scholarly journals Anticonvulsant effect of dipropofol by enhancing native GABA currents in cortical neurons in mice

2018 ◽  
Vol 120 (3) ◽  
pp. 1404-1414 ◽  
Author(s):  
Jingliang Zhang ◽  
Xiaoling Chen ◽  
Matti Kårbø ◽  
Yi Zhao ◽  
Long An ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Mouse Model ◽  
Kainic Acid ◽  
Neuronal Excitability ◽  
Brain Slices ◽  
Anticonvulsant Effect ◽  
Dependent Manner ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Dose Dependent

Temporal lobe epilepsy (TLE), the most common pharmacoresistant focal epilepsy disorder, remains a major unmet medical need. Propofol is used as a short-acting medication for general anesthesia and refractory status epilepticus with issues of decreased consciousness and memory loss. Dipropofol, a derivative of propofol, has been reported to exert antioxidative and antibacterial activities. Here we report that dipropofol exerted anticonvulsant activity in a mouse model of kainic acid-induced seizures. Whole cell patch-clamp recordings of brain slices from the medial entorhinal cortex (mEC) revealed that dipropofol hyperpolarized the resting membrane potential and reduced the number of action potential firings, resulting in suppression of cortical neuronal excitability. Furthermore, dipropofol activated native tonic GABAA currents of mEC layer II stellate neurons in a dose-dependent manner with an EC50 value of 9.3 ± 1.6 μM (mean ± SE). Taken together, our findings show that dipropofol activated GABAA currents and exerted anticonvulsant activities in mice, thus possessing developmental potential for new anticonvulsant therapy. NEW & NOTEWORTHY The anticonvulsant effect of dipropofol was shown in a mouse model of kainic acid-induced seizures. Whole cell patch-clamp recordings of brain slices showed suppression of cortical neuronal excitability by dipropofol. Dipropofol activated the native tonic GABAA currents in a dose-dependent manner.

Acute reduction in whole cell conductance in anoxic turtle brain

1999 ◽  
Vol 277 (3) ◽  
pp. R887-R893 ◽  
Author(s):  
H. S. Ghai ◽  
L. T. Buck
Keyword(s):  
Brain Slices ◽  
Cell Voltage ◽  
Dependent Manner ◽  
Recording Electrode ◽  
Whole Cell ◽  
Artificial Cerebrospinal Fluid ◽  
Intracellular Ca ◽  
Specific Antagonist ◽  
Acute Changes ◽  
Dose Dependent

We tested the effect of anoxia, a “mimic” turtle artificial cerebrospinal fluid (aCSF) consisting of high Ca2+ and Mg2+ concentrations and low pH and adenosine perfusions, on whole cell conductance ( G w) in turtle brain slices using a whole cell voltage-clamp technique. With EGTA in the recording electrode, anoxic or adenosine perfusions did not change G w significantly (values range between 2.15 ± 0.24 and 3.24 ± 0.56 nS). However, perfusion with normoxic or anoxic mimic aCSF significantly decreased G w. High [Ca2+] (4.0 or 7.8 mM) perfusions alone could reproduce the changes in G w found with the mimic perfusions. With the removal of EGTA from the recording electrode, G wdecreased significantly during both anoxic and adenosine perfusions. The A1-receptor agonist N 6-cyclopentyladenosine reduced G w in a dose-dependent manner, whereas the A1-receptor specific antagonist 8-cyclopentyl-1,3-dipropylxanthine blocked both the adenosine- and anoxic-mediated changes in G w. These data suggest a mechanism involving A1-receptor-mediated changes in intracellular [Ca2+] that result in acute changes in G w with the onset of anoxia.

scholarly journals Chemogenetic activation of excitatory neurons alters hippocampal neurotransmission in a dose-dependent manner

2019 ◽  
Author(s):  
Sthitapranjya Pati ◽  
Sonali S. Salvi ◽  
Mamata Kallianpur ◽  
Antara Banerjee ◽  
Sudipta Maiti ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Neuronal Firing ◽  
Whole Cell ◽  
Cell Patch Clamp ◽  
Whole Cell Patch Clamp ◽  
Excitatory Neurons ◽  
Excitatory Neurotransmission ◽  
Dose Dependent ◽  
Fepsp Slope

