Patch-Pipette Recordings from the Soma, Dendrites, and Axon of Neurons in Brain Slices

1995 ◽  
pp. 199-211 ◽  
Author(s):  
Bert Sakmann ◽  
Greg Stuart
Keyword(s):  
Brain Slices ◽  
Patch Pipette

Potentiation of a slow Ca(2+)-dependent K+ current by intracellular Ca2+ chelators in hippocampal CA1 neurons of rat brain slices

1995 ◽  
Vol 74 (6) ◽  
pp. 2225-2241 ◽  
Author(s):  
L. Zhang ◽  
P. Pennefather ◽  
A. Velumian ◽  
M. Tymianski ◽  
M. Charlton ◽  
...  
Keyword(s):  
Decay Time ◽  
Time Course ◽  
Brain Slices ◽  
Tetraacetic Acid ◽  
Pipette Solution ◽  
Ca1 Neurons ◽  
High Affinity ◽  
Hippocampal Ca1 ◽  
Patch Pipette ◽  
K Current

1. In hippocampal CA1 neurons of rat brain slices, a Ca(2+)-dependent slow afterhyperpolarization (sAHP) and underlying K+ current (IsAHP) are activated by Ca2+ influx and presumably reflect the time course of the intracellular Ca2+ signal produced by neuronal stimulation. We tested the hypothesis that when exogenous Ca2+ chelators become the predominant mobile Ca2+ buffer in the neuron, they alter the shape of intracellular Ca2+ signals responsible for IsAHP. The nature of this alteration provides insight into the mechanism of IsAHP generation. 2. Derivatives of 1,2-bis-[2-amino phenoxy] ethane N,N,N',N' tetraacetic acid (BAPTA) with different dissociation constants (KDS) for Ca2+ ranging from 0.15 to 7,000 microM were used to test this hypothesis. We also examined the effects of ethylene glycolbis (beta-aminoethyl either)-N,N,N',N'-tetraacetic acid (EGTA), which has a KD similar to that of BAPTA for Ca2+, but which binds and releases Ca2+ 100 times more slowly. When delivered to the cytoplasm by dialysis from a patch pipette, these chelators potentiated, inhibited, or had no effect on IsAHP depending on their concentration, affinity, and binding kinetics. 3. IsAHP decayed exponentially over much of its time course, with a half-decay time of 0.9 +/- 0.1 s (mean +/- SE, n = 22). Immediately after breakthrough into the whole cell configuration, there was an initial period of approximately 5 min during which IsAHP magnitude increased approximately 3.5-fold with no change in time course. Thereafter, the time course and amplitude of IsAHP were stable for > 45 min. 4. Addition of 1 mM of the high-affinity chelators 5,5'-dimethyl BAPTA or BAPTA to the pipette solution first increased the decay time of IsAHP 1.5-fold. However, within 10-15 min after break-through, the current was abolished. Addition of Ca2+ (0.1-1.0 mM) to the patch pipette containing the BAPTA derivatives reduced the ability of a given concentration of high-affinity chelator to inhibit IsAHP and also prolonged the period of IsAHP enhancement. A similar prolongation of the period of enhancement with even less attenuation of IsAHP was apparent with 0.1 mM 5,5'-dimethyl BAPTA and 0.1 mM Ca2+. 5. The intermediate-affinity chelator 4.4'-difluoro BAPTA (1 mM) prolonged the decay phase of the sAHP/IsAHP without attenuating the current. A twofold prolongation of IsAHP also was observed in neurons dialyzed with internal solution containing 3 mM EGTA and 0.3 mM Ca2+. Dialysis with 1 mM of the low-affinity chelators 2-amino-5-fluorophenol-N,N,O-triacetic acid (5-fluoro APTRA) or 5,5'-dinitro BAPTA had no apparent effect on IsAHP. All of the chelators that prolonged the decay phase of IsAHP also induced a rising phase such that a well-defined peak of IsAHP could be discerned at approximately 0.6 s after the end of the stimulus used to evoke the current. 6. Weak stimulation of muscarinic receptors selectively inhibits IsAHP. Thus the uncontaminated time course of IsAHP can be deduced by subtracting currents recorded before and after such muscarinic stimulation. With minimal exogenous buffer in the pipette (0.1 mM EGTA), the muscarinic-receptor-sensitive current exhibited a rising phase lasting approximately 300 ms and then decayed with a half-time of approximately 1 s. Both the rising and decay phases of the muscarinic-receptor-sensitive current were prolonged at least twofold by dialysis with BAPTA or 4,4'-difluoro BAPTA. Thus the effect of the chelators on the time course of IsAHP is not simply and artifact of inhibition of early components of the outward current. 7. The effects of BAPTA analogues on the time course of IsAHP are not due to changes in mobilization of intracellular Ca2+. External application of caffeine (10 mM), ryanodine (20 microM), dantrolene (20 microM), or thapsigargin (100 microM) had no effect on IsAHP recorded with the standard pipette solution or

