Minimal Stimulation IVF

Despite the major role of excitatory cortico-cortical connections in mediating neocortical activities, little is known about these synapses at the cellular level. Here we have characterized the synaptic properties of long-range excitatory-to-excitatory contacts between visually identified layer V pyramidal neurons of agranular frontal cortex in callosally connected neocortical slices from postnatal day 13 to 21( P13–21) rats. Midline stimulation of the corpus callosum with a minimal stimulation paradigm evoked inward excitatory postsynaptic currents (EPSCs) with an averaged peak amplitude of 56.5 ± 5 pA under conditions of whole cell voltage clamp at −70 mV. EPSCs had fixed latencies from stimulus onset and could follow stimulus trains (1–20 Hz) without changes in kinetic properties. Bath application of 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) abolished these responses completely, indicating that they were mediated by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPARs). Evoked responses were isolated in picrotoxin to yield purely excitatory PSCs, and a low concentration of NBQX (0.1 μM) was used to partially block AMPARs and prevent epileptiform activity in the tissue. Depolarization of the recorded pyramidal neurons revealed a late, slowly decaying component that reversed at ∼0 mV and was blocked by d-2-amino-5-phosphonovaleric acid. Thus AMPA and N-methyl-d-aspartate receptors (NMDARs) coexist at callosal synapses and are likely to be activated monosynaptically. The peak amplitudes and decay time constants for EPSCs evoked using minimal stimulation (±40 mV) were similar to spontaneously occurring sEPSCs. Typical conductances associated with AMPA and NMDAR-mediated components, deduced from their respective current-voltage ( I-V) relationships, were 525 ± 168 and 966 ± 281 pS, respectively. AMPAR-mediated responses showed age-dependent changes in the rectification properties of their I-V relationships. While I-Vs from animals > P15 were linear, those in the younger (< P16) age group were inwardly rectifying. Although Ca2+ permeability in AMPARs can be correlated with inward rectification, outside-out somatic patches from younger animals were characterized by Ca2+-impermeable receptors, suggesting that somatic receptors might be functionally different from those located at synapses. While the biophysical properties of AMPAR components of callosally-evoked EPSCs were similar to those evoked by stimulation of local excitatory connections, the NMDA component displayed input-specific differences. NMDAR-mediated responses for local inputs were activated at more hyperpolarized holding potentials in contrast with those evoked by callosal stimulation. Paired stimuli used to assay presynaptic release properties showed paired-pulse depression (PPD) in animals < P16, which converted to facilitation (PPF) in older animals, suggesting a developmental transition from low probability of transmitter release to high P r at these synapses and/or alterations in the properties of the underlying postsynaptic receptors. Physiologic properties of neocortical e-e connections are thus input specific and subject to developmental changes in their postsynaptic receptors.

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Pathway-Specific Targeting of GABAA Receptor Subtypes to Somatic and Dendritic Synapses in the Central Amygdala

Journal of Neurophysiology ◽

10.1152/jn.2001.86.2.717 ◽

2001 ◽

Vol 86 (2) ◽

pp. 717-723 ◽

Cited By ~ 41

Author(s):

Andrew J. Delaney ◽

Pankaj Sah

Keyword(s):

Gaba Receptors ◽

Large Amplitude ◽

Gaba Receptor ◽

Small Amplitude ◽

Inhibitory Synapses ◽

Receptor Subtypes ◽

Central Amygdala ◽

Low Concentrations ◽

Gabaa Receptor Subtypes ◽

Minimal Stimulation

Neurons in the central amygdala express two distinct types of ionotropic GABA receptor. One is the classical GABAA receptor that is blocked by low concentrations of bicuculline and positively modulated by benzodiazepines. The other is a novel type of ionotropic GABA receptor that is less sensitive to bicuculline but blocked by the GABAC receptor antagonist (1,2,5,6-tetrohydropyridine-4-yl) methylphosphinic acid (TPMPA) and by benzodiazepines. In this study, we examine the distribution of these two receptor types. Recordings of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) showed a wide variation in amplitude. Most events had amplitudes of <50 pA, but a small minority had amplitudes >100 pA. Large-amplitude events also had rise times faster than small-amplitude events. Large-amplitude events were fully blocked by 10 μM bicuculline but unaffected by TPMPA. Small amplitude events were partially blocked by both bicuculline and TPMPA. Focal application of hypertonic sucrose to the soma evoked large-amplitude mIPSCs, whereas focal dendritic application of sucrose evoked small-amplitude mIPSCs. Thus inhibitory synapses on the dendrites of neurons in the central amygdala express both types of GABA receptor, but somatic synapses expressed purely GABAA receptors. Minimal stimulation revealed that inhibitory inputs arising from the laterally located intercalated cells innervate dendritic synapses, whereas inhibitory inputs of medial origin innervated somatic inhibitory synapses. These results show that different types of ionotropic GABA receptors are targeted to spatially and functionally distinct synapses. Thus benzodiazepines will have different modulatory effects on different inhibitory pathways in the central amygdala.

