Spatial Distribution and Subunit Composition of GABAAReceptors in the Inferior Olivary Nucleus

2001 ◽  
Vol 85 (4) ◽  
pp. 1686-1696 ◽  
Author(s):  
Anna Devor ◽  
Jean-Marc Fritschy ◽  
Yosef Yarom
Keyword(s):  
Spatial Distribution ◽  
Reversal Potential ◽  
Subunit Composition ◽  
Inferior Olivary Nucleus ◽  
Receptor Subtypes ◽  
Differential Distribution ◽  
Local Pressure ◽  
Abrupt Decrease ◽  
Somatic Response ◽  
Inferior Olivary

GABAergic inhibitory feedback from the cerebellum onto the inferior olivary (IO) nucleus plays an important role in olivo-cerebellar function. In this study we characterized the physiology, subunit composition, and spatial distribution of γ-aminobutyric acid-A (GABAA) receptors in the IO nucleus. Using brain stem slices, we identified two types of IO neuron response to local pressure application of GABA, depending on the site of application: a slow desensitizing response at the soma and a fast desensitizing response at the dendrites. The dendritic response had a more negative reversal potential than did the somatic response, which confirmed their spatial origin. Both responses showed voltage dependence characterized by an abrupt decrease in conductance at negative potentials. Interestingly, this change in conductance occurred in the range of potentials wherein subthreshold membrane potential oscillations usually occur in IO neurons. Immunostaining IO sections with antibodies for GABAA receptor subunits α1, α2, α3, α5, β2/3, and γ2 and against the postsynaptic anchoring protein gephyrin complemented the electrophysiological observation by showing a differential distribution of GABAA receptor subtypes in IO neurons. A receptor complex containing α2β2/3γ2 subunits is clustered with gephyrin at presumptive synaptic sites, predominantly on distal dendrites. In addition, diffuse α3, β2/3, and γ2 subunit staining on somata and in the neuropil presumably represents extrasynaptic receptors. Combining electrophysiology with immunocytochemistry, we concluded that α2β2/3γ2 synaptic receptors generated the fast desensitizing (dendritic) response at synaptic sites whereas the slow desensitizing (somatic) response was generated by extrasynaptic α3β2/3γ2 receptors.

Drug-induced activation of the inferior olivary nucleus in young rabbits

1985 ◽  
Vol 24 (7) ◽  
pp. 645-654 ◽  
Author(s):  
L.A. Barragan ◽  
N. Delhaye-Bouchaud ◽  
P. Laget
Keyword(s):  
Inferior Olivary Nucleus ◽  
Drug Induced ◽  
Inferior Olivary ◽  
Olivary Nucleus

scholarly journals Inferior Olivary nucleus degeneration does not lessen tremor in essential tremor

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Elan D. Louis ◽  
Daniel Trujillo Diaz ◽  
Sheng-Han Kuo ◽  
Shi-Rui Gan ◽  
Etty P. Cortes ◽  
...  
Keyword(s):  
Essential Tremor ◽  
Inferior Olivary Nucleus ◽  
Inferior Olivary ◽  
Olivary Nucleus

Hyperventilation evoked by activation of the vicinity of the caudal inferior olivary nucleus depends on the fastigial nucleus in anesthetized rats

2008 ◽  
Vol 104 (5) ◽  
pp. 1351-1358 ◽  
Author(s):  
Jianguo Zhuang ◽  
Fadi Xu ◽  
Donald T. Frazier
Keyword(s):  
Electrical Stimulation ◽  
Chemical Activation ◽  
Ibotenic Acid ◽  
Fastigial Nucleus ◽  
Inferior Olivary Nucleus ◽  
Ventilatory Responses ◽  
Respiratory Modulation ◽  
Spontaneously Breathing ◽  
Inferior Olivary ◽  
Olivary Nucleus

Several studies have demonstrated that cerebellar deep nuclei, particularly the rostral fastigial nucleus (FNr), are involved in respiratory modulation. These nuclei receive inputs from the contralateral caudal inferior olivary nuclei of the medulla. The objectives of this study were to determine whether electrical and chemical activation of the vicinity of the caudal inferior olivary nuclei (vIOc) affected respiration and, if true, whether the FNr was involved in the vIOc stimulation-evoked ventilatory responses. Experiments were conducted in 30 anesthetized and spontaneously breathing rats. Our results showed that 1) electrical (25 or 100 μA at 10 or 20 Hz for 10 s) and chemical (1 or 100 mM, 25–50 nl N-methyl-d-aspartate) stimulation of the vIOc augmented ventilation predominantly via increasing tidal volume; 2) the responses to the electrical stimulation were almost eliminated by lesion of the contralateral FNr via microinjection of ibotenic acid; and 3) the respiratory responses to electrical stimulation in the vicinity of the rostral IO were 65–70% smaller compared with that evoked by vIOc stimulation. These findings strongly suggest that vIOc neurons play a significant role in modulation of respiratory activity, largely depending on their projections to the FNr.