Sigma receptors mediate potent neuroprotection in vivo and inhibit neuronal depolarisation and swelling in rat brain slices

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S468-S468
Author(s):  
Jennifer K Callaway ◽  
Christine Molnar ◽  
Song T Yao ◽  
Bevyn Jarrott ◽  
R David Andrew
Keyword(s):  
Rat Brain ◽  
Brain Slices ◽  
Sigma Receptors

Atypical amino acids inhibit histidine, valine, or lysine transport into rat brain

1983 ◽  
Vol 245 (4) ◽  
pp. R556-R563 ◽  
Author(s):  
J. K. Tews ◽  
A. E. Harper
Keyword(s):  
Amino Acids ◽  
Rat Brain ◽  
Blood Brain Barrier ◽  
Brain Slices ◽  
Aromatic Amino Acids ◽  
Brain Barrier ◽  
Basic Amino Acids ◽  
Large Neutral Amino Acids ◽  
Neutral Amino Acids ◽  
Single Meal

Transport of histidine, valine, or lysine into rat brain slices and across the blood-brain barrier (BBB) was determined in the presence of atypical nonprotein amino acids. Competitors of histidine and valine transport in slices were large neutral amino acids including norleucine, norvaline, alpha-aminooctanoate, beta-methylphenylalanine, and alpha-aminophenylacetate. Less effective were aromatic amino acids with ring substituents; ineffective were basic amino acids and omega-amino isomers of norleucine and aminooctanoate. Lysine transport was moderately depressed by homoarginine or ornithine plus arginine; large neutral amino acids were also similarly inhibitory. Histidine or valine transport across the BBB was also strongly inhibited by large neutral amino acids that were the most effective competitors in the slices (norvaline, norleucine, alpha-aminooctanoate, and alpha-aminophenylacetate); homoarginine and 8-aminooctanoate were ineffective. Homoarginine, ornithine, and arginine almost completely blocked lysine transport, but the large neutral amino acids were barely inhibitory. When rats were fed a single meal containing individual atypical large neutral amino acids or homoarginine, brain pools of certain large neutral amino acids or of arginine and lysine, respectively, were depleted.

scholarly journals Oxytocin Modulation of Maternal Behavior and Its Association With Immunological Activity in Rats With Cesarean Delivery

ASN NEURO ◽  
2021 ◽  
Vol 13 ◽  
pp. 175909142110147
Author(s):  
Tong Li ◽  
Shu-Wei Jia ◽  
Dan Hou ◽  
Xiaoran Wang ◽  
Dongyang Li ◽  
...  
Keyword(s):  
Cesarean Delivery ◽  
Maternal Behavior ◽  
Inflammatory Cytokine ◽  
Adrenocorticotropic Hormone ◽  
Brain Slices ◽  
Relative Weight ◽  
Resting Membrane Potential ◽  
Cytokine Release ◽  
Immunological Activity ◽  
Fos Expression

