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Neurodegeneration
Published in Ibrahim Natalwala, Ammar Natalwala, E Glucksman, MCQs in Neurology and Neurosurgery for Medical Students, 2022
Ibrahim Natalwala, Ammar Natalwala, E Glucksman
FALSE – Dopamine is degraded by monoamine oxidase B. Inhibitors of this isoform, such as selegiline, are helpful in Parkinson’s disease as they increase the availability of dopamine. Monoamine oxidase A preferentially metabolises serotonin and noradrenaline.4
Dermal and Transdermal Drug Delivery Systems
Published in Tapash K. Ghosh, Dermal Drug Delivery, 2020
Kenneth A. Walters, Majella E. Lane
Bodkin and Amsterdam (2002) randomly assigned 177 adult outpatients with major depressive disorder to receive transdermal selegiline (20 mg patch applied once daily) or placebo for six weeks. Diet was restricted to reduce the level of intake of tyramine. Greater improvement was observed after six weeks in patients treated with transdermal selegiline than in those given placebo. There were no differences in adverse events for the patients given selegiline and those given placebo, although application site reactions were more common with the selegiline transdermal system. Importantly, the side effects commonly seen with traditional monoamine oxidase inhibitor antidepressants were not observed. This was followed by a double-blind study that included younger patients with no dietary restrictions (Amsterdam, 2003). In this study, 289 patients (18 to 65 years old) were randomly assigned to receive either a 20 mg patch daily or placebo for up to eight weeks. The results demonstrated that transdermal selegiline had a statistically significant but modest antidepressant effect compared with placebo in the absence of a tyramine-restricted diet. Once again side effects were similar for treatment and placebo groups, with the exception of application site reaction, which was observed in 31.5% of treatment patients and 15.1% of placebo-treated patients.
Social Psychology
Published in Mohamed Ahmed Abd El-Hay, Understanding Psychology for Medicine and Nursing, 2019
The monoamine oxidase A (MAOA) gene controls the amount of the monoamine oxidase (MAO) enzyme that regulates the activity of a number of neurotransmitters, including serotonin and norepinephrine. People who have low MAOA gene expression tend to behave aggressively when provoked (McDermott, Tingley, Cowden, Frazzetto, & Johnson, 2009). Nielson et al. (1994) found preliminary evidence that a disturbance in coding for tryptophan hydroxylase, the rate-limiting enzyme in serotonin synthesis, correlates with impulsive aggressive behavior. However, there is no evidence that there is a specific genetic locus, and it is unknown whether a family history of violence signifies genetic transmission or learned behavior. Violence is likely a polygenetic phenomenon, with many genes acting in a coordinated fashion to produce an aggressive phenotype (Cadoret, Leve, & Devor, 1997).
Curcumin improves the ability of donepezil to ameliorate memory impairment in Drosophila melanogaster: involvement of cholinergic and cnc/Nrf2-redox systems
Published in Drug and Chemical Toxicology, 2023
Opeyemi Babatunde Ogunsuyi, Olayemi Philemon Aro, Ganiyu Oboh, Olawande Chinedu Olagoke
Monoamine oxidase (MAO), which catalyze the breakdown of amines, is often linked to mental and neurological conditions including depression, AD, and Parkinson’s disease (Sturza et al. 2013, Adedayo et al. 2022). Depletion of monoamine neurotransmitters and increased generation of free radicals are brought on by an increase in MAO activity (as shown in Al-induced flies) (Bayir et al. 2006, Adedayo et al. 2022). There are reports that MAO inhibition offers therapeutic benefits, as this ensures antidepressant and antianxiety outcomes (Lühr et al. 2010). In agreement with earlier studies, DON and CUR significantly ameliorated the increased MAO activities in Al-exposed flies. This study was therefore able to show the anti-MAO activities of CUR + DON. However, combining CUR with low dose DON (12.5 µg/g) resulted in no significant difference in the ameliorative effect of DON alone (25 µg/g), suggesting that the therapeutic properties of DON could be conserved at half concentration in the presence of CUR.
Hypericin, a medicinal compound from St. John’s Wort, inhibits genotoxicity induced by mutagenic agents in V79 cells
Published in Drug and Chemical Toxicology, 2022
Larissa Mendes de Souza, Fernanda Diniz de Sousa, Roberta Cristina Ribeiro Cruz, Denise Crispim Tavares, Pollyanna Francielli de Oliveira
Herraiz and Guillén (2018) report that the MAO-A inhibition by H. perforatum extract indicates the occurrence of inhibitors in which the hypericin, hyperforin, and flavonoids are possible contributors to this inhibition. The hypericin inhibits MAO-A with an IC50 of 35.5 ± 2.1 µM or 17.9 µg/mL. MAO-A is an enzyme monoamine oxidase that metabolizes xenobiotic, endogenous amines, and neurotransmitters including serotonin, dopamine, norepinephrine, tyramine, tryptamine, and the neurotoxin MPTP (Herraiz et al.2013, Herraiz et al.2018). During this process, MAO-A generates hydrogen peroxide (H2O2) that is involved in oxidative cell damage and pathological conditions (Herraiz and Guillén 2018). Thus, the inhibition of MAO-A may result in specific antioxidant actions (Herraiz et al.2013).
Investigation of anti-Parkinson activity of dicyclomine
Published in International Journal of Neuroscience, 2022
Maham Sanawar, Uzma Saleem, Fareeha Anwar, Samra Nazir, Muhammad Furqan Akhtar, Bashir Ahmad, Tariq Ismail
Parkinson’s disease (PD) is the second most common neurodegenerative disorder after Alzheimer which affects substantia nigra and globus pallidus in brain region followed by the destruction of dopaminergic neurons [1]. It is caused by age, genetic effects and due to the stressful lifestyle environment [2]. The onset of disease is about 1% at the age of 65 which increased to 5% at the age of 85 years [3]. Motor symptoms include bradykinesia, rigidity and tremor [4]. Non-motor symptoms are depression and sleep disorders are common [5]. There is also a significant reduction in antioxidant enzymes was observed in the PD patients which results in loss of cholinergic, nor-adrenergic and dopaminergic neurons [6]. The natural defense mechanism is provided by three primary enzymes which include superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) which plays an important role in combating the oxidative stress [7]. From the last decades, monoamine oxidase (MAO) inhibitors were extensively used in the depressive illnesses, but later on, its use was decreased due to side effects [8]. MAO is involved in the process of deamination of primary, secondary and tertiary amines. This deamination resulted the aldehyde and free amine production with the generation of free hydrogen peroxide.