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Heterogeneity in Use-Dependent Depression of Inhibitory Postsynaptic Potentials in the Rat Neostriatum In Vitro

Journal of Neurophysiology ◽

10.1152/jn.1997.77.1.427 ◽

1997 ◽

Vol 77 (1) ◽

pp. 427-434 ◽

Cited By ~ 9

Author(s):

Gabriele Radnikow ◽

Jutta Rohrbacher ◽

Ulrich Misgeld

Keyword(s):

Aminobutyric Acid ◽

Medium Spiny Neurons ◽

Stimulus Interval ◽

Postsynaptic Potentials ◽

Inhibitory Postsynaptic Potentials ◽

Spiny Neurons ◽

Neostriatal Slices ◽

Minimal Stimulation ◽

Paired Pulse Depression

Radnikow, Gabriele, Jutta Rohrbacher, and Ulrich Misgeld. Heterogeneity in use-dependent depression of inhibitory postsynaptic potentials in the rat neostriatum in vitro. J. Neurophysiol. 77: 427–434, 1997. “Minimal stimulation” was applied to evoke responses in an “all-or-none” fashion in presumed medium spiny neurons of rat neostriatal slices in the presence of antagonists for glutamatergic excitation. For comparison, responses were evoked in the same cells by compound stimulation. Bicuculline (30 μM) blocked responses evoked by minimal stimulation, indicating that they were γ-aminobutyric acid-A (GABAA)-receptor-mediated inhibitory postsynaptic potentials (IPSPs), whereas responses evoked by compound stimulation were only reduced in amplitude. Likewise, R(−)baclofen (1–20 μM) blocked IPSPs evoked by minimal stimulation in all but one cell. On the contrary, responses evoked by compound stimulation were always reduced in amplitude but never blocked. Paired-pulse depression (PPD) of averaged responses to minimal and compound stimulation was observed at a stimulus interval of 300 ms. The GABAB receptor antagonist CGP55845A (0.5 μM) had no effect on PPD evoked by compound stimulation but abolished PPD evoked by minimal stimulation. In a second set of experiments, the two stimulation paradigms were used to evoke responses in neostriatal slices continuously bathed in R(−)baclofen (10–20 μM). In R(−)baclofen a strong PPD was evoked by minimal and by compound stimulation. The amplitude of the response to compound stimulation increased on application of CGP55845A (0.5 μM). At the same time, PPD evoked by compound stimulation decreased. On the contrary, IPSP amplitude and PPD evoked by minimal stimulation remained unchanged. We conclude that two types of GABAergic terminals exist in the rat neostriatum, only one of which is regulated by GABAB receptors. However, the other class of terminals, not regulated by GABAB receptors, displays a much more pronounced PPD.

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MINIMAL STIMULATION USING GONADOTROPIN-RELEASING HORMONE ANTAGONIST IS ASSOCIATED WITH HIGHER LIVE BIRTH RATES: A NATIONAL STUDY OF 13,050 CYCLES

Fertility and Sterility ◽

10.1016/j.fertnstert.2020.08.789 ◽

2020 ◽

Vol 114 (3) ◽

pp. e286

Author(s):

Emily G. Hurley ◽

Fangbai Sun ◽

Heping Zhang ◽

Alex J. Polotsky ◽

Julie Sroga Rios

Keyword(s):

Live Birth ◽

Gonadotropin Releasing Hormone ◽

National Study ◽

Birth Rates ◽

Releasing Hormone ◽

Live Birth Rates ◽

Minimal Stimulation

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Minimal stimulation is an excellent option for the “poor responder” to long protocol

Fertility and Sterility ◽

10.1016/j.fertnstert.2013.07.252 ◽

2013 ◽

Vol 100 (3) ◽

pp. S520

Author(s):

E.K. Chun ◽

C. Park ◽

K.R. Kim ◽

H.E. Ryu ◽

C.S. Ryu ◽

...

Keyword(s):

Poor Responder ◽

The Poor ◽

Minimal Stimulation ◽

Long Protocol

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Auditory Thalamocortical Transmission Is Reliable and Temporally Precise

Journal of Neurophysiology ◽

10.1152/jn.00860.2004 ◽

2005 ◽

Vol 94 (3) ◽

pp. 2019-2030 ◽

Cited By ~ 65

Author(s):

Heather J. Rose ◽

Raju Metherate

Keyword(s):

Primary Auditory Cortex ◽

Inhibitory Neurons ◽

Latency Variability ◽

Medial Geniculate ◽

Low Jitter ◽

Fast Spiking ◽

Whole Cell Recordings ◽

Minimal Stimulation ◽

Juvenile Mouse

We have used the auditory thalamocortical slice to characterize thalamocortical transmission in primary auditory cortex (ACx) of the juvenile mouse. “Minimal” stimulation was used to activate medial geniculate neurons during whole cell recordings from regular-spiking (RS cells; mostly pyramidal) and fast-spiking (FS, putative inhibitory) neurons in ACx layers 3 and 4. Excitatory postsynaptic potentials (EPSPs) were considered monosynaptic (thalamocortical) if they met three criteria: low onset latency variability (jitter), little change in latency with increased stimulus intensity, and little change in latency during a high-frequency tetanus. Thalamocortical EPSPs were reliable (probability of postsynaptic responses to stimulation was ∼1.0) as well as temporally precise (low jitter). Both RS and FS neurons received thalamocortical input, but EPSPs in FS cells had faster rise times, shorter latencies to peak amplitude, and shorter durations than EPSPs in RS cells. Thalamocortical EPSPs depressed during repetitive stimulation at rates (2–300 Hz) consistent with thalamic spike rates in vivo, but at stimulation rates ≥40 Hz, EPSPs also summed to activate N-methyl-d-aspartate receptors and trigger long-lasting polysynaptic activity. We conclude that thalamic inputs to excitatory and inhibitory neurons in ACx activate reliable and temporally precise monosynaptic EPSPs that in vivo may contribute to the precise timing of acoustic-evoked responses.

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