Activation of subfornical organ neurons in rats through pre- and postsynaptic α-adrenoceptors

2006 ◽  
Vol 290 (6) ◽  
pp. R1646-R1653 ◽  
Author(s):  
Eiko Honda ◽  
Kentaro Ono ◽  
Shinji Kataoka ◽  
Kiyotoshi Inenaga
Keyword(s):  
Gaba Receptor ◽  
Membrane Conductance ◽  
Subfornical Organ ◽  
Patch Clamp Recording ◽  
Pcr Assay ◽  
Whole Cell Patch Clamp ◽  
Outward Currents ◽  
Current Clamp Mode ◽  
Inward Currents ◽  
Pulse Stimulation

The effects of noradrenaline (NA) and its analogs on subfornical organ (SFO) neurons in rat slice preparations were investigated by using whole cell patch-clamp recording. In the current-clamp mode, the application of NA at 10–100 μM produced membrane depolarization (63%, 17 responsive neurons/27 neurons tested) and hyperpolarization (22%, 6/27 neurons). In the voltage-clamp mode, NA application at 1–100 μM produced inward currents (69%, 42/61 neurons) and outward currents (23%, 14/61 neurons). These currents remained in the presence of TTX or both glutamate and GABA receptor antagonists. In most of the neurons (25/31 neurons) showing inward currents in the presence of NA, the membrane conductance was not changed by voltage ramps or hyperpolarizing pulse stimulation. Similar responses were obtained by the application of the α1-agonist phenylephrine. The phenylephrine-induced inward currents were inhibited by the α1-antagonist prazosin. The α2-agonist clonidine decreased the frequency of spontaneous GABAergic inhibitory postsynaptic currents (4/10 neurons). In addition, RT-PCR assay and immunohistochemical staining showed the existence of α1-adrenoceptors in the SFO. The results suggest that SFO neurons in rats are activated postsynaptically through α1-adrenoceptors and that the activation is enhanced by suppressing GABAergic inhibitory synaptic inputs through presynaptic α2-adrenoceptors.

scholarly journals Large-Conductance Calcium-Activated Potassium Channels and Voltage-Dependent Sodium Channels in Human Cementoblasts

2021 ◽  
Vol 12 ◽  
Author(s):  
Satomi Kamata ◽  
Maki Kimura ◽  
Sadao Ohyama ◽  
Shuichiro Yamashita ◽  
Yoshiyuki Shibukawa
Keyword(s):  
Alveolar Bone ◽  
Attachment Site ◽  
Ionic Currents ◽  
Ionic Channels ◽  
Patch Clamp Recording ◽  
Physiological Processes ◽  
Whole Cell Patch Clamp ◽  
Outward Currents ◽  
Voltage Dependent ◽  
Inward Currents

Cementum, which is excreted by cementoblasts, provides an attachment site for collagen fibers that connect to the alveolar bone and fix the teeth into the alveolar sockets. Transmembrane ionic signaling, associated with ionic transporters, regulate various physiological processes in a wide variety of cells. However, the properties of the signals generated by plasma membrane ionic channels in cementoblasts have not yet been described in detail. We investigated the biophysical and pharmacological properties of ion channels expressed in human cementoblast (HCEM) cell lines by measuring ionic currents using conventional whole-cell patch-clamp recording. The application of depolarizing voltage steps in 10 mV increments from a holding potential (Vh) of −70 mV evoked outwardly rectifying currents at positive potentials. When intracellular K+ was substituted with an equimolar concentration of Cs+, the outward currents almost disappeared. Using tail current analysis, the contributions of both K+ and background Na+ permeabilities were estimated for the outward currents. Extracellular application of tetraethylammonium chloride (TEA) and iberiotoxin (IbTX) reduced the densities of the outward currents significantly and reversibly, whereas apamin and TRAM-34 had no effect. When the Vh was changed to −100 mV, we observed voltage-dependent inward currents in 30% of the recorded cells. These results suggest that HCEM express TEA- and IbTX-sensitive large-conductance Ca2+-activated K+ channels and voltage-dependent Na+ channels.

