gamma-Aminobutyric acid-induced response in acutely isolated nucleus solitarii neurons of the rat

1991 ◽  
Vol 260 (4) ◽  
pp. C745-C749 ◽  
Author(s):  
T. Nakagawa ◽  
M. Wakamori ◽  
T. Shirasaki ◽  
T. Nakaye ◽  
N. Akaike
Keyword(s):  
Response Curve ◽  
Aminobutyric Acid ◽  
Equilibrium Potential ◽  
Induced Response ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Voltage Dependent ◽  
Concentration Response Curve

The gamma-aminobutyric acid (GABA)-induced macroscopic Cl- current (ICl) was investigated in acutely isolated nucleus tractus solitarii (NTS) neurons by a conventional patch-clamp technique combined with a rapid drug application method. The GABA- and muscimol-induced ICl increased in a concentration-dependent manner. The reversal potentials were close to the Cl- equilibrium potential. Pentobarbital sodium (PB) itself elicited a current. Bicuculline (BIC), strychnine (STR), picrotoxin, benzylpenicillin (PCG), Cd2+, and Zn2+ suppressed the GABA response in a concentration-dependent manner. Both BIC and STR shifted the concentration-response curve for GABA response to the right, whereas PCG suppressed the maximum response without affecting the threshold, indicating that BIC and STR antagonized competitively and PCG noncompetitively. The inhibitory action of PCG on GABA response was in a highly voltage-dependent manner. PB shifted the concentration-response curve for GABA response to the left. The augmentatory effect of PB was voltage dependent.

gamma-Aminobutyric acid-induced response in rat dissociated paratracheal ganglion cells

1992 ◽  
Vol 67 (5) ◽  
pp. 1367-1374 ◽  
Author(s):  
S. Itabashi ◽  
K. Aibara ◽  
H. Sasaki ◽  
N. Akaike
Keyword(s):  
Response Curve ◽  
Ganglion Cells ◽  
Aminobutyric Acid ◽  
Equilibrium Potential ◽  
Induced Response ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Concentration Response Curve

1. The pharmacologic properties of gamma-aminobutyric acid (GABA)-induced Cl- current (ICl) were studied in the paratracheal ganglion cells freshly dissociated from 7- to 10-day-old rat trachea in a whole-cell recording mode by the use of a conventional patch-clamp technique. 2. GABA- and muscimol-induced currents increased sigmoidally in a concentration-dependent manner, and both currents reversed at approximately -3 mV, which was close to the Cl- equilibrium potential (ECl). 3. Strychnine (STR) at low concentration and bicuculline (BIC) inhibited GABA response competitively, whereas STR at the higher concentrations, benzylpenicillin (PCG), or picrotoxin (PTX) inhibited noncompetitively. Inhibition of GABA response by PCG but not other antagonists was voltage dependent, indicating that PCG acts as a Cl- channel blocker. 4. The concentration-response curve of pentobarbital sodium (PB)-induced ICl was bell shaped. At concentrations higher than 10(-3) M, both the peak and plateau currents decreased, and a transient "hump" current appeared immediately after washing out PB. In the presence of PB, the concentration-response curve of GABA shifted toward left without changing the maximum response. 5. Although diazepam (DZP) at concentration used did not induce a response, it potentiated the GABA response in a concentration-dependent manner between 10(-8) and 10(-6) M. DZP also caused a parallel shift toward left in the concentration-response curve of GABA. 6. PB or DZP further enhanced the GABA response in the presence of the other agent. 7. It is concluded that the properties of GABAA receptors in the paratracheal ganglion cells are essentially similar to those reported in other preparations.

Allosteric modulation of GABAA receptors in acutely dissociated neurons of the suprachiasmatic nucleus

1996 ◽  
Vol 270 (6) ◽  
pp. C1726-C1734 ◽  
Author(s):  
M. Shimura ◽  
N. Harata ◽  
M. Tamai ◽  
N. Akaike
Keyword(s):  
Gabaa Receptor ◽  
Suprachiasmatic Nucleus ◽  
Gabaa Receptors ◽  
Response Curve ◽  
Equilibrium Potential ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Gabaa Receptor Antagonist ◽  
Inward Currents ◽  
Concentration Response Curve