Subthreshold oscillations of the membrane potential: a functional synchronizing and timing device

1993 ◽  
Vol 70 (5) ◽  
pp. 2181-2186 ◽  
Author(s):  
I. Lampl ◽  
Y. Yarom
Keyword(s):  
Membrane Potential ◽  
Logic Gate ◽  
Maximum Amplitude ◽  
Sine Wave ◽  
Inferior Olivary Nucleus ◽  
Synaptic Potential ◽  
Synaptic Potentials ◽  
Subthreshold Oscillations ◽  
Inferior Olivary ◽  
Olivary Nucleus

1. Subthreshold membrane potential oscillations have been observed in different types of CNS neurons. In this in vitro study, we examined the possible role of these oscillations by analyzing the responses of neurons from the inferior olivary nucleus to a combined stimulation of sine wave and synaptic potentials. 2. A nonlinear summation of the sine wave and the synaptic potential occurred in olivary neurons; a superlinear summation occurred when the synaptic potential was elicited at the trough of the sine wave or during the rising phase. On the other hand, a less than linear summation occurred when the synaptic potentials were evoked during the falling phase of the wave. 3. Significant changes in the delay of the synaptic responses were observed. As a result of these changes, the maximum amplitude of the response occurred at the peak of the sine wave, regardless of the exact time of stimulation. The output of the neuron was therefore synchronized with the sine wave and depended only partly on the input phase. 4. These data demonstrate that neurons from the inferior olivary nucleus are capable of operating as accurate synchronizing devices. Moreover, by affecting the delay line, they act as a logic gate that ensures that the information will be added to the system only at given times.

Electrotonic Coupling in the Inferior Olivary Nucleus Revealed by Simultaneous Double Patch Recordings

2002 ◽  
Vol 87 (6) ◽  
pp. 3048-3058 ◽  
Author(s):  
Anna Devor ◽  
Yosef Yarom
Keyword(s):  
Coupling Coefficient ◽  
Direct Calculation ◽  
Physiological Data ◽  
Inferior Olivary Nucleus ◽  
Potential Oscillations ◽  
Electrotonic Coupling ◽  
Cell Pair ◽  
Coupling Resistance ◽  
The Difference ◽  
Inferior Olivary

Electrotonic coupling in the inferior olivary (IO) nucleus is assumed to play a crucial role in generating the subthreshold membrane potential oscillations in olivary neurons and in synchronizing climbing fiber input into the cerebellar cortex. We studied the strength and spatial distribution of the coupling by simultaneous double patch recordings from olivary neurons in the brain slice preparation. Electrotonic coupling was observed in 50% of the cell pairs. The coupling coefficient ( CC), defined as the ratio between voltage responses of the post- and the prejunctional cell, varied between 0.002 and 0.17; most of the pairs were weakly coupled. In more than 75% of the pairs, the CCwas <0.05. The coupling resistance varied between 0.7 to 19.8 GΩ, and 68% of the values fell between 0.7 to 8 GΩ. The difference between the coupling coefficient measured on stimulation of cell 1 or cell 2 of a coupled pair was 27 ± 16%. Direct calculation of the coupling resistance revealed an asymmetry of 24 ± 12%, suggesting a directional preference of coupling. The coupling was voltage independent, although depolarization of either the pre- or the postjunctional neuron reduced the CC. The chance of a cell pair being coupled was 80% in immediate neighboring cells, but dropped to about 30% at a distance of 40 μm. No coupled pairs were observed at distances larger than 70 μm. In 52% of staining experiments neurobiotin injection into an olivary neuron produced indirect labeling of 1–11 nearby cells with an average of 3.8 ± 2.9. All indirectly labeled cells were found in, or immediately adjacent, to the dendritic field of the directly stained neuron. Two distinct morphological types of olivary neurons, “curly” and “straight” cells, were found. In each case all neurons stained indirectly by dye passage through gap junctions belonged to the same type. Using the physiological data we estimated that each olivary neuron is directly coupled to about 50 neurons. Since somatic recordings may not reveal coupling through remote dendrites, we conclude that each neuron is directly connected to ≥50 neurons forming two distinct networks of curly and straight cells.

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