Bicuculline- and Phaclofen-Resistant Hyperpolarizations Evoked by Glutamate Applications to Stratum Lacunosum-Moleculare in CA1 Pyramidal Cells of the Rat Hippocampus In Vitro

1990 ◽  
Vol 2 (11) ◽  
pp. 993-1002 ◽  
Author(s):  
Sylvain Williams ◽  
Jean-Claude Lacaille
Keyword(s):  
Pyramidal Cells ◽  
Rat Hippocampus ◽  
Ca1 Pyramidal Cells ◽  
Stratum Lacunosum Moleculare

scholarly journals Synaptic GABAA Activation Inhibits AMPA-Kainate Receptor–Mediated Bursting in the Newborn (P0–P2) Rat Hippocampus

2000 ◽  
Vol 83 (1) ◽  
pp. 359-366 ◽  
Author(s):  
Karri Lamsa ◽  
J. Matias Palva ◽  
Eva Ruusuvuori ◽  
Kai Kaila ◽  
Tomi Taira
Keyword(s):  
Pyramidal Neurons ◽  
Field Potential ◽  
Pyramidal Cells ◽  
Neuronal Population ◽  
Excitatory Input ◽  
Calcium Oscillations ◽  
Rat Hippocampus ◽  
Network Activity ◽  
Ca1 Pyramidal Cells

The mechanisms of synaptic transmission in the rat hippocampus at birth are assumed to be fundamentally different from those found in the adult. It has been reported that in the CA3-CA1 pyramidal cells a conversion of “silent” glutamatergic synapses to conductive α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) synapses starts gradually after P2. Further, GABA via its depolarizing action seems to give rise to grossly synchronous yet slow calcium oscillations. Therefore, GABA is generally thought to have a purely excitatory rather than an inhibitory role during the first postnatal week. In the present study field potential recordings and gramicidin perforated and whole cell clamp techniques as well as K+-selective microelectrodes were used to examine the relative contributions of AMPA and GABAA receptors to network activity of CA3-CA1 pyramidal cells in the newborn rat hippocampus. As early as postnatal day( P 0–P2), highly coherent spontaneous firing of CA3 pyramidal cells was seen in vitro. Negative-going extracellular spikes confined to periodic bursts (interval 16 ± 3 s) consisting of 2.9 ± 0.1 spikes were observed in stratum pyramidale. The spikes were accompanied by AMPA-R–mediated postsynaptic currents (PSCs) in simultaneously recorded pyramidal neurons (7.6 ± 3.0 unitary currents per burst). In CA1 pyramidal cells synchronous discharging of CA3 circuitry produced a barrage of AMPA currents at >20 Hz frequencies, thus demonstrating a transfer of the fast CA3 network activity to CA1 area. Despite its depolarizing action, GABAA-R–mediated transmission appeared to exert inhibition in the CA3 pyramidal cell population. The GABAA-R antagonist bicuculline hypersynchronized the output of glutamatergic CA3 circuitry and increased the network-driven excitatory input to the pyramidal neurons, whereas the GABAA-R agonist muscimol (100 nM) did the opposite. However, the occurrence of unitary GABAA-R currents was increased after muscimol application from 0.66 ± 0.16 s−1 to 1.43 ± 0.29 s−1. It was concluded that AMPA synapses are critical in the generation of spontaneous high-frequency bursts in CA3 as well as in CA3-CA1 transmission as early as P0–P2 in rat hippocampus. Concurrently, although GABAA-R–mediated depolarization may excite hippocampal interneurons, in CA3 pyramidal neurons it can restrain excitatory inputs and limit the size of the activated neuronal population.

scholarly journals Location of Sialoglycoconjugates Containing the Siaα2–3Gal and Siaα2–6Gal Groups in the Rat Hippocampus and the Effect of Aging on Their Expression

2001 ◽  
Vol 49 (10) ◽  
pp. 1311-1319 ◽  
Author(s):  
Yuji Sato ◽  
Yoshihiro Akimoto ◽  
Hayato Kawakami ◽  
Hiroshi Hirano ◽  
Tamao Endo
Keyword(s):  
Electron Microscopy ◽  
Plasma Membranes ◽  
Pyramidal Cells ◽  
Staining Intensity ◽  
Rat Hippocampus ◽  
Maackia Amurensis ◽  
Ca1 Region ◽  
Old Rats ◽  
Maackia Amurensis Lectin ◽  
Stratum Lacunosum Moleculare

