excitatory postsynaptic potential (EPSP) mediated by excitatory amino acids.

Expression of the TRPM8-immunoreactivity in dorsal root ganglion neurons innervating the rat urinary bladder.

The neurochemical phenotypes of the transient receptor potential melastatin-8 (TRPM8)-immunoreactive afferent neurons innervating the rat urinary bladder were examined by using a highly sensitive tyramide signal amplification method, combined with wheat-germ agglutinin-horseradish peroxidase (WGA-HRP) retrograde tracing. TRPM8-immunoreactivity was detected in a small proportion of the WGA-HRP-labeled bladder afferent neurons in the dorsal root ganglia of the Th13-L1 (1.14%) and the L6-S1 (1.

Mild hypothermia prevents post-traumatic hyperactivity of excitatory synapses in rat hippocampal CA1 pyramidal neurons.

The present experiment examined the effect of mild hypothermia (35 degrees C) on the post-traumatic hyperactivity of rat hippocampal CA1 neurons in horizontal brain slices. One week after fluid percussion injury (FPI), the optical response evoked by stimulation of the Schaffer collaterals increased in amplitude and propagation area in hippocampal CA1 slices. FPI did not alter the fast optical response that reflected the action potential of the Schaffer collaterals but enhanced the slow component that reflected the excitatory postsynaptic response.

Dopamine presynaptically depresses fast inhibitory synaptic transmission via D4 receptor-protein kinase A pathway in the rat dorsolateral septal nucleus.

The lateral septal nucleus receives a diffuse dopaminergic input originating from the ventral tegmental area of the brain stem. We examined whether dopamine (DA) modulates synaptic transmission in the slice preparation of the rat dorsolateral septal nucleus (DLSN). Bath application (10-15 min) of DA (30 muM) markedly depressed the amplitude of fast and slow inhibitory postsynaptic potentials (IPSPs) in DLSN neurons, while it produced only a minor depression of the amplitude of excitatory postsynaptic potentials (EPSPs) obtained in the presence of bicuculline.

Facilitation of glutamatergic synaptic transmission in hippocampal CA1 area of rats with traumatic brain injury.

We investigated the effects of traumatic brain injury (TBI) on the glutamatergic synaptic transmission in the hippocampal CA1 area. A moderate impact (3.8-4.

Effects of emodin on synaptic transmission in rat hippocampal CA1 pyramidal neurons in vitro.

Rhubarb extracts provide neuroprotection after brain injury, but the mechanism of this protective effect is not known. The present study tests the hypothesis that rhubarb extracts interfere with the release of glutamate by brain neurons and, therefore, reduce glutamate excitotoxicity. To this end, the effects of emodin, an anthraquinone derivative extracted from Rheum tanguticum Maxim.

Effects and wavelet spectral entropy analysis of rhubarb extracts rhein on synaptic transmission in rat hippocampal ca1 area in vitro.

Background: 5-dihydroxyanthraquinone-2-carboxylic acid (rhein) inhibits oxidoreduction induced by reducing nicotingamide adenine dinucleotide in the mitochondria and reducing reactive oxygen species, it also suppresses lipid peroxidation in rat brain homogenates. This study was to assess the effects of anthraquinone derivatives, rhein on synaptic transmission in the rat hippocampal CA1 pyramidal cell layer by intracellular recording.

Methods: The excitatory postsynaptic potential (EPSP) evoked by stimulation of the Schaffer collaterals in the presence of bicuculline (15 micromol/L) was depressed by application of rhein (0.

Effects of milnacipran on the inhibitory postsynaptic potential in neurons of the rat locus coeruleus.

Effects of milnacipran (MIL), a serotonin and noradrenaline reuptake inhibitor (SNRI), on synaptic transmission were examined in the rat locus coeruleus (LC). Bath-application of MIL produced a hyperpolarization associated with a decrease in input resistance of LC neurons. The MIL-induced hyperpolarization reversed polarity near the equilibrium potential of K+.

[Effects of milnacipran on neuronal excitability and synaptic transmission in neurons of the rat locus coeruleus].

Effects of milnacipran (MIL), a selective serotonin and noradrenaline (NA) reuptake inhibitor, on the neuronal excitability and synaptic transmission in the rat locus coeruleus (LC) were examined by intracellular and whole-cell patch-clamp recording techniques. We compared MIL and methylphenidate (MPH), a selective NA and dopamine reuptake inhibitor, as a therapeutic agent for attention deficit/hyperactivity disorder. Application of MPH (1-100 microM) and MIL (1-100 microM) to artificial cerebrospinal fluid (ACSF) produced a hyperpolarizing response in LC neurons in a concentration-dependent manner.

Mechanical unloading improves intracellular Ca2+ regulation in rats with doxorubicin-induced cardiomyopathy.

Objectives: We sought to assess whether mechanical unloading has beneficial effects on cardiomyocytes from doxorubicin-induced cardiomyopathy in rats.

Background: Mechanical unloading by a left ventricular assist device (LVAD) improves the cardiac function of terminal heart failure in humans. However, previous animal studies have failed to demonstrate beneficial effects of mechanical unloading in the myocardium.

5-Hydroxytryptamine 1B receptors mediate presynaptic inhibition of monosynaptic IPSC in the rat dorsolateral septal nucleus.

