Browse
Submit Data
Databases
API
Help

Dataset Information

10 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Somatostatin-expressing parafacial neurons are CO₂/H⁺ sensitive and regulate baseline breathing.

ABSTRACT: Glutamatergic neurons in the retrotrapezoid nucleus (RTN) function as respiratory chemoreceptors by regulating breathing in response to tissue CO₂/H⁺. The RTN and greater parafacial region may also function as a chemosensing network composed of CO₂/H⁺-sensitive excitatory and inhibitory synaptic interactions. In the context of disease, we showed that loss of inhibitory neural activity in a mouse model of Dravet syndrome disinhibited RTN chemoreceptors and destabilized breathing (Kuo et al., 2019). Despite this, contributions of parafacial inhibitory neurons to control of breathing are unknown, and synaptic properties of RTN neurons have not been characterized. Here, we show the parafacial region contains a limited diversity of inhibitory neurons including somatostatin (Sst)-, parvalbumin (Pvalb)-, and cholecystokinin (Cck)-expressing neurons. Of these, Sst-expressing interneurons appear uniquely inhibited by CO₂/H⁺. We also show RTN chemoreceptors receive inhibitory input that is withdrawn in a CO₂/H⁺-dependent manner, and chemogenetic suppression of Sst+ parafacial neurons, but not Pvalb+ or Cck+ neurons, increases baseline breathing. These results suggest Sst-expressing parafacial neurons contribute to RTN chemoreception and respiratory activity.

SUBMITTER: Cleary CM

PROVIDER: S-EPMC8169115 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Ventral parafacial inhibitory neurons regulate baseline breathing by a mechanism involving disinhibition

Project description:A parafacial region of the medulla called the retrotrapezoid nucleus (RTN) is an important respiratory control center. A group of glutamatergic neurons in this region function as respiratory chemoreceptors by regulating breathing in response to changes in tissue CO2/H+. Cellular mechanisms underlying this function involve H+-inhibition of TASK2 channels and -activation of GPR4 receptors. Evidence also suggests the RTN and greater parafacial region functions as a CO2/H+ sensing network where CO2/H+-activated and -inhibited neurons talk to each other through excitatory and inhibitory interactions. However, contributions of parafacial inhibitory neurons to control of breathing are unknown, and synaptic properties of RTN chemorecpetors have not been characterized. Here, we show the ventral parafacial region contains parvalbumin (Pvalb), cholecystokinin (CCK), neuron-derived neurotrophic factor (Ndnf) and somatostatin (SST) subtypes of interneurons including a subset strongly inhibited by CO2/H+. We also show that chemosensitive RTN neurons receive tonic inhibitory input under control conditions that is withdrawn in a CO2/H+-dependent manner, and chemogenetic inhibition of ventral parafacial inhibitory neurons increases baseline respiratory activity. These results suggest ventral parafacial inhibitory neurons are important determinants of respiratory activity under baseline conditions when the respiratory system is most prone to failure.

2021-05-12 | GSE153172 | GEO

Disordered breathing in a Pitt-Hopkins syndrome model involves Phox2b-expressing parafacial neurons and aberrant Nav1.8 expression.

Project description:Pitt-Hopkins syndrome (PTHS) is a rare autism spectrum-like disorder characterized by intellectual disability, developmental delays, and breathing problems involving episodes of hyperventilation followed by apnea. PTHS is caused by functional haploinsufficiency of the gene encoding transcription factor 4 (Tcf4). Despite the severity of this disease, mechanisms contributing to PTHS behavioral abnormalities are not well understood. Here, we show that a Tcf4 truncation (Tcf4tr/+) mouse model of PTHS exhibits breathing problems similar to PTHS patients. This behavioral deficit is associated with selective loss of putative expiratory parafacial neurons and compromised function of neurons in the retrotrapezoid nucleus that regulate breathing in response to tissue CO2/H+. We also show that central Nav1.8 channels can be targeted pharmacologically to improve respiratory function at the cellular and behavioral levels in Tcf4tr/+ mice, thus establishing Nav1.8 as a high priority target with therapeutic potential in PTHS.

| S-EPMC8514575 | biostudies-literature

Ventral parafacial inhibitory neurons regulate baseline breathing by a mechanism involving disinhibition

Project description:Ventral parafacial inhibitory neurons regulate baseline breathing by a mechanism involving disinhibition

| PRJNA641666 | ENA

Disordered breathing in Pitt Hopkins syndrome involves disruption of parafacial respiratory neurons and aberrant expression of Nav1.8.

