Ibotenic acid: its excitatory and possibly sedative actions in cerebral cortex

1981 ◽  
Vol 59 (9) ◽  
pp. 1025-1030 ◽  
Author(s):  
E. Puil
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Cortical Neurons ◽  
Ibotenic Acid ◽  
Membrane Resistance ◽  
Synaptic Activity ◽  
Repetitive Firing ◽  
Cortical Surface ◽  
Repeated Applications ◽  
Stimulation Of

A slowly developing excitation with afterdischarge is produced by microiontophoretic application of the racemate of ibotenic acid to pericruciate cortical neurons of cats which had been "decerebrated" by forebrain isolation during brief anesthesia. The extracellularly observed excitation tended to accumulate with repeated applications. In many instances the ibotenate excitation was blocked with local administrations of H2-receptor antagonists which also "antagonized" glutamate excitation. With intracellular recording, similar iontophoretic applications of ibotenate were observed to produce longlasting depolarizations and repetitive firing which was not maintained despite suprathreshoid depolarization. These actions were not accompanied by consistent changes in membrane resistance. A most striking feature of ibotenate action was to increase spontaneous synaptic activity and the amplitude of EPSP's evoked by electrical stimulation of the cortical surface or n. ventralis lateralis of the thalamus. These new data are strongly suggestive of presynaptic actions of ibotenate in the cerebral cortex although postsynaptic actions of this isoxazole presumably are also important to an understanding of how ibotenate produces its inebriating and hypnotic effects in animals and man.

Fastigial nucleus-mediated respiratory responses depend on the medullary gigantocellular nucleus

2001 ◽  
Vol 91 (4) ◽  
pp. 1713-1722 ◽  
Author(s):  
Fadi Xu ◽  
Tongrong Zhou ◽  
Tonya Gibson ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Ibotenic Acid ◽  
Major Effect ◽  
Fastigial Nucleus ◽  
Respiratory Response ◽  
The Right ◽  
Spontaneously Breathing ◽  
Respiratory Responses ◽  
Gigantocellular Nucleus ◽  
Stimulation Of

Electrical stimulation of the rostral fastigial nucleus (FNr) alters respiration via activation of local neurons. We hypothesized that this FNr-mediated respiratory response was dependent on the integrity of the nucleus gigantocellularis of the medulla (NGC). Electrical stimulation of the FNr in 15 anesthetized and tracheotomized spontaneously breathing rats significantly altered ventilation by 35.2 ± 11.0% ( P < 0.01) with the major effect being excitatory (78%). This respiratory response did not significantly differ from control after lesions of the NGC via bilateral microinjection of kainic or ibotenic acid (4.5 ± 1.9%; P > 0.05) but persisted in sham controls. Eight other rats, in which horseradish peroxidase (HRP) solution was previously microinjected into the left NGC, served as nonstimulation controls or were exposed to either 15-min repeated electrical stimulation of the right FNr or hypercapnia for 90 min. Histochemical and immunocytochemical data showed that the right FNr contained clustered HRP-labeled neurons, most of which were double labeled with c-Fos immunoreactivity in both electrically and CO2-stimulated rats. We conclude that the NGC receives monosynaptic FNr inputs and is required for fully expressing FNr-mediated respiratory responses.

HIGH-FREQUENCY MONOPOLAR ELECTRICAL STIMULATION OF THE RAT CEREBRAL CORTEX

Neurosurgery ◽  
2007 ◽  
Vol 60 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Masahiro Oinuma ◽  
Kyouichi Suzuki ◽  
Takashi Honda ◽  
Masato Matsumoto ◽  
Tatsuya Sasaki ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
High Frequency ◽  
Rat Cerebral Cortex ◽  
Stimulation Of

scholarly journals Repetitive firing occurring during synchronized electrical stimulation of the heart

1966 ◽  
Vol 51 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Agustin Castellanos ◽  
Louis Lemberg ◽  
James R. Jude ◽  
Barouh V. Berkovits
Keyword(s):  
Electrical Stimulation ◽  
Repetitive Firing ◽  
Stimulation Of

Characterization of Synaptic Conductances and Integrative Properties During Electrically Induced EEG-Activated States in Neocortical Neurons In Vivo

2005 ◽  
Vol 94 (4) ◽  
pp. 2805-2821 ◽  
Author(s):  
Michael Rudolph ◽  
Joe Guillaume Pelletier ◽  
Denis Paré ◽  
Alain Destexhe
Keyword(s):  
Cortical Neurons ◽  
Computational Models ◽  
Input Resistance ◽  
Synaptic Activity ◽  
Intracellular Recordings ◽  
Neocortical Neurons ◽  
Up States ◽  
Conductance State ◽  
Stimulation Of

The activation of the electroencephalogram (EEG) is paralleled with an increase in the firing rate of cortical neurons, but little is known concerning the conductance state of their membrane and its impact on their integrative properties. Here, we combined in vivo intracellular recordings with computational models to investigate EEG-activated states induced by stimulation of the brain stem ascending arousal system. Electrical stimulation of the pedonculopontine tegmental (PPT) nucleus produced long-lasting (≈20 s) periods of desynchronized EEG activity similar to the EEG of awake animals. Intracellularly, PPT stimulation locked the membrane into a depolarized state, similar to the up-states seen during deep anesthesia. During these EEG-activated states, however, the input resistance was higher than that during up-states. Conductance measurements were performed using different methods, which all indicate that EEG-activated states were associated with a synaptic activity dominated by inhibitory conductances. These results were confirmed by computational models of reconstructed pyramidal neurons constrained by the corresponding intracellular recordings. These models indicate that, during EEG-activated states, neocortical neurons are in a high-conductance state consistent with a stochastic integrative mode. The amplitude and timing of somatic excitatory postsynaptic potentials were nearly independent of the position of the synapses in dendrites, suggesting that EEG-activated states are compatible with coding paradigms involving the precise timing of synaptic events.

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