scholarly journals Posttetanic enhancement of striato-pallidal synaptic transmission

2015 ◽  
Vol 114 (1) ◽  
pp. 447-454
Author(s):  
Juhyon Kim ◽  
Hitoshi Kita
Keyword(s):  
Brain Slice ◽  
Limiting Factor ◽  
Patch Clamp Recording ◽  
Body Movements ◽  
Pathological Conditions ◽  
Whole Cell Patch Clamp ◽  
Wide Range ◽  
Functional Implications ◽  
Rat Brain Slice ◽  
Conditioning Stimuli

The striato (Str)-globus pallidus external segment (GPe) projection plays major roles in the control of neuronal activity in the basal ganglia under both normal and pathological conditions. The present study used rat brain slice preparations to characterize the enhancement of Str-GPe synapses observed after repetitive conditioning stimuli (CS) of Str with the whole cell patch-clamp recording technique. The results show that 1) the Str-GPe synapses have a posttetanic enhancement (PTE) mechanism, which is considered to be a combination of an augmentation and a posttetanic potentiation; 2) the degree of PTE observed in GPe neurons had a wide range and was positively correlated with a wide range of paired-pulse ratios assessed before application of CS; 3) a wide range of CS, from frequencies as low as 2 Hz with as few as 5 pulses to as high as 100 Hz with 100 pulses, could induce PTE; 4) the decay time constant of PTE was dependent on the strength of CS and was prolonged greatly, up to 120 s, when strong CS were applied; and 5) the level of postsynaptic Cl− became a limiting factor for the degree of PTE when strong CS were applied. These results imply that Str-GPe synapses transmit inhibitions in a nonlinear activity-weighted manner, which may be suited for scaling timing and force of repeated or sequential body movements. Other possible factors controlling the induction of PTE and functional implications are also discussed.

scholarly journals Short-term plasticity shapes activity pattern-dependent striato-pallidal synaptic transmission

2013 ◽  
Vol 109 (4) ◽  
pp. 932-939 ◽  
Author(s):  
Juhyon Kim ◽  
Hitoshi Kita
Keyword(s):  
Synaptic Transmission ◽  
Firing Pattern ◽  
Brain Slice ◽  
Projection Neurons ◽  
Short Term ◽  
Short Term Plasticity ◽  
Pathological Conditions ◽  
Rat Brain Slice ◽  
Signal Transfer Function

The cortico-striato (Str)-globus pallidus external segment (GPe) projection plays major roles in the control of neuronal activity in the basal ganglia under both normal and pathological conditions. The present study used rat brain-slice preparations to address our hypothesis that the gain of this disynaptic projection is dynamically controlled by activations of short-term plasticity mechanisms of Str-GPe synapses. The Str-GPe projection neurons fire with very different frequency and firing patterns in vivo depending on the condition of the animal. The results show that the Str-GPe synapses have very strong short-term enhancement mechanisms and that repetitive burst activation of the Str-GPe synapses, which mimic oscillatory burst firing of Str neurons, can sustain enhanced states of synaptic transmission for tens of seconds. The results reveal that the short-term enhancement of Str-GPe synapses contributes to the generation of pauses in the firing of GPe neurons and that signal transfer function in the Str-GPe projection is highly dependent on the firing pattern of Str neurons.

Differential Short-Term Changes in GABAergic or Glycinergic Synaptic Efficacy on Rat Hypoglossal Motoneurons

2001 ◽  
Vol 86 (2) ◽  
pp. 565-574 ◽  
Author(s):  
Roberta Donato ◽  
Andrea Nistri
Keyword(s):  
Neonatal Rat ◽  
Patch Clamp Recording ◽  
Short Term ◽  
Hypoglossal Motoneurons ◽  
Whole Cell Patch Clamp ◽  
Gabaergic Synapses ◽  
Synaptic Changes ◽  
Rat Brain Slice ◽  
Neonatal Rat Brain ◽  
Brain Slice Preparation

Using whole cell patch-clamp recording from hypoglossal motoneurons of a neonatal rat brain slice preparation, we investigated short-term changes in synaptic transmission mediated by GABA or glycine. In 1.5 mM extracellular Ca2+[Ca2+]o, pharmacologically isolated GABAergic or glycinergic currents were elicited by electrical stimulation of the reticular formation. At low stimulation frequency, glycinergic currents were larger and faster than GABAergic ones. GABAergic currents were strongly facilitated by pulse trains at 5 or 10 Hz without apparent depression. This phenomenon persisted after pharmacological block of GABABreceptors. Glycinergic currents were comparatively much less enhanced than GABAergic currents. One possible mechanism to account for this difference is that GABAergic currents decayed so slowly that consecutive responses summated over an incrementing baseline. However, while synaptic summation appeared at ≥10-Hz stimulation, at 5 Hz strong facilitation developed with minimal summation of GABA-mediated currents. Glycinergic currents decayed so fast that summation was minimal. As [Ca2+]o is known to shape short-term synaptic changes, we examined if varying [Ca2+]o could differentially affect facilitation of GABA- or glycine-operated synapses. With 5 mM [Ca2+]o, the frequency of spontaneous GABAergic or glycinergic currents appeared much higher but GABAergic current facilitation was blocked (and replaced by depression), whereas glycinergic currents remained slightly facilitated. [Ca2+]omanipulation thus brought about distinct processes responsible for facilitation of GABAergic or glycinergic transmission. Our data therefore demonstrate an unexpectedly robust, short-term increase in the efficiency of GABAergic synapses that can become at least as effective as glycinergic synapses.

