The postnatal development of ultrasonic vocalization-associated breathing is altered in glycine transporter 2-deficient mice.

Key Points: Newborn mice produce ultrasonic vocalization to communicate with their mother. The neuronal glycine transporter (GlyT2) is required for efficient loading of synaptic vesicles in glycinergic neurons. Mice lacking GlyT2 develop a phenotype that resembles human hyperekplexia and the mice die in the second postnatal week.

A neuronal role of the Alanine-Serine-Cysteine-1 transporter (SLC7A10, Asc-1) for glycine inhibitory transmission and respiratory pattern.

The Alanine-Serine-Cysteine-1 transporter (SLC7A10, Asc-1) has been shown to play a role in synaptic availability of glycine although the exact mechanism remains unclear. We used electrophysiological recordings and biochemical experiments to investigate the role of Asc-1 transporter in glycinergic transmission in the brainstem respiratory network. Using both the Asc-1 substrate and transportable inhibitor D-isoleucine (D-Ile), and the non-transportable Asc-1 blocker Lu AE00527 (Lu), we found that D-Ile reduces glycinergic transmission and increases glycine release via hetero-exchange, whereas Lu has no acute effect on glycinergic synaptic transmission.

Breathing disturbances in a model of Rett syndrome: A potential involvement of the glycine receptor α3 subunit?

The glycine receptor α3 subunit is known to be a target for cAMP/PKA-mediated phosphorylation and regulation. Mice that lack this subunit are apparently normal but the 5-HT-receptor mediated modulation of respiratory network activity is disturbed. Since the intracellular cAMP-concentration is reduced in mice that lack the transcriptional modulator methyl-CpG-binding protein 2 (MeCP2) gene, we aimed to test if the α3 subunit of the glycine receptor is involved in the development of the breathing phenotype of MeCP2-deficient mice (Mecp2).

GlyT2-Dependent Preservation of MECP2-Expression in Inhibitory Neurons Improves Early Respiratory Symptoms but Does Not Rescue Survival in a Mouse Model of Rett Syndrome.

Mutations in methyl-CpG-binding protein 2 (MECP2) gene have been shown to manifest in a neurodevelopmental disorder that is called Rett syndrome. A typical problem that occurs during development is a disturbance of breathing. To address the role of inhibitory neurons, we generated a mouse line that restores MECP2 in inhibitory neurons in the brainstem by crossbreeding a mouse line that expresses the Cre-recombinase (Cre) in inhibitory neurons under the control of the glycine transporter 2 (GlyT2, slc6a5) promotor (GlyT2-Cre) with a mouse line that has a floxed-stop mutation of the Mecp2 gene (Mecp2 (stop/y)).

microRNA targeting of the P2X7 purinoceptor opposes a contralateral epileptogenic focus in the hippocampus.

The ATP-gated ionotropic P2X7 receptor (P2X7R) modulates glial activation, cytokine production and neurotransmitter release following brain injury. Levels of the P2X7R are increased in experimental and human epilepsy but the mechanisms controlling P2X7R expression remain poorly understood. Here we investigated P2X7R responses after focal-onset status epilepticus in mice, comparing changes in the damaged, ipsilateral hippocampus to the spared, contralateral hippocampus.

P2X7 receptor inhibition interrupts the progression of seizures in immature rats and reduces hippocampal damage.

Aims: Early-life seizures, particularly when prolonged, may be harmful to the brain. Current pharmacotherapy is often ineffective; therefore, novel neuro- and/or glio-transmitter systems should be explored for targeting. The P2X7 receptor is a cation-permeable channel with trophic and excitability effects on neurons and glia which is activated by high amounts of ATP that may be released in the setting of injury after severe seizures.

Increased neocortical expression of the P2X7 receptor after status epilepticus and anticonvulsant effect of P2X7 receptor antagonist A-438079.

Purpose: ATP is an essential transmitter/cotransmitter in neuron function and pathophysiology and has recently emerged as a potential contributor to prolonged seizures (status epilepticus) through the activation of the purinergic ionotropic P2X7 receptor (P2X7R). Increased P2X7R expression has been reported in the hippocampus, and P2X7R antagonists reduced seizure-induced damage to this brain region. However, status epilepticus also produces damage to the neocortex.

CHOP regulates the p53-MDM2 axis and is required for neuronal survival after seizures.

Hippocampal sclerosis is a frequent pathological finding in patients with temporal lobe epilepsy and can be caused by prolonged single or repeated brief seizures. Both DNA damage and endoplasmic reticulum stress have been implicated as underlying molecular mechanisms in seizure-induced brain injury. The CCAAT/enhancer-binding protein homologous protein (CHOP) is a transcriptional regulator induced downstream of DNA damage and endoplasmic reticulum stress, which can promote or inhibit apoptosis according to context.

Seizure suppression and neuroprotection by targeting the purinergic P2X7 receptor during status epilepticus in mice.

Prolonged seizures [status epilepticus (SE)] constitute a neurological emergency that can permanently damage the brain. SE results from a failure of the normal mechanisms to terminate seizures; in particular, γ-amino butyric acid-mediated inhibition, and benzodiazepine anticonvulsants are often incompletely effective. ATP acts as a fast neurotransmitter via ionotropic ligand-gated P2X receptors.