AbstractDesigner Receptors Exclusively Activated by Designer Drugs (DREADD)-based chemogenetic tools are extensively used to manipulate neuronal activity in a cell-type specific manner. Whole-cell patch-clamp recordings indicate membrane depolarization, coupled with increased neuronal firing rate, following administration of the DREADD ligand, Clozapine-N-Oxide (CNO) to activate the Gq-coupled DREADD, hM3Dq. Although hM3Dq has been used to enhance neuronal firing in order to manipulate diverse behaviors, often within thirty minutes to an hour post-CNO administration, the physiological effects on excitatory neurotransmission remain poorly understood. We investigated the influence of CNO-mediated hM3Dq DREADD activation on distinct aspects of hippocampal excitatory neurotransmission at the Schaffer collateral-CA1 synapse in hippocampal slices derived from mice expressing hM3Dq in Ca2+/calmodulin dependent protein kinase α (CamKIIα)-positive excitatory neurons. Our results indicate a clear dose-dependent effect on fEPSP slope, with no change noted at the lower dose of CNO (1 µM) and a significant, long-term decline in fEPSP slope observed at higher doses (5-20 µM). Further, we noted a robust theta burst stimulus (TBS) induced long-term potentiation (LTP) in the presence of the lower CNO (1 µM) dose, which was significantly attenuated at the higher CNO (20 µM) dose. Whole-cell patch clamp recording revealed both complex dose-dependent regulation of excitability, and spontaneous and evoked activity of CA1 pyramidal neurons in response to hM3Dq activation across CNO concentrations. Our data indicate that CNO-mediated activation of the hM3Dq DREADD results in dose-dependent regulation of excitatory hippocampal neurotransmission, and highlight the importance of careful interpretation of behavioral experiments involving chemogenetic manipulation.

scholarly journals Inhibition of cardiac Na+ currents by isoproterenol

1990 ◽  
Vol 258 (4) ◽  
pp. H977-H982 ◽  
Author(s):  
B. Schubert ◽  
A. M. Vandongen ◽  
G. E. Kirsch ◽  
A. M. Brown
Keyword(s):  
Patch Clamp ◽  
Ventricular Myocytes ◽  
Neonatal Rat ◽  
Na Channel ◽  
Dependent Manner ◽  
Patch Clamp Technique ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Na Currents ◽  
Voltage Dependent

The mechanism by which the beta-adrenergic agonist isoproterenol (ISO) modulates voltage-dependent cardiac Na+ currents (INa) was studied in single ventricular myocytes of neonatal rat using the gigaseal patch-clamp technique. ISO inhibited INa reversibly, making the effect readily distinguishable from the monotonic decrease of INa caused by the shift in gating that customarily occurs during whole cell patch-clamp experiments (E. Fenwick, A. Marty, and E. Neher, J. Physiol. Lond. 331: 599-635, 1982; and J. M. Fernandez, A. P. Fox, and S. Krasne, J. Physiol. Lond. 356: 565-585, 1984). The inhibition was biphasic, having fast and slow components, and was voltage-dependent, being more pronounced at depolarized potentials. In whole cell experiments the membrane-permeable adenosine 3',5'-cyclic monophosphate (cAMP) congener 8-bromo-cAMP reduced INa. In cell-free inside-out patches with ISO present in the pipette, guanosine 5'-triphosphate (GTP) applied to the inner side of the membrane patch inhibited single Na+ channel activity. This inhibition could be partly reversed by hyperpolarizing prepulses. The nonhydrolyzable GTP analogue guanosine-5'-O-(3-thiotriphosphate) greatly reduced the probability of single Na+ channel currents in a Mg2(+)-dependent manner. We propose that ISO inhibits cardiac Na+ channels via the guanine nucleotide binding, signal-transducing G protein that acts through both direct (membrane delimited) and indirect (cytoplasmic) pathways.