Local Excitatory Circuits in the Intermediate Gray Layer of the Superior Colliculus

1999 ◽  
Vol 81 (3) ◽  
pp. 1424-1427 ◽  
Author(s):  
Diana L. Pettit ◽  
Matthew C. Helms ◽  
Psyche Lee ◽  
George J. Augustine ◽  
William C. Hall
Keyword(s):  
Superior Colliculus ◽  
Intermediate Layer ◽  
Tree Shrew ◽  
Patch Clamp Recording ◽  
Inward Current ◽  
Whole Cell Patch Clamp ◽  
Synaptic Interactions ◽  
Layer Neuron ◽  
Inward Currents ◽  
Synaptic Responses

Local excitatory circuits in the intermediate gray layer of the superior colliculus. We have used photostimulation and whole cell patch-clamp recording techniques to examine local synaptic interactions in slices from the superior colliculus of the tree shrew. Uncaging glutamate 10–75 μm from the somata of neurons in the intermediate gray layer elicited a long-lasting inward current, due to direct activation of glutamate receptors on these neurons, and brief inward currents caused by activation of presynaptic neurons. The synaptic responses occurred as individual currents or as clusters that lasted up to several hundred milliseconds. Excitatory synaptic responses, which reversed at membrane potentials near 0 mV, could be evoked by uncaging glutamate anywhere within 75 μm of an intermediate layer neuron. Our results indicate the presence of extensive local excitatory circuits in the intermediate layer of the superior colliculus and support the hypothesis that such intrinsic circuitry contributes to the development of presaccadic command bursts.

Homomeric RDL and Heteromeric RDL/LCCH3 GABA Receptors in the Honeybee Antennal Lobes: Two Candidates for Inhibitory Transmission in Olfactory Processing

2010 ◽  
Vol 103 (1) ◽  
pp. 458-468 ◽  
Author(s):  
Julien Pierre Dupuis ◽  
Michaël Bazelot ◽  
Guillaume Stéphane Barbara ◽  
Sandrine Paute ◽  
Monique Gauthier ◽  
...  
Keyword(s):  
Information Processing ◽  
Chloride Channel ◽  
Gaba Receptors ◽  
Gaba Receptor ◽  
Chloride Channels ◽  
Physiological Role ◽  
Inhibitory Transmission ◽  
Olfactory Information ◽  
Whole Cell Patch Clamp ◽  
Inward Currents

γ-Aminobutyric acid (GABA)–gated chloride channel receptors are abundant in the CNS, where their physiological role is to mediate fast inhibitory neurotransmission. In insects, this inhibitory transmission plays a crucial role in olfactory information processing. In an effort to understand the nature and properties of the ionotropic receptors involved in these processes in the honeybee Apis mellifera, we performed a pharmacological and molecular characterization of GABA-gated channels in the primary olfactory neuropile of the honeybee brain—the antennal lobe (AL)—using whole cell patch-clamp recordings coupled with single-cell RT-PCR. Application of GABA onto AL cells at −110 mV elicited fast inward currents, demonstrating the existence of ionotropic GABA-gated chloride channels. Molecular analysis of the GABA-responding cells revealed that both subunits RDL and LCCH3 were expressed out of the three orthologs of Drosophila melanogaster GABA-receptor subunits encoded within the honeybee genome (RDL, resistant to dieldrin; GRD, GABA/glycine-like receptor of Drosophila ; LCCH3, ligand-gated chloride channel homologue 3), opening the door to possible homo- and/or heteromeric associations. The resulting receptors were activated by insect GABA-receptor agonists muscimol and CACA and blocked by antagonists fipronil, dieldrin, and picrotoxin, but not bicuculline, displaying a typical RDL-like pharmacology. Interestingly, increasing the intracellular calcium concentration potentiated GABA-elicited currents, suggesting a modulating effect of calcium on GABA receptors possibly through phosphorylation processes that remain to be determined. These results indicate that adult honeybee AL cells express typical RDL-like GABA receptors whose properties support a major role in synaptic inhibitory transmission during olfactory information processing.