The gamma-aminobutyric acid (GABA)-induced response was investigated in acutely dissociated suprachiasmatic nucleus (SCN) neurons of 11- to 14-day-old rats, under the voltage-clamp condition of nystatin-perforated patch recording. At a holding potential of -40 mV, application of GABA induced inward currents in a concentration-dependent manner. Pentobarbital and 5 beta-pregnan-3 alpha-ol-20-one (pregnanolone) similarly induced inward currents. GABA-induced inward currents were suppressed in a concentration-dependent manner by pretreating neurons with a GABAA receptor antagonist, bicuculline. Bicuculline (3 x 10(-6) M) shifted the concentration-response curve of GABA to the left in a competitive manner. Reversal potential of the GABA response (EGABA) was -3.4 +/- 0.7 mV, close to the theoretical Cl- equilibrium potential of -4.1 mV. Pretreating SCN neurons with diazepam, pentobarbital, and pregnanolone enhanced the 3 x 10(-6) M GABA response. Diazepam (3 x 10(-8) M), pentobarbital (3 x 10(-5) M), and pregnanolone (10(-7) M) shifted the concentration-response curve of GABA to the left without changing the maximal amplitude of GABA responses. EGABA in the presence of diazepam, pentobarbital, or pregnanolone was the same as that in their absence. These results show that the GABA response in acutely dissociated SCN neurons is mediated by the GABAA receptor. Because the GABAA receptor of SCN neurons is allosterically augmented by diazepam, pentobarbital, and pregnanolone, similarly as in other regions of the central nervous system, the present study opens up ways to functionally modulate the GABAA receptors in SCN.

Quinolones and fenbufen interact with GABAA receptor in dissociated hippocampal cells of rat

1991 ◽  
Vol 66 (2) ◽  
pp. 497-504 ◽  
Author(s):  
N. Akaike ◽  
T. Shirasaki ◽  
T. Yakushiji
Keyword(s):  
Gabaa Receptor ◽  
Pyramidal Neurons ◽  
Equilibrium Potential ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Inflammatory Agent ◽  
Quinolone Antibiotics ◽  
Anti Inflammatory

1. Interaction of quinolone antibiotics and the anti-inflammatory agent fenbufen with the gamma-aminobutyric acid-A (GABAA) receptor-chloride channel complex in pyramidal neurons freshly dissociated from the hippocampal CA1 region of the rats was investigated in whole-cell mode, using the patch-clamp technique under voltage-clamp conditions. 2. Quinolones in clinical doses had no effects on the GABA-gated Cl- current (ICl) but slightly suppressed the response at concentrations greater than 10(-5) M. A metabolite of fenbufen, 4-biphenylacetic acid (BPA), also had little effect on the GABA response at therapeutic concentrations. 3. Coadministration of one of quinolones and BPA suppressed the GABA-gated ICl with increase in each of them in a concentration-dependent manner, and there was a parallel shift of the concentration-response curve for GABA to the right but with no effect on the maximum response, thereby indicating a competitive antagonism. The inhibitory potency of antibiotics in combination with BPA was in the order of norfloxacin much greater than enoxacin greater than cyprofloxacin greater than pipemidic acid much greater than ofloxacin greater than cinoxacin = piromidic acid = nalidixic acid = 0. 4. Norfloxacin and BPA, administered simultaneously, also strongly suppressed pentobarbital sodium (PB)-gated ICl, but they did not act on benzodiazepine (BZP) receptors. 5. Both GABA- and PB-induced ICls reversed at the Cl- equilibrium potential (ECl). In the presence of BPA, the quinolone-induced inhibition of GABA-gated ICls showed no voltage dependence. 6. It was concluded that, in the presence of an anti-inflammatory agent, the quinolone antibiotics decrease the affinity of GABAA receptors, the result being induction of epileptogenic neurotoxicities.

Cholinergic stimulation modulates negative inotropic effect of cocaine on ferret ventricular myocardium

1996 ◽  
Vol 270 (2) ◽  
pp. H678-H684
Author(s):  
L. Miao ◽  
Z. Qiu ◽  
J. P. Morgan
Keyword(s):  
Response Curve ◽  
Negative Inotropic Effect ◽  
Ventricular Myocardium ◽  
Inotropic Effect ◽  
Dependent Manner ◽  
Cholinergic Stimulation ◽  
Concentration Dependent Manner ◽  
Cell Shortening ◽  
Inotropic State ◽  
Concentration Response Curve