Project description:Pitt-Hopkins syndrome (PTHS) is a rare autism spectrum-like disorder characterized by intellectual disability, developmental delays and breathing problems involving episodes of hyperventilation followed by apnea. PTHS is caused by functional haploinsufficiency of the gene encoding transcription factor 4 (Tcf4). Despite the severity of this disease, virtually nothing is known regarding mechanisms contributing to PTHS behavioral abnormalities, and candidate therapeutic targets are lacking. Here, we show that a Tcf4 truncation (Tcf4tr/+) mouse model of PTHS recapitulates respiratory phenotypes observed in PTHS patients. The basis of this behavior deficit involves selective loss of putative expiratory parafacial neurons and compromised function of neurons in the retrotrapezoid nucleus that regulate breathing in response to tissue CO2/H+. We also show that central Nav1.8 channels can be targeted pharmacologically to improve respiratory function at the cellular and behavioral levels in Tcf4tr/+ mice, thus establishing Nav1.8 as a high priority target with therapeutic potential in PTHS.

2021-09-02 | GSE174417 | GEO

Silencing preBotzinger complex somatostatin-expressing neurons induces persistent apnea in awake rat.

Project description:Delineating neurons that underlie complex behaviors is of fundamental interest. Using adeno-associated virus 2, we expressed the Drosophila allatostatin receptor in somatostatin (Sst)-expressing neurons in the preBötzinger Complex (preBötC). Rapid silencing of these neurons in awake rats induced a persistent apnea without any respiratory movements to rescue their breathing. We hypothesize that breathing requires preBötC Sst neurons and that their sudden depression can lead to serious, even fatal, respiratory failure.

| S-EPMC2515565 | biostudies-literature

Somatostatin-Expressing Interneurons Enable and Maintain Learning-Dependent Sequential Activation of Pyramidal Neurons.

Project description:The activities of neuronal populations exhibit temporal sequences that are thought to mediate spatial navigation, cognitive processing, and motor actions. The mechanisms underlying the generation and maintenance of sequential neuronal activity remain unclear. We found that layer 2 and/or 3 pyramidal neurons (PNs) showed sequential activation in the mouse primary motor cortex during motor skill learning. Concomitantly, the activity of somatostatin (SST)-expressing interneurons increased and decreased in a task-specific manner. Activating SST interneurons during motor training, either directly or via inhibiting vasoactive-intestinal-peptide-expressing interneurons, prevented learning-induced sequential activities of PNs and behavioral improvement. Conversely, inactivating SST interneurons during the learning of a new motor task reversed sequential activities and behavioral improvement that occurred during a previous task. Furthermore, the control of SST interneurons over sequential activation of PNs required CaMKII-dependent synaptic plasticity. These findings indicate that SST interneurons enable and maintain synaptic plasticity-dependent sequential activation of PNs during motor skill learning.

| S-EPMC6555419 | biostudies-literature

Induction of human somatostatin and parvalbumin neurons by expressing a single transcription factor LIM homeobox 6.

Project description:Human GABAergic interneurons (GIN) are implicated in normal brain function and in numerous mental disorders. However, the generation of functional human GIN subtypes from human pluripotent stem cells (hPSCs) has not been established. By expressing LHX6, a transcriptional factor that is critical for GIN development, we induced hPSCs to form GINs, including somatostatin (SST, 29%) and parvalbumin (PV, 21%) neurons. Our RNAseq results also confirmed the alteration of GIN identity with the overexpression of LHX6. Five months after transplantation into the mouse brain, the human GABA precursors generated increased population of SST and PV neurons by overexpressing LHX6. Importantly, the grafted human GINs exhibited functional electrophysiological properties and even fast-spiking-like action potentials. Thus, expression of the single transcription factor LHX6 under our GIN differentiation condition is sufficient to robustly induce human PV and SST subtypes.

| S-EPMC6181563 | biostudies-literature

Estrogen receptor-? expressing neurons in the ventrolateral VMH regulate glucose balance.