The effects of glycine and GABA on isolated horizontal cells from the salamander retina

1991 ◽  
Vol 66 (6) ◽  
pp. 2002-2013 ◽  
Author(s):  
T. A. Gilbertson ◽  
S. Borges ◽  
M. Wilson
Keyword(s):  
Horizontal Cell ◽  
Horizontal Cells ◽  
Gamma Aminobutyric Acid ◽  
Light Responses ◽  
Whole Cell Patch Clamp ◽  
Synaptic Interactions ◽  
Outward Currents ◽  
Na Currents ◽  
Inward Currents ◽  
Kinetics Of

1. Horizontal cells, identified by their morphology, were isolated from the salamander retina and examined in whole cell patch clamp. 2. All cells showed large outward currents activating positive to about -50 mV, and a minority of cells showed fast, tetrodotoxin-suppressible Na+ currents. Slow inward currents that might shape the light responses were never observed. 3. All cells showed conductance increases to both gamma-aminobutyric acid (GABA) and glycine that were completely blocked by bicuculline and strychnine, respectively. No cross-blocking by these antagonists was observed. Partial replacements of Cl- with large, impermeant anions indicated that both GABA- and glycine-evoked currents were carried by Cl- ions. 4. Responses to both GABA and glycine desensitized strongly with time constants of approximately 2 s. 5. Responses to glutamate were not enhanced by glycine. Similarly, responses to GABA were not enhanced by glutamate. 6. GABA-mediated synaptic interactions between horizontal cells may account for the changes in the kinetics of horizontal cell light responses seen when glycine is applied to the intact retina.

Patch-clamp recording in myenteric neurons of guinea pig small intestine

1992 ◽  
Vol 262 (6) ◽  
pp. G1074-G1078 ◽  
Author(s):  
L. V. Baidan ◽  
A. V. Zholos ◽  
M. F. Shuba ◽  
J. D. Wood
Keyword(s):  
Small Intestine ◽  
Patch Clamp ◽  
Guinea Pig ◽  
Calcium Currents ◽  
Delayed Rectifier ◽  
Patch Clamp Recording ◽  
Myenteric Neurons ◽  
Delayed Rectifier Current ◽  
Outward Currents ◽  
Current Clamp Mode

The results of our research established the feasibility of applying patch-clamp methods in the study of the cellular neurophysiology of myenteric neurons enzymatically dissociated from adult guinea pig small intestine. Recording in current-clamp mode revealed two populations of neurons. One population discharged repetitively during depolarizing current pulses and displayed anodal-break excitation reminiscent of S/type 1 myenteric neurons. In the second population, spike discharge was limited to one or two spikes at the onset of depolarizing pulses and was similar to the behavior of AH/type 2 neurons. Recording in voltage-clamp mode revealed a complex of overlapping inward and outward whole cell currents. Fast and slow components of inward current were interpreted as sodium and calcium currents, respectively. Outward currents were blocked by cesium and consisted of components with properties of delayed rectifier current and A-type potassium current.