The histochemical distribution of sialoglycoconjugates in the CA1 region in the hippocampus formation of 9-week-old rats and 30-month-old rats was examined using electron microscopy in combination with two lectins, Maackia amurensis lectin, specific for Siaα2–3Gal, and Sambucus sieboldiana agglutinin, specific for Siaα2–6Gal. Each lectin stained the plasma membranes of pyramidal cells, indicating that the Siaα2–3Gal and Siaα2–6Gal groups were expressed on their plasma membranes. These lectins also bound to synapses in the stratum lacunosum moleculare. The staining intensity of the lectins in the synapses in these layers was downregulated in the 30-month-old rats. These results indicated that both the Siaα2–3Gal and Siaα2–6Gal groups are expressed on these synapses and that the expression of these sialyl linkages decreases in the aged brain.

Autoradiographic Localization of Opioid and Spirodecanone Receptors in the Gerbil Hippocampus as Compared with the Rat Hippocampus

1988 ◽  
Vol 8 (4) ◽  
pp. 568-574 ◽  
Author(s):  
Hiroshi Onodera ◽  
Kyuya Kogure
Keyword(s):  
Opioid Receptor ◽  
Binding Sites ◽  
Cellular Localization ◽  
Neuronal Damage ◽  
Pyramidal Cells ◽  
Rat Hippocampus ◽  
High Concentration ◽  
Receptor Sites ◽  
Ca3 Neurons

Opioid ([3H]naloxone) and spirodecanone ([3H]spiperone) binding sites in the hippocampus were visualized in the Mongolian gerbil and in the rat using in vitro autoradiography. In the hippocampus, marked differences were noted in the stratum (sr.) pyramidale of the CA1 subfield where opioid and spirodecanone (assayed in the presence of mianserin and sulpiride) binding activities were very low in gerbils, but high in rats. Gerbils exhibited a high concentration of [3H]naloxone binding sites in the sr. pyramidale of the CA3 subfield, as observed in the rat. In addition, the gerbil has a very high opioid receptor density in the hilar region and in the sr. moleculare of the dentate gyrus. The cellular localization of opioid and spirodecanone receptor sites was studied in the rat hippocampus using selective neuronal damage to CA1 and CA3 neurons by means of ischemia and kainic acid treatment, respectively. The results suggest that the gerbil differs from the rat with respect to the characteristic pyramidal cells (spirodecanone binding site) and interneurons (opioid receptor) in the CA1 subfield of the hippocampus. Distinct localization of opioid and spirodecanone receptors in the gerbil provides a good model with which to investigate the electrophysiological and biochemical roles of opioid peptides and butyrophenone spirodecanone drugs.

Barbiturate protection against hypoxic neuronal damage in vitro

1986 ◽  
Vol 65 (2) ◽  
pp. 230-232 ◽  
Author(s):  
Peter G. Aitken ◽  
Steven J. Schiff
Keyword(s):  
Neuronal Damage ◽  
Pyramidal Cells ◽  
Perfusion Medium ◽  
Tissue Slices ◽  
Content Type ◽  
Ca1 Pyramidal Cells ◽  
Hippocampal Tissue ◽  
Barbiturate Protection ◽  
Fine Print

✓ Hippocampal tissue slices in vitro were exposed to periods of hypoxia of different durations. Addition of pentobarbital to the perfusion medium significantly increased the duration of hypoxia that was survived by CA1 pyramidal cells.

Cannabinoid receptor activation in CA1 pyramidal cells in adult rat hippocampus

2000 ◽  
Vol 863 (1-2) ◽  
pp. 120-131 ◽  
Author(s):  
M.Todd Kirby ◽  
Robert E Hampson ◽  
Sam A Deadwyler
Keyword(s):  
Cannabinoid Receptor ◽  
Pyramidal Cells ◽  
Receptor Activation ◽  
Rat Hippocampus ◽  
Adult Rat ◽  
Ca1 Pyramidal Cells

scholarly journals A Classification Method to Distinguish Cell-Specific Responses Elicited by Current Pulses in Hippocampal CA1 Pyramidal Cells