scholarly journals When the Balance Tips: Dysregulation of Mitochondrial Dynamics as a Culprit in Disease

2021 ◽  
Vol 22 (9) ◽  
pp. 4617
Author(s):  
Styliana Kyriakoudi ◽  
Anthi Drousiotou ◽  
Petros P. Petrou
Keyword(s):  
Insulin Resistance ◽  
Mitochondrial Function ◽  
Human Disease ◽  
Molecular Mechanisms ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fusion ◽  
Mitochondrial Morphology ◽  
Disease Development ◽  
Pathological Conditions ◽  
Wide Range

Mitochondria are dynamic organelles, the morphology of which is tightly linked to their functions. The interplay between the coordinated events of fusion and fission that are collectively described as mitochondrial dynamics regulates mitochondrial morphology and adjusts mitochondrial function. Over the last few years, accruing evidence established a connection between dysregulated mitochondrial dynamics and disease development and progression. Defects in key components of the machinery mediating mitochondrial fusion and fission have been linked to a wide range of pathological conditions, such as insulin resistance and obesity, neurodegenerative diseases and cancer. Here, we provide an update on the molecular mechanisms promoting mitochondrial fusion and fission in mammals and discuss the emerging association of disturbed mitochondrial dynamics with human disease.

scholarly journals Orexin depolarizes rat hypothalamic paraventricular nucleus neurons

2001 ◽  
Vol 281 (4) ◽  
pp. R1114-R1118 ◽  
Author(s):  
Tetsuro Shirasaka ◽  
Satoshi Miyahara ◽  
Takato Kunitake ◽  
Qing-Hua Jin ◽  
Kazuo Kato ◽  
...  
Keyword(s):  
Paraventricular Nucleus ◽  
Brain Slices ◽  
Hypothalamic Paraventricular Nucleus ◽  
Dependent Manner ◽  
Patch Clamp Recording ◽  
Concentration Dependent Manner ◽  
Whole Cell Patch Clamp ◽  
Orexin Receptors ◽  
Bath Application

Orexins, also called hypocretins, are newly discovered hypothalamic peptides that are thought to be involved in various physiological functions. In spite of the fact that orexin receptors, especially orexin receptor 2, are abundant in the hypothalamic paraventricular nucleus (PVN), the effects of orexins on PVN neurons remain unknown. Using a whole cell patch-clamp recording technique, we investigated the effects of orexin-B on PVN neurons of rat brain slices. Bath application of orexin-B (0.01–1.0 μM) depolarized 80.8% of type 1 ( n = 26) and 79.2% of type 2 neurons tested ( n = 24) in the PVN in a concentration-dependent manner. The effects of orexin-B persisted in the presence of TTX (1 μM), indicating that these depolarizing effects were generated postsynaptically. Addition of Cd2+(1 mM) to artificial cerebrospinal fluid containing TTX (1 μM) significantly reduced the depolarizing effect in type 2 neurons. These results suggest that orexin-B has excitatory effects on the PVN neurons mediated via a depolarization of the membrane potential.

23. A new adult rat brain slice preparation for ex vivo NMR spectroscopy studies of stroke

1994 ◽  
Vol 52 (1) ◽  
pp. A11
Author(s):  
M.T. Espanol ◽  
L. Litt ◽  
L.-H. Chang ◽  
T.L. James ◽  
P.R. Weinstein ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Rat Brain ◽  
Brain Slice ◽  
Ex Vivo ◽  
Slice Preparation ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Spectroscopy Studies ◽  
Rat Brain Slice ◽  
Brain Slice Preparation

Lateral skull base surgery: a complicated pursuit?

2007 ◽  
Vol 122 (3) ◽  
pp. 221-229
Author(s):  
V C Cousins
Keyword(s):  
Skull Base ◽  
Skull Base Surgery ◽  
Treatment Modalities ◽  
Published Data ◽  
Know How ◽  
Team Assessment ◽  
Pathological Conditions ◽  
Lateral Skull Base ◽  
Wide Range ◽  
Multi Disciplinary Team

AbstractThe management of lesions of the lateral skull base is a highly sophisticated branch of surgery generally performed by otolaryngology–head and neck surgeons as part of a multi-disciplinary team. Assessment of patients with diseases affecting the lateral skull base can be complex, as can the application of the various treatment modalities and the management of the expected and unexpected side effects of that treatment.A wide range of pathological conditions occur in the lateral skull base. Many operations and procedures have been described for dealing with them. There is not necessarily one correct solution to the management of any particular problem in the skull base, with multiple factors to be considered in planning and intervention.As surgeons, we need to know how our own results and outcomes compare with pooled, published data concerning the implications and complications occurring as a result of intervention, in order to better advise our patients on their management.

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