Segment-specific effects of FMRFamide on membrane properties of heart interneurons in the leech

1995 ◽  
Vol 74 (4) ◽  
pp. 1485-1497 ◽  
Author(s):  
J. Schmidt ◽  
S. Gramoll ◽  
R. L. Calabrese
Keyword(s):  
Outward Current ◽  
Membrane Conductance ◽  
Membrane Properties ◽  
Inward Current ◽  
Specific Effects ◽  
Outward Currents ◽  
Voltage Dependent ◽  
Inward Currents ◽  
K Current ◽  
Conductance Increase

1. The effects of Phe-Met-Arg-Phe (FMRF)amide (10(-6) M) on membrane properties of heart interneurons in the third, fourth, and fifth segmental ganglia [HN(3), HN(4), and HN(5) cells, respectively] of the leech were studied using discontinuous current-clamp and single-electrode voltage-clamp techniques. FMRFamide was focally applied onto the soma of the cell under investigation. 2. Application of FMRFamide depolarized HN(3) and HN(4) cells by evoking an inward current. These responses were subject to pronounced desensitization. The inward currents evoked by application of FMRFamide were associated with an increase in membrane conductance and appeared to be voltage dependent. Currents were enhanced at more depolarized potentials. 3. The responsiveness of the HN(3) and HN(4) cells was not affected when the Ca2+ concentration in the bath saline was reduced from normal (1.8 mM) to 0.1 mM. The depolarizing response on application of FMRFamide was blocked when Co2+ was substituted for Ca2+. 4. HN(3) and HN(4) cells did not respond to FMRFamide application in Na(+)-free solution. Inward currents were largely reduced when bath saline with 30% of the normal Na+ concentration was used. When Li+ was substituted for Na+ in the saline, application of FMRFamide still evoked depolarizing responses in HN(3) and HN(4) cells. 5. We conclude that focal application of FMRFamide onto the somata of HN(3) and HN(4) cells evokes a voltage-dependent inward current, carried largely by Na+. 6. Focal application of FMRFamide onto somata of HN(5) cells hyperpolarized these cells by activating a voltage-dependent outward current. 7. HN(5) cells were loaded with Cl- until inhibitory postsynaptic potentials carried by Cl- reversed. Cl(-)-loaded cells still responded with a hyperpolarization when FMRFamide was applied onto their somata. Therefore the outward current evoked by FMRFamide appears to be mediated by a K+ conductance increase. 8. Application of FMRFamide onto the somata of HN(5) cells enhanced outward currents that were evoked by depolarizing voltage steps from a holding potential of -45 mV. 9. We conclude that the hyperpolarizing response of HN(5) cells to focal application of FMRFamide onto their somata is the result of an up-regulation of a voltage-dependent K+ current.

Serotonergic modulation of neuronal activity in rat midbrain periaqueductal gray

2013 ◽  
Vol 109 (11) ◽  
pp. 2712-2719 ◽  
Author(s):  
Hyo-Jin Jeong ◽  
Karen Lam ◽  
Vanessa A. Mitchell ◽  
Christopher W. Vaughan
Keyword(s):  
Brain Slices ◽  
Periaqueductal Gray ◽  
Membrane Excitability ◽  
Inhibitory Effects ◽  
Whole Cell Patch Clamp ◽  
Outward Currents ◽  
Selective Ligands ◽  
Inward Currents ◽  
Subtype Selective ◽  
Serotonergic Modulation

Serotonin (5-HT) modulates pain and anxiety from within the midbrain periaqueductal gray (PAG). In the present study, the effects of 5-HT- and 5-HT1/2 subtype-selective ligands on rat PAG neurons were examined using whole cell patch-clamp recordings in brain slices. In voltage clamp, 5-HT produced outward and inward currents in distinct subpopulations of neurons that varied throughout different subregions of the PAG. The 5-HT1A agonist R(+)-8-OH-DPAT (1 μM) produced outward currents in subpopulations of PAG neurons. By contrast, sumatriptan (1 μM) and other 5-HT1B, -D, and -F subtype agonists had little or no postsynaptic activity. The 5-HT2A/C agonists DOI (3 μM) and TCB-2 (1 μM) produced inward currents in subpopulations of PAG neurons, and DOI enhanced evoked inhibitory postsynaptic currents via a presynaptic mechanism. In current clamp, both R(+)-8-OH-DPAT and sumatriptan produced an excitatory increase in evoked mixed postsynaptic potentials (PSPs). In addition, R(+)-8-OH-DPAT, but not sumatriptan, directly hyperpolarized PAG neurons. By contrast, the 5-HT2 agonist DOI depolarized subpopulations of neurons and produced an inhibitory decrease in evoked mixed PSPs. These findings indicate that 5-HT1A and 5-HT1B/D ligands have partly overlapping inhibitory effects on membrane excitability and synaptic transmission within the PAG, which are functionally opposed by 5-HT2A/C actions in specific PAG subregions.

