Oxytocin action on components of endoplasmic reticulum in hippocampal neuronal cells

Reduced Neurite Arborization in Primary Dopaminergic Neurons in Autism-Like Shank3B-Deficient Mice

Despite many studies on dopamine changes in autism, specific alterations in midbrain dopamine neurons projecting to the striatum and cortex remain unclear. Mouse models with diverse SH3 domain and ankyrin repeat containing protein 3 (Shank3) deficiencies are used for investigating autistic symptoms and underlying neurobiological mechanisms. SHANK3 belongs to postsynaptic proteins crucial for synapse formation during development, and disruptions in SHANK3 structure could lead to impaired neurite outgrowth and altered dendritic arborization and morphology. Therefore, we aimed to investigate whether Shank3 deficiency (Shank3B) leads to changes in the morphology of primary neuronal cell cultures from dopaminergic brain regions of neonatal mouse pups and whether it results in alterations in synaptic proteins in dopaminergic nerve pathway projection areas (striatum, frontal cortex). Significantly reduced neurite outgrowth was observed in primary dopaminergic neurons from the midbrain and striatum of Shank3-deficient compared to WT mice. A decrease in Synapsin I immunofluorescence signal in the cortical neurons isolated from Shank3-deficient mice was found, although neurite arborization changes were less severe. Importantly, the deficit in the length of the longest neurite was confirmed in primary cortical neurons isolated from Shank3-deficient mice. No changes in the gene expression of synaptic proteins were observed in the striatum and frontal cortex of Shank3-deficient mice, but an altered gene expression profile of dopaminergic receptors was found. These results show structural changes of dopaminergic neurons, which may explain autistic symptomatology in the used model and provide a basis for understanding the long-term development of autistic symptoms.

Oxytocin, GABA, and dopamine interplay in autism

Oxytocin plays an important role in brain development and is associated with various neurotransmitter systems in the brain. Abnormalities in the production, secretion, and distribution of oxytocin in the brain, at least during some stages of the development, are critical for the pathogenesis of neuropsychiatric diseases, particularly in the autism spectrum disorder. The etiology of autism includes changes in local sensory and dopaminergic areas of the brain, which are also supplied by the hypothalamic sources of oxytocin. It is very important to understand their mutual relationship. In this review, the relationship of oxytocin with several components of the dopaminergic system, gamma-aminobutyric acid (GABA) inhibitory neurotransmission and their alterations in the autism spectrum disorder is discussed. Special attention has been paid to the results describing a reduced expression of inhibitory GABAergic markers in the brain in the context of dopaminergic areas in various models of autism. It is presumed that the altered GABAergic neurotransmission, due to the absence or dysfunction of oxytocin at certain developmental stages, disinhibits the dopaminergic signaling and contributes to the autism symptoms.

Oxytocin as neuro-hormone and neuro-regulator exert neuroprotective properties: A mechanistic graphical review

BACKGROUND

Neurodegeneration is progressive cell loss in specific neuronal populations, often resulting in clinical consequences with significant medical, societal, and economic implications. Because of its antioxidant, anti-inflammatory, and anti-apoptotic properties, oxytocin has been proposed as a potential neuroprotective and neurobehavioral therapeutic agent, including modulating mood disturbances and cognitive enchantment.

METHODS

Literature searches were conducted using the following databases Web of Science, PubMed, Elsevier Science Direct, Google Scholar, the Core Collection, and Cochrane from January 2000 to February 2023 for articles dealing with oxytocin neuroprotective properties in preventing or treating neurodegenerative disorders and diseases with a focus on oxidative stress, inflammation, and apoptosis/cell death.

RESULTS

The neuroprotective effects of oxytocin appears to be mediated by its anti-inflammatory properties, inhibition of neuro inflammation, activation of several antioxidant enzymes, inhibition of oxidative stress and free radical formation, activation of free radical scavengers, prevent of mitochondrial dysfunction, and inhibition of apoptosis.

CONCLUSION

Oxytocin acts as a neuroprotective agent by preventing neuro-apoptosis, neuro-inflammation, and neuronal oxidative stress, and by restoring mitochondrial function.