The circadian rhythm is a critical system that governs an organism’s functions in alignment with the light-dark cycle. Melatonin release from the pineal gland plays a crucial role in regulating the internal clock of the body. Multiple neurotransmitter systems in the central nervous system are linked to the release of melatonin. In this review, the relationship between circadian rhythm, melatonin secretion and various neurotransmitter systems are mainly discussed. Serotonin regulates the circadian rhythm through projections from raphe nuclei. Agomelatine is an example of the synergistic interaction between melatonin and serotonin. Melatonergic agents and selective serotonin reuptake inhibitors also exert notable impacts on depression in concomitant use. Dopamine has an inhibitory effect on melatonin release, while melatonin also inhibits dopamine release. This should be taken into account when considering the use of melatonin in Parkinson’s disease. On the contrary, use of melatonin may offer therapeutic advantages for schizophrenia and tardive dyskinesia. The interaction between norepinephrine and melatonin exhibits diurnal variability, with norepinephrine promoting arousal and inhibiting daytime melatonin secretion. Melatonergic neurons also exert a specific protective influence on cholinergic neurons. Interaction between the histaminergic and melatonergic systems is significant, particularly in association with immunity, sleep, and circadian rhythm. Novel ligands with dual-acting properties, interacting with both the histaminergic and melatonergic systems are investigated. Currently, there is a limited number of approved melatonergic agents that primarily demonstrate positive effects in addressing insomnia and depression. However, there is considerable potential in studying new agents that target both the melatonergic and other neurotransmitter systems, which alleviate various conditions, including neurodegenerative diseases, dementia, autoimmune diseases, allergic diseases, epilepsy, and other neuropsychiatric disorders. The ongoing process of developing and evaluating new ligands selectively targeting the melatonergic system remains crucial in understanding the complex relationship between these systems.

All living organisms exhibit circadian rhythms. Humans show circadian rhythm of the different physiological functions such as sleep-wake cycle, core body temperature, feeding behavior, metabolic activity, heart rate variability, hormone secretion, and others. The hypothalamic suprachiasmatic nucleus (SCN) acts as a primary circadian pacemaker. Peripheral tissues have an endogenous circadian clock; however, SCN synchronizes the circadian activity of the peripheral clocks. The retinohypothalamic tract (RHT) from retinal ganglionic cells carries the photic signal into the SCN that regulates the rhythmic expression of the core clock genes through the feedback loop. At the output level, the SCN connects with the pineal gland and the peripheral tissues with the help of neuroendocrine mediators. Disruption of circadian clock functions is detrimental to health. Shift work, night work, chronic or acute jet lag, and light-at-night have adverse effects on circadian functions. Misalignment of circadian rhythm alters the expression of core clock genes, leading to deregulation of cellular activity and metabolic functions. Circadian rhythm dysfunction causes many pathologic conditions, including sleep disorders, cardiovascular problems, metabolic dysfunction, infertility, poor physical performance, as well as cancer. The present work has reviewed the relationship between circadian clock dysfunction and impaired physiological activities.

Stroke is a leading cause of morbidity and mortality. The advent of mechanical thrombectomy has largely improved patient outcomes. This article reviews the features and outcomes associated with aspiration, stent retrievers, and combination catheters used in current practice. There is also a discussion on clinical considerations based on anatomical features and clot composition. The reperfusion grading scale and outcome metrics commonly used following thrombectomy when a patient is still in the hospital are reviewed. Lastly, there are proposed discharge and outpatient follow-up goals in caring for patients hospitalized for a stroke.

Astrocytomas include a wide range of tumors with unique mutations and varying grades of malignancy. These tumors all originate from the astrocyte, a star-shaped glial cell that plays a major role in supporting functions of the central nervous system (CNS), including blood-brain barrier (BBB) development and maintenance, water and ion regulation, influencing neuronal synaptogenesis, and stimulating the immunological response. In terms of epidemiology, glioblastoma (GB), the most common and malignant astrocytoma, generally occur with higher rates in Australia, Western Europe, and Canada, with the lowest rates in Southeast Asia. Additionally, significantly higher rates of GB are observed in males and non-Hispanic whites. It has been suggested that higher levels of testosterone observed in biological males may account for the increased rates of GB. Hereditary syndromes such as Cowden, Lynch, Turcot, Li-Fraumeni, and neurofibromatosis type 1 have been linked to increased rates of astrocytoma development. While there are a number of specific gene mutations that may influence malignancy or be targeted in astrocytoma treatment, O⁶-methylguanine-DNA methyltransferase (MGMT) gene function is an important predictor of astrocytoma response to chemotherapeutic agent temozolomide (TMZ). TMZ for primary and bevacizumab in the setting of recurrent tumor formation are two of the main chemotherapeutic agents currently approved in the treatment of astrocytomas. While stereotactic radiosurgery (SRS) has debatable implications for increased survival in comparison to whole-brain radiotherapy (WBRT), SRS demonstrates increased precision with reduced radiation toxicity. When considering surgical resection of astrocytoma, the extent of resection (EoR) is taken into consideration. Subtotal resection (STR) spares the margins of the T1 enhanced magnetic resonance imaging (MRI) region, gross total resection (GTR) includes the margins, and supramaximal resection (SMR) extends beyond the margin of the T1 and into the T2 region. Surgical resection, radiation, and chemotherapy are integral components of astrocytoma treatment.

Epilepsy, a prevalent neurological disorder, is characterized by chronic seizures resulting from abnormal electrical activity in the brain. Adequate medical treatment allows roughly 70% of patients to enjoy a seizure-free life. However, throughout history, epilepsy has acquired diverse interpretations due to the experienced seizures, transforming the condition from a clinical issue into a social stigma. Therefore, the aim of this review study is to review stigma and psychosocial problems in patients with epilepsy (PwE). For this reason, this study utilises sources from the last ten years and reports current data. As a result of the review, it was found that societal discrimination in PwE arises primarily from inadequate knowledge, misconceptions, and negative attitudes toward the condition. Other contributing factors were include patients’ lower levels of education and income, frequent seizures due to inadequate treatment, age at onset, duration of the disease, depressive symptoms, and lack of social support. Also, it was found that the stigma individuals with epilepsy face plays a pivotal role in exacerbating their psychosocial problems. Unfortunately, stigma and psychosocial challenges appear to be in a vicious circle, with an increase in one increasing the other. Stigmatized patients tended to isolate themselves from society, further increasing their likelihood of experiencing a depressive mood or psychiatric comorbidity. Consequently, individuals with epilepsy encounter difficulties in various domains such as marriage, work, education, and personal life. Considering these significant psychosocial burdens, it is essential to recognize that epilepsy surpasses its medical implications. Unfortunately, current efforts to reduce stigma remain insufficient, necessitating urgent and comprehensive measures to address this issue.

Globally, the incidence of Parkinson’s disease (PD) is increasing faster than other neurodegenerative disorders. Neuropathologically, PD is characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta due to the accumulation of aggregates of misfolded α-synuclein (α-Syn) in the cytoplasm of these neurons, forming Lewy bodies. Extracellular vesicles (EVs) are associated with the spread of α-Syn to different brain areas. However, at the same time that these EVs contribute to the pathophysiology of PD, they can also be explored as therapeutic, serving as a vehicle to deliver specific molecules, since these vesicles can easily cross the blood-brain barrier. Thus, this review summarizes the recent progress in EVs as a therapeutic strategy for PD, focusing on their delivery to the brain, and discusses the potential challenges and future directions in this field.