Oxytocin (OT), a neuropeptide produced in the supraoptic (SON) and paraventricular (PVN) nuclei, is not only essential for lactation and maternal behavior but also for normal immunological activity. However, mechanisms underlying OT regulation of maternal behavior and its association with immunity around parturition, particularly under mental and physical stress, remain unclear. Here, we observed effects of OT on maternal behavior in association with immunological activity in rats after cesarean delivery (CD), a model of reproductive stress. CD significantly reduced maternal interests to the pups throughout postpartum day 1-8. On postpartum day 5, CD decreased plasma OT levels and thymic index but increased vasopressin, interleukin (IL)-1β, IL-6 and IL-10 levels. CD had no significant effect on plasma adrenocorticotropic hormone and corticosterone levels. In the hypothalamus, CD decreased corticotropin-releasing hormone contents in the PVN but increased OT contents in the PVN and SON and OT release from hypothalamic implants. CD also increased c-Fos expression, particularly in the cytoplasm of OT neurons. Lastly, CD depolarized resting membrane potential and increased spike width while increasing the variability of the firing rate of OT neurons in brain slices. Thus, CD can increase hypothalamic OT contents and release but reduce pituitary release of OT into the blood, which is associated with depressive-like maternal behavior, increased inflammatory cytokine release and decreased relative weight of the thymus.

scholarly journals Difluoroboron β-diketonate polylactic acid oxygen nanosensors for intracellular neuronal imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meng Zhuang ◽  
Suchitra Joshi ◽  
Huayu Sun ◽  
Tamal Batabyal ◽  
Cassandra L. Fraser ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Oxygen Sensing ◽  
Brain Slices ◽  
Neuronal Cell ◽  
Quantum Yields ◽  
Poly Lactic Acid ◽  
Neuronal Cultures ◽  
Primary Neuronal Cultures ◽  
Non Invasive ◽  
Mitotracker Red

AbstractCritical for metabolism, oxygen plays an essential role in maintaining the structure and function of neurons. Oxygen sensing is important in common neurological disorders such as strokes, seizures, or neonatal hypoxic–ischemic injuries, which result from an imbalance between metabolic demand and oxygen supply. Phosphorescence quenching by oxygen provides a non-invasive optical method to measure oxygen levels within cells and tissues. Difluoroboron β-diketonates are a family of luminophores with high quantum yields and tunable fluorescence and phosphorescence when embedded in certain rigid matrices such as poly (lactic acid) (PLA). Boron nanoparticles (BNPs) can be fabricated from dye-PLA materials for oxygen mapping in a variety of biological milieu. These dual-emissive nanoparticles have oxygen-insensitive fluorescence, oxygen-sensitive phosphorescence, and rigid matrix all in one, enabling real-time ratiometric oxygen sensing at micron-level spatial and millisecond-level temporal resolution. In this study, BNPs are applied in mouse brain slices to investigate oxygen distributions and neuronal activity. The optical properties and physical stability of BNPs in a biologically relevant buffer were stable. Primary neuronal cultures were labeled by BNPs and the mitochondria membrane probe MitoTracker Red FM. BNPs were taken up by neuronal cell bodies, at dendrites, and at synapses, and the localization of BNPs was consistent with that of MitoTracker Red FM. The brain slices were stained with the BNPs, and the BNPs did not significantly affect the electrophysiological properties of neurons. Oxygen maps were generated in living brain slices where oxygen is found to be mostly consumed by mitochondria near synapses. Finally, the BNPs exhibited excellent response when the conditions varied from normoxic to hypoxic and when the neuronal activity was increased by increasing K+ concentration. This work demonstrates the capability of BNPs as a non-invasive tool in oxygen sensing and could provide fundamental insight into neuronal mechanisms and excitability research.

scholarly journals Comparative analysis of spreading depolarizations in brain slices exposed to osmotic or metabolic stress

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Rita Frank ◽  
Ferenc Bari ◽  
Ákos Menyhárt ◽  
Eszter Farkas
Keyword(s):  
Osmotic Stress ◽  
Tissue Injury ◽  
Brain Slices ◽  
Field Potential ◽  
Metabolic Stress ◽  
Glucose Deprivation ◽  
Optical Signal ◽  
Light Illumination ◽  
Glass Capillary ◽  
Experimental Conditions