Functional and molecular evidence for P2X receptors in LLC-PK1 cells

1998 ◽  
Vol 274 (6) ◽  
pp. F1070-F1077 ◽  
Author(s):  
Dragana M. Filipovic ◽  
Olugbenga A. Adebanjo ◽  
Mone Zaidi ◽  
W. Brian Reeves
Keyword(s):  
Patch Clamp ◽  
Purinergic Receptors ◽  
P2x Receptors ◽  
Membrane Receptors ◽  
Molecular Evidence ◽  
Rt Pcr ◽  
Whole Cell ◽  
Whole Cell Patch Clamp ◽  
Polymerase Chain ◽  
Dose Dependent

Extracellular ATP affects a wide variety of cells via purinergic membrane receptors. One class of purinergic receptors, P2X, consists of ATP-gated, calcium-permeable, cation-selective channels. We performed whole cell patch-clamp studies, intracellular calcium concentration ([Ca2+]i) measurements, and reverse transcription-polymerase chain reaction (RT-PCR) to determine whether P2X receptors are expressed in LLC-PK1 cells. First, in patch-clamp studies, 100 μM ATP depolarized the cell membrane and increased the whole cell conductance of LLC-PK1 cells. This response was dose dependent and inhibited by 100 μM suramin, a P2 receptor antagonist. The ATP-induced conductance was cation selective but did not discriminate between Na+ and K+. ADP, α,β-methylene-ATP, and β,γ-methylene-ATP had no effect on the whole cell conductance. Next, 10 μM ATP caused a rapid rise in [Ca2+]iin LLC-PK1 cells. This effect of ATP was inhibited by the absence of extracellular calcium and by suramin but not by pretreatment with pertussis toxin. ADP and β,γ-methylene- ATP had little or no effect on [Ca2+]i. Finally, RT-PCR produced a 330-bp fragment from LLC-PK1 cell RNA, whose sequence was 80% identical to the rat P2X1receptor. We conclude that LLC-PK1cells express purinergic receptors of the P2X class, which mediate depolarization and calcium entry when activated.

scholarly journals Investigation of Neuron Latency Modulated by Bilateral Inferior Collicular Interactions Using Whole-Cell Patch Clamp Recording in Brain Slices

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jinzhe Ma ◽  
Yangyang Han ◽  
Yiting Yao ◽  
Huimei Wang ◽  
Mengxia Chen ◽  
...  
Keyword(s):  
Patch Clamp ◽  
Synaptic Input ◽  
Brain Slices ◽  
Inhibitory Neurons ◽  
Patch Clamp Recording ◽  
Whole Cell ◽  
Cell Patch Clamp ◽  
Whole Cell Patch Clamp ◽  
Inferior Collicular ◽  
Latency Variation

As the final level of the binaural integration center in the subcortical nucleus, the inferior colliculus (IC) plays an essential role in receiving binaural information input. Previous studies have focused on how interactions between the bilateral IC affect the firing rate of IC neurons. However, little is known concerning how the interactions within the bilateral IC affect neuron latency. In this study, we explored the synaptic mechanism of the effect of bilateral IC interactions on the latency of IC neurons. We used whole-cell patch clamp recordings to assess synaptic responses in isolated brain slices of Kunming mice. The results demonstrated that the excitation-inhibition projection was the main projection between the bilateral IC. Also, the bilateral IC interactions could change the reaction latency of most neurons to different degrees. The variation in latency was related to the type of synaptic input and the relative intensity of the excitation and inhibition. Furthermore, the latency variation also was caused by the duration change of the first subthreshold depolarization firing response of the neurons. The distribution characteristics of the different types of synaptic input also differed. Excitatory-inhibitory neurons were widely distributed in the IC dorsal and central nuclei, while excitatory neurons were relatively concentrated in these two nuclei. Inhibitory neurons did not exhibit any apparent distribution trend due to the small number of assessed neurons. These results provided an experimental reference to reveal the modulatory functions of bilateral IC projections.

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