Project description:Brain glucose-sensing neurons detect glucose fluctuations and prevent severe hypoglycemia, but mechanisms mediating functions of these glucose-sensing neurons are unclear. Here we report that estrogen receptor-? (ER?)-expressing neurons in the ventrolateral subdivision of the ventromedial hypothalamic nucleus (vlVMH) can sense glucose fluctuations, being glucose-inhibited neurons (GI-ER?vlVMH) or glucose-excited neurons (GE-ER?vlVMH). Hypoglycemia activates GI-ER?vlVMH neurons via the anoctamin 4 channel, and inhibits GE-ER?vlVMH neurons through opening the ATP-sensitive potassium channel. Further, we show that GI-ER?vlVMH neurons preferentially project to the medioposterior arcuate nucleus of the hypothalamus (mpARH) and GE-ER?vlVMH neurons preferentially project to the dorsal Raphe nuclei (DRN). Activation of ER?vlVMH to mpARH circuit and inhibition of ER?vlVMH to DRN circuit both increase blood glucose. Thus, our results indicate that ER?vlVMH neurons detect glucose fluctuations and prevent severe hypoglycemia in mice.

| S-EPMC7195451 | biostudies-literature

Characterization of Neurons Expressing the Novel Analgesic Drug Target Somatostatin Receptor 4 in Mouse and Human Brains.

Project description:Somatostatin is an important mood and pain-regulating neuropeptide, which exerts analgesic, anti-inflammatory, and antidepressant effects via its Gi protein-coupled receptor subtype 4 (SST4) without endocrine actions. SST4 is suggested to be a unique novel drug target for chronic neuropathic pain, and depression, as a common comorbidity. However, its neuronal expression and cellular mechanism are poorly understood. Therefore, our goals were (i) to elucidate the expression pattern of Sstr4/SSTR4 mRNA, (ii) to characterize neurochemically, and (iii) electrophysiologically the Sstr4/SSTR4-expressing neuronal populations in the mouse and human brains. Here, we describe SST4 expression pattern in the nuclei of the mouse nociceptive and anti-nociceptive pathways as well as in human brain regions, and provide neurochemical and electrophysiological characterization of the SST4-expressing neurons. Intense or moderate SST4 expression was demonstrated predominantly in glutamatergic neurons in the major components of the pain matrix mostly also involved in mood regulation. The SST4 agonist J-2156 significantly decreased the firing rate of layer V pyramidal neurons by augmenting the depolarization-activated, non-inactivating K+ current (M-current) leading to remarkable inhibition. These are the first translational results explaining the mechanisms of action of SST4 agonists as novel analgesic and antidepressant candidates.

| S-EPMC7589422 | biostudies-literature

Discrete TrkB-expressing neurons of the dorsomedial hypothalamus regulate feeding and thermogenesis.

Project description:Mutations in the TrkB neurotrophin receptor lead to profound obesity in humans, and expression of TrkB in the dorsomedial hypothalamus (DMH) is critical for maintaining energy homeostasis. However, the functional implications of TrkB-fexpressing neurons in the DMH (DMHTrkB) on energy expenditure are unclear. Additionally, the neurocircuitry underlying the effect of DMHTrkB neurons on energy homeostasis has not been explored. In this study, we show that activation of DMHTrkB neurons leads to a robust increase in adaptive thermogenesis and energy expenditure without altering heart rate or blood pressure, while silencing DMHTrkB neurons impairs thermogenesis. Furthermore, we reveal neuroanatomically and functionally distinct populations of DMHTrkB neurons that regulate food intake or thermogenesis. Activation of DMHTrkB neurons projecting to the raphe pallidus (RPa) stimulates thermogenesis and increased energy expenditure, whereas DMHTrkB neurons that send collaterals to the paraventricular hypothalamus (PVH) and preoptic area (POA) inhibit feeding. Together, our findings provide evidence that DMHTrkB neuronal activity plays an important role in regulating energy expenditure and delineate distinct neurocircuits that underly the separate effects of DMHTrkB neuronal activity on food intake and thermogenesis.

| S-EPMC7848633 | biostudies-literature