Blockade of the late IPSP in rat CA1 hippocampal neurons by 2-hydroxy-saclofen.
Animals; Rats; Action Potentials/drug effects; In Vitro Techniques; GABA-A Receptor Antagonists; Hippocampus/drug effects/*physiology; Baclofen/*analogs & derivatives/pharmacology; Neural Inhibition/*drug effects; Receptors; GABA-A/*physiology
The effects of the GABAB receptor antagonist 2-hydroxy-saclofen were studied using intracellular recording of synaptic potential from CA1 hippocampal neurons.
Lambert N A; Harrison N L; Kerr D I; Ong J; Prager R H; Teyler T J
Neuroscience letters
1989
1989-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0304-3940(89)90803-3" target="_blank" rel="noreferrer noopener">10.1016/0304-3940(89)90803-3</a>
Cholinergic disinhibition in area CA1 of the rat hippocampus is not mediated by receptors located on inhibitory neurons.
2-Amino-5-phosphonovalerate/pharmacology; Action Potentials/drug effects; Adenosine/pharmacology; Animals; Baclofen/pharmacology; Carbachol/pharmacology; Cholinergic/*drug effects; Evoked Potentials/drug effects; GABA-A Receptor Antagonists; Hippocampus/*drug effects; In Vitro Techniques; Membrane Potentials/drug effects; Neurons/*drug effects; Parasympathetic Nervous System/*drug effects; Phorbol Esters/pharmacology; Quinoxalines/pharmacology; Rats; Receptors; Synaptic Transmission/physiology
We studied the effects of carbamylcholine (carbachol; CCh) on monosynaptic inhibitory postsynaptic potentials (IPSPs) evoked in the presence of the excitatory amino acid receptor antagonists 6,7-dinitroquinoxaline-2,3-dione (DNQX) and D,L-2-amino-5-phosphonovalerate (APV). CCh (30 microM) blocked late afterhyperpolarizations but did not depress GABAA receptor-mediated fast monosynaptic IPSPs or GABAB receptor-mediated late monosynaptic IPSPs. In the presence of CCh the GABAB receptor agonist (+/- )-baclofen (2 microM) reversibly hyperpolarized pyramidal neurons and depressed monosynaptic IPSPs as under control conditions. Phorbol-12,13-diacetate (PDAc; 10 microM) increased fast and depressed late monosynaptic IPSPs, and prevented depression of IPSPs by baclofen. These results suggest that cholinergic disinhibition in area CA1 of the hippocampus results from decreased synaptic excitation of inhibitory neurons.
Lambert N A; Teyler T J
European journal of pharmacology
1991
1991-10
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0014-2999(91)90801-v" target="_blank" rel="noreferrer noopener">10.1016/0014-2999(91)90801-v</a>
Glycinergic inhibition creates a form of auditory spectral integration in nuclei of the lateral lemniscus.
Acoustic Stimulation; Action Potentials/drug effects; Animals; Auditory Perception/drug effects/*physiology; Bicuculline/pharmacology; Brain Stem/drug effects/*physiology; Chiroptera; GABA Antagonists/pharmacology; GABA-A Receptor Antagonists; GABA-A/metabolism; gamma-Aminobutyric Acid/metabolism; Glycine Agents/pharmacology; Glycine/*physiology; Glycine/antagonists & inhibitors/metabolism; Microelectrodes; Neural Inhibition/drug effects/*physiology; Neurons/drug effects/*physiology; Receptors; Strychnine/pharmacology
For analyses of complex sounds, many neurons integrate information across different spectral elements via suppressive effects that are distant from the neurons' excitatory tuning. In the mustached bat, suppression evoked by sounds within the first sonar harmonic (23-30 kHz) or in the subsonar band (\textless23 kHz) alters responsiveness to the higher best frequencies of many neurons. This study examined features and mechanisms associated with low-frequency (LF) suppression among neurons of the lateral lemniscal nuclei (NLL). We obtained extracellular recordings from neurons in the intermediate and ventral nuclei of the lateral lemniscus, observing different forms of LF suppression related to the two above-cited frequency bands. To understand the mechanisms underlying this suppression in NLL neurons, we examined the roles of glycinergic and GABAergic input through local microiontophoretic application of strychnine, an antagonist to glycine receptors (GlyRs), or bicuculline, an antagonist to gamma-aminobutyric acid type A receptors (GABA(A)Rs). With blockade of GABA(A)Rs, neurons showed an increase in firing rate to best frequency (BF) and/or LF tones but retained LF suppression of BF sounds. For neurons that displayed LF suppression tuned to
Peterson Diana Coomes; Nataraj Kiran; Wenstrup Jeffrey
Journal of neurophysiology
2009
2009-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.00040.2009" target="_blank" rel="noreferrer noopener">10.1152/jn.00040.2009</a>
Hyperpolarizing and depolarizing GABAA receptor-mediated dendritic inhibition in area CA1 of the rat hippocampus.
