Effect of acute lead treatmant on in vivo hippocampal population spikes in rats

1995 ◽  
Vol 78 ◽  
pp. 64
Author(s):  
A. Papp ◽  
K. Györgyi ◽  
L. Nagymajtényi ◽  
I. Dési
Keyword(s):  
Population Spikes

Serotonin blocks the facilitatory action of muscarinic and nicotinic agents in the hippocampus in vivo

1989 ◽  
Vol 67 (1) ◽  
pp. 47-53 ◽  
Author(s):  
Y. Hong ◽  
K. Krnjević
Keyword(s):  
Inhibitory Action ◽  
Pyramidal Cells ◽  
Inhibitory Effect ◽  
Population Spike ◽  
Rat Hippocampus ◽  
Population Spikes ◽  
Ca1 Region ◽  
Facilitatory Action ◽  
Hippocampal Pyramidal Cells

The inhibitory effect of serotonin, released iontophoretically, on acetylcholine-induced facilitation of population spikes evoked by fimbria–commissural stimulation was studied in the CA1 region of rat hippocampus in vivo. After serotonin was applied for 2.6 ± 0.8 min, acetylcholine's action was inhibited in 39 cases out of 57 (68.4%), by 68.9 ± 23.1%, irrespective of whether serotonin alone increased or reduced the population spike. Spiperone, used as a 5-hydroxytryptamine1A (5-HT1A) antagonist, suppressed the inhibitory action of serotonin in 14 of 21 tests. Serotonin had similar effects on population spike facilitations induced by acetyl-β-methylcholine and dimethylphenylpiperazinium. Thus serotonin, probably acting on 5-HT1A receptors, blocks effectively but indiscriminately all cholinergic facilitations, whether mediated by nicotinic or muscarinic receptors.Key words: serotonin, cholinergic facilitation, hippocampal pyramidal cells, spiperone, muscarinic and nicotinic actions.

scholarly journals Different effects of monophasic pulses and biphasic pulses applied by a bipolar stimulation electrode in the rat hippocampal CA1 region

2021 ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Neuron Activity ◽  
Partial Recovery ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background: Electrical pulse stimulations have been applied in brain for treating certain diseases such as movement disorders. High-frequency stimulations (HFS) of biphasic pulses have been used in clinic stimulations, such as deep brain stimulation (DBS), to minimize the risk of tissue damages caused by the electrical stimulations. However, HFS sequences of monophasic pulses have often been used in animal experiments for studying neuronal responses to the stimulations. It is not clear yet what the differences of the neuronal responses to the HFS of monophasic pulses from the HFS of biphasic pulses are. Methods: To investigate the neuronal responses to the two types of pulses, orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of biphasic and monophasic pulses (1-min) were delivered by bipolar electrodes respectively to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in-vivo. Evoked population spikes of CA1 pyramidal neurons to the HFSs were recorded in the CA1 region. In addition, single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFSs to evaluate the baseline and the recovery of neuronal activity, respectively. Results: Spreading depression (SD) appeared during sequences of 200 Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200 Hz biphasic O-HFS (0/6). A preceding burst of population spikes appeared before the SD waveforms. Then, the SD propagated slowly, silenced neuronal firing temporarily and resulted in partial recovery of orthodromically-evoked population spikes (OPS) after the end of O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic or biphasic pulses (0/5 and 0/6, respectively), neither during the A-HFS of 200 Hz pulses (0/9). The antidromically-evoked population spikes (APS) after 200 Hz biphasic A-HFS recovered to baseline level within ~2 min. However, the APS only recovered partially after the 200 Hz A-HFS of monophasic pulses.Conclusions: The O-HFS with a higher frequency of monophasic pulses can induce the abnormal neuron activity of SD and the A-HFS of monophasic pulses can cause a persisting attenuation of neuronal excitability, indicating neuronal damages caused by monophasic stimulations in brain tissues. The results provide guidance for proper stimulation protocols in clinic and animal experiments.

scholarly journals Different Effects of Monophasic Pulses and Biphasic Pulses Applied by a Bipolar Stimulation Electrode in the Rat Hippocampal CA1 Region

2020 ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Brain Diseases ◽  
Neuron Activity ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background: Deep brain stimulation (DBS) has been successfully used for treating certain brain diseases such as movement disorders. High-frequency stimulations (HFS) of charge-balanced biphasic pulses have been used in clinic DBS to minimize the risk of tissue damages caused by the electrical stimulations, while HFS sequences of monophasic pulses have been used in animal experiments to investigate DBS therapy. However, it is not clear whether HFS sequences of monophasic pulses could induce abnormal neuronal responses different from biphasic pulses. Thus, the present study investigates the differences of neuronal responses to HFS of monophasic pulses and biphasic pulses.Methods: Orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of the two types of pulses (with a 1-min duration) were delivered by bipolar electrodes to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in-vivo, respectively. Responses of CA1 pyramidal neurons to the stimulations were recorded in the CA1 region. Single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFS to evoke population spikes for evaluating the baseline and the recovery of neuronal activity. Results: Spreading depression (SD) appeared during sequences of 200 Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200 Hz biphasic O-HFS (0/6). The potential waveform of SD was accompanied by a preceding burst of population spikes, propagated slowly, silenced neuronal firing temporarily and resulted in a non-recovery of orthodromically-evoked population spikes (OPS) after the O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic and biphasic pulses (0/5 and 0/6, respectively) nor during the A-HFS of 200 Hz pulses (0/9). However, the antidromically-evoked population spikes (APS) only recovered partially after the 200 Hz A-HFS of monophasic pulses.Conclusions: The O-HFS with a high enough frequency of monophasic pulses may induce the abnormal neuron activity of SD instantaneously, which may be used as a biomarker to warn the damages caused by improper stimulations in brain tissues.