2008 ◽  
Vol 20 (6) ◽  
pp. 1512-1536 ◽  
Author(s):  
José Ambros-Ingerson ◽  
Lawrence M. Grover ◽  
William R. Holmes
Keyword(s):  
Distance Measure ◽  
Network Models ◽  
Pyramidal Cells ◽  
Spike Timing ◽  
Voltage Gradient ◽  
Neural Function ◽  
Ca1 Pyramidal Cells ◽  
Current Pulses ◽  
Point Distance

The suprathreshold electrophysiological responses of pyramidal cells have been grouped into large classes such as bursting and spiking. However, it is not known whether, within a class, response variability ranges uniformly across all cells or whether each cell has a unique and consistent profile that can be differentiated. A major difficulty when comparing suprathreshold responses is that slight variations in spike timing in otherwise very similar traces render traditional metrics ineffective. To address these issues, we developed a novel distance measure based on fiducial points to quantify the similarity among traces with trains of action potentials and applied it together with classification techniques to a set of in vitro patch clamp recordings from CA1 pyramidal cells. We tested if responses to repeated current stimulation of a given cell would cluster together yet remain distinct from those of other cells. We found that depolarizing and hyperpolarizing current pulses elicited responses in each cell that clustered and were systematically distinguishable from responses in other cells. The fiducial-point distance measure was more effective than other methods based on spike times and voltage-gradient phase planes. Depolarizing traces were more reliably differentiated than hyperpolarizing traces, and combining both scores was even more effective. These results suggest that each CA1 pyramidal cell has unique properties that can be detected and quantified with methods discussed here. This uniqueness may be due to slight variations in morphology or membrane channel densities and kinetics, or to large, coordinated variations in these elements. Ascertaining the actual sources and their degree of variability is important when constructing network models of neural function to ensure that key mechanisms are robust in the face of variations within these ranges. The analytical tools presented here can assist in constructing detailed cell models to match experimental records to elucidate the sources of electrophysiological variability in neurons.

Intrinsic Ca2+-dependent theta oscillations in apical dendrites of hippocampal CA1 pyramidal cells in vitro

2014 ◽  
Vol 112 (3) ◽  
pp. 631-643 ◽  
Author(s):  
Allan Kjeldsen Hansen ◽  
Steen Nedergaard ◽  
Mogens Andreasen
Keyword(s):  
Frequency Band ◽  
Pyramidal Cells ◽  
Sine Wave ◽  
Detectable Effect ◽  
Ca1 Pyramidal Cells ◽  
Theta Frequency ◽  
Voltage Dependent ◽  
Oscillatory Mechanism ◽  
Apical Dendrites

Behavior-associated theta-frequency oscillation in the hippocampal network involves a patterned activation of place cells in the CA1, which can be accounted for by a somatic-dendritic interference model predicting the existence of an intrinsic dendritic oscillator. Here we describe an intrinsic oscillatory mechanism in apical dendrites of in vitro CA1 pyramidal cells, which is induced by suprathreshold depolarization and consists of rhythmic firing of slow spikes in the theta-frequency band. The incidence of slow spiking (29%) increased to 78% and 100% in the presence of the β-adrenergic agonist isoproterenol (2 μM) or 4-aminopyridine (2 mM), respectively. Prior depolarization facilitated the induction of slow spiking. Applied electrical field polarization revealed a distal dendritic origin of slow spikes. The oscillations were largely insensitive to tetrodotoxin, but blocked by nimodipine (10 μM), indicating that they depend on activation of L-type Ca2+ channels. Antagonists of T-, R-, N-, and P/Q-type Ca2+ channels had no detectable effect. The slow spike dimension and frequency was sensitive to 4-aminopyridine (0.1–2 mM) and TEA (10 mM), suggesting the contribution from voltage-dependent K+ channels to the oscillation mechanism. α-Dendrotoxin (10 μM), stromatoxin (2 μM), iberiotoxin (0.2 μM), apamin (0.5 μM), linorpidine (30 μM), and ZD7288 (20 μM) were without effect. Oscillations induced by sine-wave current injection or theta-burst synaptic stimulation were voltage-dependently attenuated by nimodipine, indicating an amplifying function of L-type Ca2+ channels on imposed signals. These results show that the apical dendrites have intrinsic oscillatory properties capable of generating rhythmic voltage fluctuations in the theta-frequency band.

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