We tested the hypothesis that the negative inotropic effect (NIE) of cocaine is mediated, at least in part, by cholinergic stimulation and can be correlated with the degree of adenosine 3',5'-cyclic monophosphate (cAMP) dependency of the inotropic state. Cardiac myocytes were isolated from left ventricles of ferrets and loaded with the fluorescent Ca2+ indicator indo 1. Cells were placed in physiological solution containing 2.0 mM Ca2+ and stimulated at 0.5 Hz and 30 degrees C. Cocaine decreased peak cell shortening and peak intracellular Ca2+ in a concentration-dependent manner (10(-8)-10(-4) M). The concentration-response curve of cocaine was shifted significantly downward compared with those of lidocaine and procaine in the same range of concentrations. Atropine (10(-6) M) shifted the concentration-response curve of cocaine, but not those of lidocaine and procaine, rightward, with a pA2 value (7.66) similar to that obtained with carbachol (7.99). With prior addition of isoproterenol (ISO, 10(-8) M) or increased Ca2+ (4.0 mM) to increase cell shortening to the same degree (approximately 60%), cocaine and carbachol decreased contractility to a significantly greater extent in ISO-stimulated myocytes. To clarify whether these treatments changed responsiveness of the contractile elements to Ca2+, the effect of 2,3-butanedione monoxime, an agent that interferes with the interaction of myosin and actin, was tested with previous addition of ISO or increased Ca2+, and no differential effect occurred. Therefore, we postulate that 1) the NIE of cocaine on myocytes is caused by decreased Ca2+ availability; 2) this effect is due to specific stimulation of cholinergic receptors in addition to other direct myocardial (probably local anesthetic) effects; and 3) the NIE correlates with the level of cAMP dependence of the inotropic state.

Direct block of cloned hKv1.5 channel by cytochalasins, actin-disrupting agents

2005 ◽  
Vol 289 (2) ◽  
pp. C425-C436 ◽  
Author(s):  
Bok Hee Choi ◽  
Jung-Ah Park ◽  
Kyung-Ryoul Kim ◽  
Ggot-Im Lee ◽  
Yong-Tae Lee ◽  
...  
Keyword(s):  
Actin Filament ◽  
Cytochalasin B ◽  
Delayed Rectifier ◽  
Dependent Manner ◽  
Patch Clamp Technique ◽  
Independent Manner ◽  
Concentration Dependent Manner ◽  
Voltage Range ◽  
Whole Cell Patch Clamp ◽  
Voltage Dependent

The action of cytochalasins, actin-disrupting agents on human Kv1.5 channel (hKv1.5) stably expressed in Ltk− cells was investigated using the whole cell patch-clamp technique. Cytochalasin B inhibited hKv1.5 currents rapidly and reversibly at +60 mV in a concentration-dependent manner with an IC50 of 4.2 μM. Cytochalasin A, which has a structure very similar to cytochalasin B, inhibited hKv1.5 (IC50 of 1.4 μM at +60 mV). Pretreatment with other actin filament disruptors cytochalasin D and cytochalasin J, and an actin filament stabilizing agent phalloidin had no effect on the cytochalasin B-induced inhibition of hKv1.5 currents. Cytochalasin B accelerated the decay rate of inactivation for the hKv1.5 currents. Cytochalasin B-induced inhibition of the hKv1.5 channels was voltage dependent with a steep increase over the voltage range of the channel's opening. However, the inhibition exhibited voltage independence over the voltage range in which channels are fully activated. Cytochalasin B produced no significant effect on the steady-state activation or inactivation curves. The rate constants for association and dissociation of cytochalasin B were 3.7 μM/s and 7.5 s−1, respectively. Cytochalasin B produced a use-dependent inhibition of hKv1.5 current that was consistent with the slow recovery from inactivation in the presence of the drug. Cytochalasin B (10 μM) also inhibited an ultrarapid delayed rectifier K+ current ( IK,ur) in human atrial myocytes. These results indicate that cytochalasin B primarily blocks activated hKv1.5 channels and endogenous IK,ur in a cytoskeleton-independent manner as an open-channel blocker.

scholarly journals Potentiation of NO-dependent activation of soluble guanylyl cyclase by 5-nitroisatin and antiviral preparatation arbidol

2013 ◽  
Vol 59 (3) ◽  
pp. 295-304
Author(s):  
I.S. Severina ◽  
A.Yu. Schegolev ◽  
A.E. Medvedev
Keyword(s):  
Guanylyl Cyclase ◽  
Response Curve ◽  
Physiological Activity ◽  
Soluble Guanylyl Cyclase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Leftward Shift ◽  
Wide Range ◽  
Concentration Response Curve ◽  
Synergistic Increase