Characterization of Outward Currents Induced by 5-HT in Neurons of Rat Dorsolateral Septal Nucleus

2001 ◽  
Vol 85 (4) ◽  
pp. 1453-1460 ◽  
Author(s):  
Kei Yamada ◽  
Hiroshi Hasuo ◽  
Masaru Ishimatsu ◽  
Takashi Akasu
Keyword(s):  
Protein Kinase ◽  
G Protein ◽  
Reversal Potential ◽  
Membrane Conductance ◽  
Inward Rectifier ◽  
Inward Rectification ◽  
Septal Nucleus ◽  
Whole Cell Patch Clamp ◽  
Outward Currents ◽  
Artificial Cerebrospinal Fluid

Properties of the 5-hydroxytryptamine (5-HT)-induced current ( I 5-HT) were examined in neurons of rat dorsolateral septal nucleus (DLSN) by using whole cell patch-clamp techniques. I 5-HT was associated with an increase in the membrane conductance of DLSN neurons. The reversal potential of I 5-HT was −93 ± 6 (SE) mV ( n = 7) in the artificial cerebrospinal fluid (ACSF) and was changed by 54 mV per decade change in the external K+ concentration, indicating that I 5-HT is carried exclusively by K+. Voltage dependency of the K+ conductance underlying I 5-HT was investigated by using current-voltage relationship. I 5-HTshowed a linear I-V relation in 63%, inward rectification in 21%, and outward rectification in 16% of DLSN neurons. (±)-8-Hydroxy-dipropylaminotetralin hydrobromide (30 μM), a selective 5-HT1A receptor agonist, also produced outward currents with three types of voltage dependency. Ba2+ (100 μM) blocked the inward rectifier I 5-HT but not the outward rectifier I 5-HT. In I 5-HT with linear I-Vrelation, blockade of the inward rectifier K+current by Ba2+ (100 μM) unmasked the outward rectifier current in DLSN neurons. These results suggest that I 5-HT with linear I-Vrelation is the sum of inward rectifier and outward rectifier K+ currents in DLSN neurons. Intracellular application of guanosine-5′- O-(3-thiotriphosphate) (300 μM) and guanosine-5′- O-(2-thiodiphosphate) (5 mM), blockers of G protein, irreversibly depressed I 5-HT. Protein kinase C (PKC) 19-36 (20 μM), a specific PKC inhibitor, depressed the outward rectifier I 5-HT but not the inward rectifier I 5-HT. I 5-HT was depressed by N-ethylmaleimide, which uncouples the G-protein-coupled receptor from pertussis-toxin-sensitive G proteins. H-89 (10 μM) and adenosine 3′,5′-cyclic monophosphothioate Rp-isomer (300 μM), protein kinase A inhibitors, did not depress I 5-HT. Phorbol 12-myristate 13-acetate (10 μM), an activator of PKC, produced an outward rectifying K+ current. These results suggest that both 5-HT-induced inward and outward rectifying currents are mediated by a G protein and that PKC is probably involved in the transduction pathway of the outward rectifying I 5-HT in DLSN neurons.

scholarly journals Distinct Subtypes of Cholecystokinin (CCK)-Containing Interneurons of the Basolateral Amygdala Identified Using a CCK Promoter-Specific Lentivirus