scholarly journals Different effects of monophasic pulses and biphasic pulses applied by a bipolar stimulation electrode in the rat hippocampal CA1 region

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Yue Yuan ◽  
Lvpiao Zheng ◽  
Zhouyan Feng ◽  
Gangsheng Yang
Keyword(s):  
Animal Experiments ◽  
Neuronal Firing ◽  
Neuron Activity ◽  
Partial Recovery ◽  
Neuronal Responses ◽  
Population Spikes ◽  
Ca1 Region ◽  
Hippocampal Ca1 Region ◽  
Hippocampal Ca1

Abstract Background Electrical pulse stimulations have been applied in brain for treating certain diseases such as movement disorders. High-frequency stimulations (HFS) of biphasic pulses have been used in clinic stimulations, such as deep brain stimulation (DBS), to minimize the risk of tissue damages caused by the electrical stimulations. However, HFS sequences of monophasic pulses have often been used in animal experiments for studying neuronal responses to the stimulations. It is not clear yet what the differences of the neuronal responses to the HFS of monophasic pulses from the HFS of biphasic pulses are. Methods To investigate the neuronal responses to the two types of pulses, orthodromic-HFS (O-HFS) and antidromic-HFS (A-HFS) of biphasic and monophasic pulses (1-min) were delivered by bipolar electrodes, respectively, to the Schaffer collaterals (i.e., afferent fibers) and the alveus fibers (i.e., efferent fibers) of the rat hippocampal CA1 region in vivo. Evoked population spikes of CA1 pyramidal neurons to the HFSs were recorded in the CA1 region. In addition, single pulses of antidromic- and orthodromic-test stimuli were applied before and after HFSs to evaluate the baseline and the recovery of neuronal activity, respectively. Results Spreading depression (SD) appeared during sequences of 200-Hz monophasic O-HFS with a high incidence (4/5), but did not appear during corresponding 200-Hz biphasic O-HFS (0/6). A preceding burst of population spikes appeared before the SD waveforms. Then, the SD propagated slowly, silenced neuronal firing temporarily and resulted in partial recovery of orthodromically evoked population spikes (OPS) after the end of O-HFS. No SD events appeared during the O-HFS with a lower frequency of 100 Hz of monophasic or biphasic pulses (0/5 and 0/6, respectively), neither during the A-HFS of 200-Hz pulses (0/9). The antidromically evoked population spikes (APS) after 200-Hz biphasic A-HFS recovered to baseline level within ~ 2 min. However, the APS only recovered partially after the 200-Hz A-HFS of monophasic pulses. Conclusions The O-HFS with a higher frequency of monophasic pulses can induce the abnormal neuron activity of SD and the A-HFS of monophasic pulses can cause a persisting attenuation of neuronal excitability, indicating neuronal damages caused by monophasic stimulations in brain tissues. The results provide guidance for proper stimulation protocols in clinic and animal experiments.

scholarly journals Apical and Basal Orthodromic Population Spikes in Hippocampal CA1 In Vivo Show Different Origins and Patterns of Propagation

2001 ◽  
Vol 86 (5) ◽  
pp. 2435-2444 ◽  
Author(s):  
Fabian Kloosterman ◽  
Pascal Peloquin ◽  
L. Stan Leung
Keyword(s):  
Cell Body ◽  
Initial Segment ◽  
Current Source ◽  
Population Spike ◽  
Population Spikes ◽  
Stratum Oriens ◽  
Basal Dendrites ◽  
Apical Dendrites ◽  
Stimulation Of

There is controversy concerning whether orthodromic action potentials originate from the apical or basal dendrites of CA1 pyramidal cells in vivo. The participation of the dendrites in the initialization and propagation of population spikes in CA1 of urethan-anesthetized rats in vivo was studied using simultaneously recorded field potentials and current source density (CSD) analysis. CSD analysis revealed that the antidromic population spike, evoked by stimulation of the alveus, invaded in succession, the axon initial segment (stratum oriens), cell body and ∼200 μm of the proximal apical dendrites. Excitation of the basal dendrites of CA1, following stimulation of CA3 stratum oriens, evoked an orthodromic spike that started near the cell body or initial segment and then propagated ∼200 μm into the proximal apical dendrites. In contrast, the population spike that followed excitation of the apical dendrites of CA1 initiated at the proximal apical dendrites, 50–100 μm distal to the cell body layer, and then propagated centripetally to the cell body and the proximal basal dendrites. A late apical dendritic spike may arise in the mid-apical dendrites (250–300 μm from the cell layer) and propagated distally. The origin or the pattern of propagation of each population spike type was similar for near-threshold to supramaximal stimulus intensities. In summary, population spikes following apical dendritic and basal dendritic excitation in vivo appeared to originate from different locations. Apical dendritic excitation evoked a population spike that initiated in the proximal apical dendrites while basal dendritic excitation evoked a spike that started near the initial segment or cell body. An original finding of this study is the propagation of the population spike from basal to apical dendrites in vivo or vice versa. This backpropagation from one dendritic tree to the other may play an important role in the synaptic plasticity among a network of CA3 to CA1 neurons.

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