2-Amino-5-phosphonovalerate/pharmacology; Animals; Bicuculline/analogs & derivatives/pharmacology; Chlorides/pharmacology; Dendrites/drug effects/*physiology; Evoked Potentials/drug effects; GABA-A Receptor Antagonists; GABA-A/drug effects/*physiology; Hippocampus/*physiology; In Vitro Techniques; Kinetics; Mathematics; Membrane Potentials/drug effects; Models; Neurological; Neurons/drug effects/*physiology; Organophosphorus Compounds/pharmacology; Pyramidal Tracts/drug effects/*physiology; Quinoxalines/pharmacology; Rats; Receptors; Synapses/drug effects/physiology
1. gamma-Aminobutyric acidA (GABAA) receptor-mediated inhibition of pyramidal neuron dendrites was studied in area CA1 of the rat hippocampal slice preparation with the use of intracellular and extracellular recording and one-dimensional current source-density (CSD) analysis. 2. Electrical stimulation of Schaffer collateral/commissural fibers evoked monosynaptic excitatory postsynaptic potentials (EPSPs) and population EPSPs, which were followed by biphasic inhibitory postsynaptic potentials (IPSPs). In the presence of the excitatory amino acid receptor antagonists 6,7-dinitroquinoxaline-2,3-dione (DNQX) and D,L-2-amino-5-phosphonovalerate (APV), stimulation in stratum radiatum evoked monosynaptic fast, GABAA and late, GABAB receptor-mediated IPSPs and fast and late positive field potentials recorded in s. radiatum. 3. Fast monosynaptic IPSPs and fast positive field potentials evoked in the presence of DNQX and APV were reversibly abolished by the GABAA receptor antagonist bicuculline methiodide (BMI; 30 microM) and were not changed by the GABAB receptor antagonist
Lambert N A; Borroni A M; Grover L M; Teyler T J
Journal of neurophysiology
1991
1991-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.1991.66.5.1538" target="_blank" rel="noreferrer noopener">10.1152/jn.1991.66.5.1538</a>
Roles of inhibition in complex auditory responses in the inferior colliculus: inhibited combination-sensitive neurons.