2009 ◽  
Vol 101 (3) ◽  
pp. 1494-1506 ◽  
Author(s):  
Aaron M. Jasnow ◽  
Kerry J. Ressler ◽  
Sayamwong E. Hammack ◽  
Jasmeer P. Chhatwal ◽  
Donald G. Rainnie
Keyword(s):  
Basolateral Amygdala ◽  
Function Analysis ◽  
Hierarchical Cluster ◽  
Heterogeneous Population ◽  
Membrane Properties ◽  
Patch Clamp Recording ◽  
Whole Cell Patch Clamp ◽  
Physiological Properties ◽  
Current Clamp Mode

The basolateral amygdala (BLA) is critical for the formation of emotional memories. Little is known about the physiological properties of BLA interneurons, which can be divided into four subtypes based on their immunocytochemical profiles. Cholecystokinin (CCK) interneurons play critical roles in feedforward inhibition and behavioral fear responses. Evidence suggests that interneurons within a subgroup can display heterogeneous physiological properties. However, little is known about the physiological properties of CCK interneurons in the BLA and/or whether they represent a homogeneous or heterogeneous population. To address this question, we generated a lentivirus-expressing GFP under the control of the CCK promoter to identify CCK neurons in vivo. We combined this with whole cell patch-clamp recording techniques to examine the physiological properties of CCK-containing interneurons of the rat BLA. Here, we describe the physiological properties of 57 cells recorded in current-clamp mode; we used hierarchical cluster and discriminant function analysis to demonstrate that CCK interneurons can be segregated into three distinct subtypes (I, II, III) based on their passive and active membrane properties. Additionally, Type II neurons could be further separated into adapting and nonadapting types based on their rates of spike frequency adaptation. These data suggest that CCK interneurons of the BLA are a heterogeneous population and may be functionally distinct subpopulations that differentially contribute to the processing of emotionally salient stimuli.

Acid-sensing ion channels contribute to the increase in vesicular release from SH-SY5Y cells stimulated by extracellular protons

2012 ◽  
Vol 303 (4) ◽  
pp. C376-C384 ◽  
Author(s):  
Qiu-Ju Xiong ◽  
Zhuang-Li Hu ◽  
Peng-Fei Wu ◽  
Lan Ni ◽  
Zhi-Fang Deng ◽  
...  
Keyword(s):  
Ion Channels ◽  
Neurotransmitter Release ◽  
Neuronal Cell ◽  
Channel Blockers ◽  
Patch Clamp Recording ◽  
Human Neuroblastoma ◽  
Whole Cell Patch Clamp ◽  
Acid Sensing Ion Channels ◽  
Vesicular Release ◽  
Inward Currents

Acid-sensing ion channels (ASICs) have been reported to play a role in the neuronal dopamine pathway, but the exact role in neurotransmitter release remains elusive. Human neuroblastoma SH-SY5Y is a dopaminergic neuronal cell line, which can release monoamine neurotransmitters. In this study, the expression of ASICs was identified in SH-SY5Y cells to further explore the role of ASICs in vesicular release stimulated by acid. We gathered evidence that ASICs could be detected in SH-SY5Y cells. In whole cell patch-clamp recording, a rapid decrease in extracellular pH evoked inward currents, which were reversibly inhibited by 100 μM amiloride. The currents were pH dependent, with a pH of half-maximal activation (pH0.5) of 6.01 ± 0.04. Furthermore, in calcium imaging and FM 1-43 dye labeling, it was shown that extracellular protons increased intracellular calcium levels and vesicular release in SH-SY5Y cells, which was attenuated by PcTx1 and amiloride. Interestingly, N-type calcium channel blockers inhibited the vesicular release induced by acidification. In conclusion, ASICs are functionally expressed in SH-SY5Y cells and involved in vesicular release stimulated by acidification. N-type calcium channels may be involved in the increase in vesicular release induced by acid. Our results provide a preliminary study on ASICs in SH-SY5Y cells and neurotransmitter release, which helps to further investigate the relationship between ASICs and dopaminergic neurons.

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