Isatin (indole-dione) is an endogenous indole that exibits a wide range of biological and physiological activity. The influence of isatin derivatives 5-nitroisatin and arbidol (an antiviral preparatation) on spermine NONO-induced activation of human platelet soluble guanylyl cyclase was investigated. 5-nitroistnin and arbidol had no effect on basal activity, but synergistically increased in a concentration-dependent manner the spermine NONO-induced activation of this enzyme. 5-Nitroisatin and arbidol, like YC-1, sensitized guanylyl cyclase towards nitric oxide (NO) and produced a leftward shift of the spermine NONO concentration response curve. At the same time both compounds used did not influence the activation of guanylyl cyclase by YC-1 and did not change the synergistic increase of spermine NONO-induced activation of soluble guanylyl cyclase in the presence of YC-1. This suggests that 5-nitroisanin and arbidol did not compete with YC-1. Addition of isatin did not change the synergistic increase in the spermine NONO-induced guanylyl cyclase activation by 5-nitroisatin and arbidol and did not influence a leftward shift of spermine NONO concentration response curve produced by these compounds. These data suggest lack of competitive interaction between isatin and both its derivatives used.

scholarly journals Effects of suplatast tosilate on acutely dissociated sensory and paratracheal ganglia neurons

2016 ◽  
Vol 311 (4) ◽  
pp. L770-L778 ◽  
Author(s):  
Jian-Rong Zhou ◽  
Tetsuya Shirasaki ◽  
Fumio Soeda ◽  
Kazuo Takahama
Keyword(s):  
Acetylcholine Release ◽  
Inhibitory Concentration ◽  
Lower Airway ◽  
Dependent Manner ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Pathological Conditions ◽  
Voltage Dependent ◽  
Pretreatment Time ◽  
Postganglionic Nerve

In this study, we investigated the effects of suplatast on acutely dissociated single neurons of sensory and paratracheal ganglia using a patch-clamp technique. Suplatast had little effect on various responses caused by capsaicin, acid, bradykinin, serotonin, and adenosine 5′-triphosphate in rat sensory neurons. Suplatast, even at 10−3 M, also did not induce any current at various membrane potentials in rat and guinea pig paratracheal ganglia neurons. Furthermore, acetylcholine- and bradykinin-induced depolarizations were not affected by suplatast. On the other hand, in rat paratracheal ganglia neurons, 10−5 M nicotine-induced current were inhibited by suplatast in a concentration-dependent manner with a 50% inhibitory concentration of 9.86 × 10−5 M. The effect was noncompetitive and voltage dependent. Furthermore, the effect was use independent and not affected by the pretreatment time of suplatast. The results suggested that suplatast may inhibit neurotransmission at the paratracheal ganglia via the inhibition of nicotinic current. Thus suplatast may attenuate cough production through the improvement of pathological conditions of the lower airway via suppressed acetylcholine release from the postganglionic nerve terminal.

Expression of 5-HT3 receptors in PC12 cells treated with NGF and 8-Br-cAMP

1992 ◽  
Vol 67 (4) ◽  
pp. 812-819 ◽  
Author(s):  
K. Furukawa ◽  
N. Akaike ◽  
H. Onodera ◽  
K. Kogure
Keyword(s):  
Pc12 Cells ◽  
Reversal Potential ◽  
Inward Rectification ◽  
Inactivation Kinetics ◽  
Induced Response ◽  
Dependent Manner ◽  
Induced Current ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Inward Current

1. To determine the functional development of neurons, we applied nerve growth factor (NGF) or 8-bromo-cyclic-adenosine monophosphate (8-Br-cAMP) to PC12 cells and recorded the 5-hydroxytryptamine (5-HT)-induced response by the use of a patch-clamp technique. 2. Cultured PC12 cells expressed 5-HT-sensitive receptors, which are almost absent in untreated cells, in the continuous presence of NGF or 8-Br-cAMP for a period of 10 days. 3. Activation of the receptors by 5-HT produced a transient inward current. In a K(+)-free solution, the reversal potential (E5-HT) of I5-HT was +10.3 mV, and the current-voltage (I-V) relation showed inward rectification at positive potentials. 4. The permeability ratio for monovalent cations was Na+:Li+:K+:Rb+:Cs+ = 1:1.19:0.89:0.94:0.91, indicating that a 5-HT-induced current is passing through the ligand-gated large cation channel. 5. 2-Methyl-5-HT, a specific 5-HT3 agonist, induced a similar inward current, even though the current amplitude was smaller and the activation and inactivation kinetics were slower than those of 5-HT. 6. ICS-205-930, a specific 5-HT3 antagonist, inhibited the 5-HT-induced current in a concentration-dependent manner with a noncompetitive inhibition profile. Spiperone, a 5-HT1 and 5-HT2 families antagonist, and ketanserine, 5-HT2 family antagonist, did not affect the 5-HT-induced response. 7. The time to peak (tp) as well as fast and slow time constants (tau if and tau is) decreased with increasing 5-HT concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of glucose deprivation on NMDA-induced current and intracellular Ca2+ in rat substantia nigra neurons

