Page 12 - BH-2-2

Brain & Heart Oxidative stress and neurological disorders

Mitochondrial-derived vesicles are also associated with the 7. Oxidative stress in neuropsychiatric
activation of hyper-fragmented mitochondria and giant disorders
mitochondria nucleoids, which can trigger the immune
response. Altered mitochondrial metabolism, increased 7.1. Schizophrenia
55
membrane permeability, decreased membrane potential, and Schizophrenia is a severe mental disorder that affects
excess production of ROS and energy deficits are associated approximately 0.4% of the global population, imposing
with neurological disorders and their progression. 56 significant emotional and financial burdens on both
patients and their families. Characterized by a diverse range
6. Neurological disorder of symptoms, schizophrenia manifests as a heterogeneous

Neurological disorders are defined medically as disorder, encompassing both positive and negative
conditions that affect biochemical, structural, or symptoms. Positive symptoms include thought disorders,
electrical abnormalities in the brain, spinal cord, or other hallucinations, and delusions, whereas negative symptoms
nerves, often resulting in a range of symptoms such as include social withdrawal and poverty of thought. Notably,
paralysis, muscle weakness, poor coordination, loss of 50–90% of schizophrenia patients exhibit negative
66
sensation, seizures, and altered levels of consciousness. symptoms during their first episode of illness.
57
Broadly, neurological disorders are classified into three Patients diagnosed with schizophrenia experience
categories: (i) neuropsychiatric disorders, such as auditory verbal hallucinations (AVHs), which are prevalent
schizophrenia, bipolar disorder, anxiety, and seizures; (ii) in around 70% of cases. AVHs involve patients hearing
neurodegenerative disorders, such as Parkinson’s disease, voices that are unreal, without any external sound stimuli.
Huntington’s disease, and Alzheimer’s disease; and (iii) In general, these voices consist of insulting comments or
neurocognitive disorders, such as dementia, autism, and negative remarks directed toward the patients, potentially
delirium. Neuropsychiatric disorders represent a spectrum prompting self-harm, suicidal tendencies, or extreme
of syndromes where an individual’s cognitive, behavioral, violence. 67
and emotional abilities are affected. Common examples Psychiatrists managing schizophrenia often emphasize
58
include schizophrenia, major depressive disorder (MDD), the adage, “Time is cognition.” Emerging but limited
attention deficit hyperactivity disorder (ADHD), and evidence suggests that early intervention before the onset
bipolar disorder. Despite their high prevalence, these of psychosis is crucial for preserving patients’ functional
disorders can have profoundly debilitating effects. In ability and cognition. Therapy, social support, and
addition, anxiety stands out as a major neuropsychiatric psychoeducation are all very important and significant
problem, particularly prevalent during adolescence aspects of the treatment of different stages of schizophrenia.
(Table 1). Antipsychotics serve as the primary pharmacological

Table 1. Changes in the activity of synaptic protein in neurological disorders
Synaptic Functions of protein Change in Location in brain References
proteins Name of proteins activity of protein
α-synuclein Presynaptic chaperone Decreased Cultured neurons and brain homogenates 59
VAMP2 VAMP2 in the synaptic vesicles Decreased Primary motor, somatosensory, and parietal 60
areas of the cerebral cortex, synaptosomes
PSD-95 Postsynaptic density protein Increased Cortical layers I, II/III, and V 61
Synaptophysin Synaptic vesicle membrane protein Decreased Rostral cortex 62
involved in endocytosis
Complexin-1 Exocytosis of synaptic vesicles Decreased Hippocampus 63
Syntaxin-1A SNARE complex Decreased Hippocampus 64
MAP1A Microtubule cross-linking protein Decreased Hippocampus 65
Homer-1 Protein in the post-synaptic density of Decreased Primary motor, somatosensory, and parietal 66
excitatory synapses areas of the cerebral cortex
SNAP25 t-SNARE Decreased Synaptosomes 67
MAP1B Microtubule cross-linking protein Decreased Hippocampus 68
Abbreviations: MAP1A: Microtubule-associated protein 1A; MAP1B: Microtubule-associated protein 1B; PSD-95: Postsynaptic density protein
95; SNAP25: Synaptosomal-associated protein, 25kDa; VAMP2: Vesicles-associated membrane protein-2.

Volume 2 Issue 2 (2024) 6 doi: 10.36922/bh.2704