Abstract Background Recurrent spreading depolarizations (SDs) occur in stroke and traumatic brain injury and are considered as a hallmark of injury progression. The complexity of conditions associated with SD in the living brain encouraged researchers to study SD in live brain slice preparations, yet methodological differences among laboratories complicate integrative data interpretation. Here we provide a comparative evaluation of SD evolution in live brain slices, in response to selected SD triggers and in various media, under otherwise standardized experimental conditions. Methods Rat live coronal brain slices (350 μm) were prepared (n = 51). Hypo-osmotic medium (Na+ content reduced from 130 to 60 mM, HM) or oxygen-glucose deprivation (OGD) were applied to cause osmotic or ischemic challenge. Brain slices superfused with artificial cerebrospinal fluid (aCSF) served as control. SDs were evoked in the control condition with pressure injection of KCl or electric stimulation. Local field potential (LFP) was recorded via an intracortical glass capillary electrode, or intrinsic optical signal imaging was conducted at white light illumination to characterize SDs. TTC and hematoxylin-eosin staining were used to assess tissue damage. Results Severe osmotic stress or OGD provoked a spontaneous SD. In contrast with SDs triggered in aCSF, these spontaneous depolarizations were characterized by incomplete repolarization and prolonged duration. Further, cortical SDs under HM or OGD propagated over the entire cortex and occassionally invaded the striatum, while SDs in aCSF covered a significantly smaller cortical area before coming to a halt, and never spread to the striatum. SDs in HM displayed the greatest amplitude and the most rapid propagation velocity. Finally, spontaneous SD in HM and especially under OGD was followed by tissue injury. Conclusions While the failure of Na+/K+ ATP-ase is thought to impair tissue recovery from OGD-related SD, the tissue swelling-related hyper excitability and the exhaustion of astrocyte buffering capacity are suggested to promote SD evolution under osmotic stress. In contrast with OGD, SD propagating under hypo-osmotic condition is not terminal, yet it is associated with irreversible tissue injury. Further investigation is required to understand the mechanistic similarities or differences between the evolution of SDs spontaneously occurring in HM and under OGD.

scholarly journals The Entorhinal Cortical Alvear Pathway Differentially Excites Pyramidal Cells and Interneuron Subtypes in Hippocampal CA1

2020 ◽  
Author(s):  
Karen A Bell ◽  
Rayne Delong ◽  
Priyodarshan Goswamee ◽  
A Rory McQuiston
Keyword(s):  
Brain Slices ◽  
Pyramidal Cells ◽  
Excitatory Input ◽  
Theta Burst Stimulation ◽  
Ca1 Pyramidal Cells ◽  
Whole Cell Patch Clamp ◽  
Hippocampal Ca1 ◽  
Physiological Impact ◽  
Theta Burst ◽  
Synaptic Responses

Abstract The entorhinal cortex alvear pathway is a major excitatory input to hippocampal CA1, yet nothing is known about its physiological impact. We investigated the alvear pathway projection and innervation of neurons in CA1 using optogenetics and whole cell patch clamp methods in transgenic mouse brain slices. Using this approach, we show that the medial entorhinal cortical alvear inputs onto CA1 pyramidal cells (PCs) and interneurons with cell bodies located in stratum oriens were monosynaptic, had low release probability, and were mediated by glutamate receptors. Optogenetic theta burst stimulation was unable to elicit suprathreshold activation of CA1 PCs but was capable of activating CA1 interneurons. However, different subtypes of interneurons were not equally affected. Higher burst action potential frequencies were observed in parvalbumin-expressing interneurons relative to vasoactive-intestinal peptide-expressing or a subset of oriens lacunosum-moleculare (O-LM) interneurons. Furthermore, alvear excitatory synaptic responses were observed in greater than 70% of PV and VIP interneurons and less than 20% of O-LM cells. Finally, greater than 50% of theta burst-driven inhibitory postsynaptic current amplitudes in CA1 PCs were inhibited by optogenetic suppression of PV interneurons. Therefore, our data suggest that the alvear pathway primarily affects hippocampal CA1 function through feedforward inhibition of select interneuron subtypes.

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