RESUMEN
Nicotine is the psychoactive component given tobacco has several main components and acts as an agonist for nicotinic acetylcholine receptors (nAChRs) in the nervous system. Although the ligand-gated cation channels known as nAChRs are found throughout the nervous system and body, this review focuses on neuronal nAChRs. Individuals with psychiatric diseases such as schizophrenia, comorbid substance use disorders, attention-deficit hyperactivity disorder, major depression, and bipolar disorder have increased rates of smoking. These psychiatric disorders are associated with various cognitive deficits, including working memory, deficits in attention, and response inhibition functions. The cognitive-enhancing effects of nicotine may be particularly relevant predictors of smoking initiation and continuation in this comorbid population. Individuals with schizophrenia make up a significant proportion of smokers. Literature suggests that patients smoke to alleviate cognitive deficiencies due to the stimulating effects of nicotine. This narrative review examines the role of nicotine on cognition in schizophrenia.
RESUMEN
OBJECTIVE: To determine the level of serotonin in patients of vasovagal syncope and postural tachycardia syndrome after head-up tilt test. METHODS: The cross-sectional analytical study was conducted at the Islamic International Medical College and the Department of Electrophysiology, Armed Forces Institute of Cardiology, Rawalpindi, from April 2017 to March 2018. Group A comprised cases of vasovagal syncope, group B had patients of postural tachycardia syndrome, and group C had healthy controls. Cases were chosen on the basis of history, episodes of syncope and findings of head-up tilt test. After the test, blood samples were taken for hormonal analysis of serotonin using enzyme-linked immunosorbent assay. Data was analysed using SPSS 21. RESULTS: Of the 80 subjects, 35(43.8%) were in group A, 35(43.8%) in group B and 10(12.4%) in group C. Mean serotonin value in group A was 918.39±380.16nM, in group B it was 1188.70±449.55nM., while in control group C the mean value was 771.40±376.14nM (p<0.05). CONCLUSIONS: Serotonin was found to have a significant role in syncope pathophysiology.