1996 ◽  
Vol 75 (2) ◽  
pp. 740-749 ◽  
Author(s):  
Y. Nakashima ◽  
H. Ishibashi ◽  
N. Harata ◽  
N. Akaike
Keyword(s):  
Substantia Nigra ◽  
Outward Current ◽  
Glucose Deprivation ◽  
Equilibrium Potential ◽  
Dependent Manner ◽  
Induced Current ◽  
Patch Clamp Technique ◽  
Concentration Dependent Manner ◽  
Inward Current ◽  
Rat Substantia Nigra

1. The effects of glucose deprivation on N-methyl-D-asparate (NMDA)-induced current (INMDA) and the intracellular free Ca2+ concentration ([Ca2+]i) in the acutely dissociated rat substantia nigra neurons were investigated using the nystatin-perforated patch-clamp technique under voltage clamp and the microfluometry with a fluorescent probe, Indo-1. 2. Application of NMDA induced a peak and a successive steady-state inward current, and an outward current immediately after washout at a holding potential of -40 mV. The amplitudes of the three current components of INMDA were increased by increasing the concentrations of NMDA with half-maximum concentrations (EC50s) of 1.1 x 10(-4) M, 1.2 x 10(-4) M, and 1.6 x 10(-4) M, respectively. 3. The reversal potentials of the peak inward and outward currents were -4 +/- 3 (SE) mV and -76 +/- 2 mV, respectively. The latter was close to the theoretical K+ equilibrium potential (-82 mV). 4. The outward current was potentiated by increase in extracellular Ca2+ concentration and was blocked by Cs+ internal solution and suppressed by 5 x 10(-3) M tetraethylammonium chloride and 10(-7) M charybdotoxin, indicating that it was Ca(2+)-activated K+ current. 5. Application of NMDA increased [Ca2+]i in a concentration-dependent manner with an EC50 of 3.9 x 10(-5) M. 6. Depriving the external solution of glucose induced a slowly developing outward current and increased the basal level of [Ca2+]i. It also prolonged the NMDA-induced outward current without affecting the peak inward current, and prolonged the NMDA-induced increase in [Ca2+]i without changing the peak [Ca2+]i. 7. These findings suggest that the deprivation of glucose did not affect the NMDA-induced influx of Ca2+ into the cells, but it inhibited Ca2+ clearance by affecting the efflux of Ca2+ to the extracellular space, reuptake into the intracellular Ca2+ stores, and/or active extrusion from intracellular stores.

gamma-Aminobutyric acid stimulates acid secretion from the isolated guinea pig stomach

1987 ◽  
Vol 253 (5) ◽  
pp. G601-G606
Author(s):  
L. H. Tsai ◽  
K. Taniyama ◽  
C. Tanaka
Keyword(s):  
Guinea Pig ◽  
Acid Secretion ◽  
Cholinergic Neurons ◽  
Aminobutyric Acid ◽  
Dependent Manner ◽  
Gamma Aminobutyric Acid ◽  
Concentration Dependent Manner ◽  
High Concentrations ◽  
Guinea Pig Stomach ◽  
Spontaneous Secretion

gamma-Aminobutyric acid (GABA) content was measured, and the effect of GABA on acid secretion was studied using the everted preparation of isolated guinea pig stomachs. GABA contents in the mucosa layer and the remaining layer were 20-24 nmol/g tissue and 34-42 nmol/g tissue, respectively. GABA at 10(-6) to 3 X 10(-5) M induced acid secretion, and the maximum secretion was obtained at 3 X 10(-5) M, that is approximately 1.6-fold of the spontaneous secretion and approximately half of the amount secreted by histamine at 3 X 10(-4) M. The GABA-induced acid secretion was inhibited by bicuculline, scopolamine, pirenzepine, proglumide, and tetrodotoxin, but not by cimetidine. Muscimol (3 X 10 to 10(-5) M), but not baclofen, induced acid secretion in a concentration-dependent manner. The responses to GABA and muscimol were antagonized by bicuculline. Scopolamine and tetrodotoxin completely inhibited the acid secretion induced by low concentrations of GABA and muscimol and to some extent the response induced by high concentrations of muscimol. All these results indicate that GABA induces acid secretion via the A type of GABA receptor, probably located mainly on the cholinergic neurons and partially on the nonneuronal cells in the guinea pig stomach.

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