Acoustic Stimulation; Action Potentials/drug effects/physiology; Afferent/drug effects/*physiology; Animals; Auditory; Auditory Pathways/drug effects/*physiology; Bicuculline/pharmacology; Brain Stem/drug effects/*physiology; Chiroptera; Electrophysiology; Evoked Potentials; GABA-A Receptor Antagonists; GABA-A/physiology; Glycine/antagonists & inhibitors/physiology; Inferior Colliculi/*physiology; Neural Inhibition/drug effects/*physiology; Neurons; Receptors; Strychnine/pharmacology
We studied the functional properties and underlying neural mechanisms associated with inhibitory combination-sensitive neurons in the mustached bat's inferior colliculus (IC). In these neurons, the excitatory response to best frequency tones was suppressed by lower frequency signals (usually in the range of 12-30 kHz) in a time-dependant manner. Of 143 inhibitory units, the majority (71%) were type I, in which low-frequency sounds evoked inhibition only. In the remainder, however, the low-frequency inhibitory signal also evoked excitation. Of these, excitation preceded the inhibition in type E/I units (16%), whereas in type I/E units (13%), excitation followed the inhibition. Type E/I and I/E units were distinct in the tuning and threshold sensitivity of low-frequency responses, whereas type I units overlapped the other types in these features. In 71 neurons, antagonists to receptors for glycine [strychnine (STRY)] or GABA [bicuculline (BIC)] were applied microiontophoretically. These antagonists failed to eliminate combination-sensitive inhibition in 92% (STRY), 93% (BIC), and 87% (BIC + STRY) of the type I units tested. However, inhibition was reduced in many neurons. Results were similar for type E/I and I/E inhibitory neurons. The results indicate that there are distinct populations of combination-sensitive inhibited neurons in the IC and that these populations are at least partly independent of glycine or GABAA receptors in the IC. We propose that these populations originate in different brain stem auditory nuclei, that they may be modified by interactions within the IC, and that they may perform different spectrotemporal analyses of vocal signals.
Nataraj Kiran; Wenstrup Jeffrey J
Journal of neurophysiology
2006
2006-04
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.01148.2005" target="_blank" rel="noreferrer noopener">10.1152/jn.01148.2005</a>
Spermine depresses NMDA, K/AMPA and GABAA-mediated synaptic transmission in the rat hippocampal slice preparation.
AMPA/antagonists & inhibitors; Animals; Calcium Channels/drug effects; Evoked Potentials/drug effects; Excitatory Amino Acid Antagonists/*pharmacology; GABA-A Receptor Antagonists; Hippocampus/drug effects/*physiology; In Vitro Techniques; N-Methyl-D-Aspartate/antagonists & inhibitors; Rats; Receptors; Spermine/*pharmacology; Synapses/drug effects/*physiology; Synaptic Transmission/*drug effects
The effects of spermine, an endogenous polyamine, were examined in area CA1 of the rat hippocampal slice preparation. Spermine, at low millimolar concentrations, rapidly and potently depressed NMDA and K/AMPA-mediated population EPSPs, and GABA-mediated monosynaptic population IPSPs. These effects contrast with its well-known potentiation of NMDA currents at lower concentrations. Our results raise the possibility that the large intracellular stores of spermine that are released after various neural insults could act as an endogenous neuroprotective mechanism by limiting excessive calcium entry.
DiScenna P G; Ferchmin P A; Eterovic V A; Teyler T J
Brain research
1994
1994-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0006-8993(94)91335-8" target="_blank" rel="noreferrer noopener">10.1016/0006-8993(94)91335-8</a>
The development of GABAB-mediated activity in the rat dentate gyrus.
Animals; Baclofen/analogs & derivatives/pharmacology; Electric Stimulation; Evoked Potentials/drug effects; GABA-A Receptor Antagonists; GABA-A/drug effects/physiology; GABA-B Receptor Antagonists; GABA-B/*metabolism; Hippocampus/*growth & development/*metabolism; In Vitro Techniques; Organophosphorus Compounds/pharmacology; Rats; Receptors
We examined the effects of GABAB receptor activation in the dentate gyrus of hippocampal slices prepared from 6-8-day-old rat pup. Baclofen (0.25-1.0 microM), a GABAB agonist, rapidly and potently disinhibited the developing dentate, similar to its effect in the mature organism. CGP 35348, a GABAB antagonist, quickly reversed the baclofen-induced disinhibition. However, GABAB antagonists did not reverse long-latency (500-1000 ms IPI) paired-pulse depression, suggesting that it is not caused by a late GABAB-mediated IPSP. GABAB-mediated disinhibition of the dentate gyrus can occur by postnatal day 6, providing a powerful mechanism for altering excitability in the developing hippocampus.
DiScenna P G; Nowicky A V; Teyler T J
Brain research. Developmental brain research
1994
1994-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0165-3806(94)90206-2" target="_blank" rel="noreferrer noopener">10.1016/0165-3806(94)90206-2</a>