Synaptic activity-induced Ca(2+) signaling in avian cochlear nucleus magnocellularis neurons.
Animals; Calcium Signaling/*physiology; Chick Embryo; Chickens; Cochlear Nucleus/*metabolism; GABA-A/metabolism; Inhibitory Postsynaptic Potentials/physiology; Neurons/*metabolism; Organ Culture Techniques; Patch-Clamp Techniques; Receptors; Synapses/*metabolism; Synaptic Transmission/*physiology
Neurons of the avian cochlear nucleus magnocellularis (NM) receive glutamatergic inputs from the spiral ganglion cells via the auditory nerve and feedback GABAergic inputs primarily from the superior olivary nucleus. We investigated regulation of Ca(2+) signaling in NM neurons with ratiometric Ca(2+) imaging in chicken brain slices. Application of exogenous glutamate or GABA increased the intracellular Ca(2+) concentration ([Ca(2+)](i)) in NM neurons. Interestingly,
Wang Lie-Cheng; Tang Zheng-Quan; Lu Yong
Neuroscience research
2012
2012-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neures.2011.11.004" target="_blank" rel="noreferrer noopener">10.1016/j.neures.2011.11.004</a>
Glycinergic inhibition creates a form of auditory spectral integration in nuclei of the lateral lemniscus.
Acoustic Stimulation; Action Potentials/drug effects; Animals; Auditory Perception/drug effects/*physiology; Bicuculline/pharmacology; Brain Stem/drug effects/*physiology; Chiroptera; GABA Antagonists/pharmacology; GABA-A Receptor Antagonists; GABA-A/metabolism; gamma-Aminobutyric Acid/metabolism; Glycine Agents/pharmacology; Glycine/*physiology; Glycine/antagonists & inhibitors/metabolism; Microelectrodes; Neural Inhibition/drug effects/*physiology; Neurons/drug effects/*physiology; Receptors; Strychnine/pharmacology
For analyses of complex sounds, many neurons integrate information across different spectral elements via suppressive effects that are distant from the neurons' excitatory tuning. In the mustached bat, suppression evoked by sounds within the first sonar harmonic (23-30 kHz) or in the subsonar band (\textless23 kHz) alters responsiveness to the higher best frequencies of many neurons. This study examined features and mechanisms associated with low-frequency (LF) suppression among neurons of the lateral lemniscal nuclei (NLL). We obtained extracellular recordings from neurons in the intermediate and ventral nuclei of the lateral lemniscus, observing different forms of LF suppression related to the two above-cited frequency bands. To understand the mechanisms underlying this suppression in NLL neurons, we examined the roles of glycinergic and GABAergic input through local microiontophoretic application of strychnine, an antagonist to glycine receptors (GlyRs), or bicuculline, an antagonist to gamma-aminobutyric acid type A receptors (GABA(A)Rs). With blockade of GABA(A)Rs, neurons showed an increase in firing rate to best frequency (BF) and/or LF tones but retained LF suppression of BF sounds. For neurons that displayed LF suppression tuned to
Peterson Diana Coomes; Nataraj Kiran; Wenstrup Jeffrey
Journal of neurophysiology
2009
2009-08
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.00040.2009" target="_blank" rel="noreferrer noopener">10.1152/jn.00040.2009</a>
Development of GPCR modulation of GABAergic transmission in chicken nucleus laminaris neurons.