Effects of 5-hydroxytryptamine (5-HT) on inhibitory synaptic transmission in the rat dorsolateral septal nucleus (DLSN) were examined by conventional intracellular and voltage-clamp recording methods. 5-HT (1-30 microM) depressed the monosynaptic fast IPSC evoked by local stimulation of the DLSN in the presence of DNQX, AP5 and CGP 55845A. CP 93129, a selective 5-HT1B receptor agonist, depressed the fast IPSC.

L-arginine enhances heat-induced depression of neuronal activity in the rat hippocampal CA1 area.

Effects of L-arginine on the heat-induced depression of the neuronal activity in the hippocampal CA1 area were investigated using optical recording techniques. An increase in the temperature of hippocampal neurons from 32 degrees C to 38 degrees C reversibly depressed the fast and slow components of the optical response to stimulation of the Schaffer collaterals that correspond to the presynaptic action potential and excitatory postsynaptic response, respectively. The neuronal activity recovered almost completely after cooling the hippocampal neurons back to 32 degrees C.

Contribution of nitric oxide to the depression of neuronal activity induced by temperature increase in the rat hippocampal CA1 area.

Using optical recording techniques, we examined whether nitric oxide (NO) is implicated in the impairment of the activity of hippocampal CA1 neurons induced by mild heat stress. A temperature increase from 32 to 38 degrees C reversibly depressed the neuronal activity in hippocampal slices. L-Arginine (1 mM), an NO donor, enhanced the heat-induced depression of the activity of hippocampal CA1 neurons.

Monocarboxylate transporters contribute to the adaptation of neuronal activity to repeated glucose deprivation in the rat lateral septal nucleus.

Using optical recording methods in the rat lateral septal nucleus (LSN) slice, we examined the question of whether antecedent hypoglycemia protects neurons from the adverse effects of subsequent hypoglycemic stimuli. The first exposure of LSN neurons to glucose deprivation for 15 min produced a marked depression of neuronal activity. The neuronal activity recovered by reapplication of glucose to the neurons.

Protective role of heparin/heparan sulfate on oxalate-induced changes in cell morphology and intracellular Ca2+.

Alterations in intracellular Ca2+ ([Ca2+]i) are generally associated with cellular distress. Oxalate-induced cell injury of the renal epithelium plays an important role in promoting CaOx nephrolithiasis. However, the degree of change in intracellular free calcium ions in renal epithelial cells during oxalate exposure remains unclear.

Effects of methylphenidate on the inhibitory postsynaptic potential in rat locus coeruleus neurons.

Effects of methylphenidate (MPH), an agent used clinically for the treatment of children presenting the attention-deficit/hyperactivity disorder (AD/HD), on synaptic transmission in the rat locus coeruleus (LC) were examined by intracellular recording methods. Bath-application of MPH (30 nM-3 microM) increased the amplitude of the inhibitory postsynaptic potential (IPSP), while it did not change the amplitude of the excitatory postsynaptic potential (EPSP). MPH increased the time-to-peak and the half-decay time of the IPSP in LC neurons.

Activation of presynaptic 5-hydroxytryptamine 2A receptors facilitates excitatory synaptic transmission via protein kinase C in the dorsolateral septal nucleus.

Effects of 5-hydroxytryptamine (5-HT) on EPSPs and EPSCs in the rat dorsolateral septal nucleus (DLSN) were examined in the presence of GABA(A) and GABA(B) receptor antagonists. Bath application of 5-HT (10 microm) for 5-10 min increased the amplitude of the EPSP and EPSC. (+/-)-8-hydroxy-2-(di-N-propylamino)tetralin hydrobromide (10 microm), an agonist for 5-HT1A and 5-HT7 receptors, did not facilitate the EPSP.

Hyperexcitability of hippocampal CA1 neurons after fluid percussion injury of the rat cerebral cortex.

Effects of fluid percussion injury (FPI) of the parietal cerebral cortex on the neuronal activity in the temporal region of the rat hippocampal CA1 area were investigated by using optical and extracellular recording techniques. Application of moderate impact (1.5-2.

Effects of temperature increase on the propagation of presynaptic action potentials in the pathway between the Schaffer collaterals and hippocampal CA1 neurons.

Effects of temperature increase on the neuronal activity of hippocampal CA2-CA1 regions were examined by using optical and electrophysiological recording techniques. Stimulation of the Schaffer collaterals at the CA2 region evoked depolarizing optical signals that spread toward the CA1 region at 32 degrees C. The optical signal recorded by 49 pixels was characterized by fast and slow components that were closely related to presynaptic action potentials and excitatory postsynaptic responses, respectively.

Effects of methylphenidate on the membrane potential and current in neurons of the rat locus coeruleus.

Effects of methylphenidate (MPH), a therapeutic agent used in children presenting the attention deficit hyperactivity disorder (ADHD), on the membrane potential and current in neurons of the rat locus coeruleus (LC) were examined using intracellular and whole cell patch-clamp recording techniques. Application of MPH (30 microM) to artificial cerebrospinal fluid (ACSF) produced a hyperpolarizing response with amplitude of 12 +/- 1 mV (n = 29). Spontaneous firing of LC neurons was blocked during the MPH-induced hyperpolarization.