Animals; Patch-Clamp Techniques; *Synaptic Transmission; gamma-Aminobutyric Acid/*metabolism; Neurons/*metabolism; Brain/*cytology; Chickens/*metabolism; Synapses/metabolism; Receptors; G-Protein-Coupled/*metabolism; GABA-A/metabolism; GABA-B/metabolism; Metabotropic Glutamate/metabolism
Neurons in the nucleus laminaris (NL) of birds act as coincidence detectors and encode interaural time difference to localize the sound source in the azimuth plane. GABAergic transmission in a number of CNS nuclei including the NL is subject to a dual modulation by presynaptic GABA(B) receptors (GABA(B)Rs) and metabotropic glutamate receptors (mGluRs). Here, using in vitro whole-cell patch clamp recordings from acute brain slices of the chick, we characterized the following important but unknown properties pertaining to such a dual modulation: (1) emergence of functional GABA synapses in NL neurons; (2) the temporal onset of neuromodulation mediated by GABA(B)Rs and mGluRs; and (3) the physiological conditions under which GABA(B)Rs and mGluRs are activated by endogenous transmitters. We found that (1) GABA(A)R-mediated synaptic responses were observed in about half of the neurons at embryonic day 11 (E11); (2) GABA(B)R-mediated modulation of the GABAergic transmission was detectable at E11, whereas the modulation by mGluRs did not emerge until E15; and (3) endogenous activity of GABA(B)Rs was induced by both low- (5 or 10 Hz) and high-frequency (200 Hz) stimulation of the GABAergic pathway, whereas endogenous activity of mGluRs was induced by high- (200 Hz) but not low-frequency (5 or 10 Hz) stimulation of the glutamatergic pathway. Furthermore, the endogenous activity of mGluRs was mediated by group II but not group III members. Therefore, autoreceptor-mediated modulation of GABAergic transmission emerges at the same time when the GABA synapses become functional. Heteroreceptor-mediated modulation appears at a later time and is receptor type dependent in vitro.
Tang Zheng-Quan; Lu Yong
PloS one
2012
1905-07
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1371/journal.pone.0035831" target="_blank" rel="noreferrer noopener">10.1371/journal.pone.0035831</a>
Synaptic Inhibition in Avian Interaural Level Difference Sound Localizing Neurons.
Female; Male; Animals; Acoustic Stimulation/methods; Tissue Culture Techniques; Chick Embryo; Patch-Clamp Techniques; *dorsal nucleus of the lateral lemniscus; *GABAA receptor; *interaural level difference; *reversal potential; *synaptic inhibition; Anions/metabolism; Avian Proteins/metabolism; Brain Stem/cytology/drug effects/*physiology; Chlorides/metabolism; Electric Stimulation; gamma-Aminobutyric Acid/metabolism; Intracellular Space/drug effects/metabolism; Neural Inhibition/drug effects/*physiology; Neurons/cytology/drug effects/*physiology; Sound Localization/drug effects/*physiology; Symporters/metabolism; Synaptic Transmission/drug effects/*physiology; Receptors; GABA-A/metabolism; Glycine/metabolism
Synaptic inhibition plays a fundamental role in the neural computation of the interaural level difference (ILD), an important cue for the localization of high-frequency sound. Here, we studied the inhibitory synaptic currents in the chicken posterior portion of the dorsal nucleus of the lateral lemniscus (LLDp), the first binaural level difference encoder of the avian auditory pathway. Using whole-cell recordings in brain slices, we provide the first evidence confirming a monosynaptic inhibition driven by direct electrical and chemical stimulation of the contralateral LLDp, establishing the reciprocal inhibitory connection between the two LLDps, a long-standing assumption in the field. This inhibition was largely mediated by GABAA receptors; however, functional glycine receptors were also identified. The reversal potential for the Cl(-) channels measured with gramicidin-perforated patch recordings was hyperpolarizing (-88 mV), corresponding to a low intracellular Cl(-) concentration (5.2 mm). Pharmacological manipulations of KCC2 (outwardly Cl(-) transporter) activity demonstrate that LLDp neurons can maintain a low intracellular Cl(-) concentration under a high Cl(-) load, allowing for the maintenance of hyperpolarizing inhibition. We further demonstrate that hyperpolarizing inhibition was more effective at regulating cellular excitability than depolarizing inhibition in LLDp neurons.
Curry Rebecca J; Lu Yong
eNeuro
2016
2016-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1523/ENEURO.0309-16.2016" target="_blank" rel="noreferrer noopener">10.1523/ENEURO.0309-16.2016</a>