Stress induces various neurobiological responses and causes psychiatric disorders, including depression. Monoamine oxidase A (MAO-A) plays an important role in various functions of the brain, such as regulation of mood, anxiety and aggression, and dysregulation of MAO-A is observed in stress-related psychiatric disorders. This study addressed the question whether acute social stress induces changes to transcriptional and/or post-transcriptional regulation of MAO-A expression in the brain. Using male Nile tilapia (Oreochromis niloticus), we investigated whether acute social stress, induced by the presence of a dominant male fish, changes the expression of MAO-A. We measured gene expression of MAO-A by quantitative PCR, enzymatic activity of MAO-A by the luminescent method, and 5-HT and 5-HIAA levels by liquid chromatography-mass spectrometry in the brain of socially stressed and control fish. Socially stressed males showed decreased MAO-A mRNA levels, consistent MAO-A enzymatic activity, increased 5-HT turnover in the brain, and elevated plasma cortisol levels, compared to controls. Our results suggest that acute social stress suppresses the transcription of MAO-A gene, enhances 5-HT metabolism but does not affect the production of MAO-A protein.
Cannabis sativa (CS, familyCannabinaceae) has been reported for its anti-emetic activity against cancer chemotherapy-induced emesis in animal models and in clinics. The current study was designed to investigateCSfor potential effectiveness to attenuate cisplatin-induced vomiting in healthy pigeons and to study the impact on neurotransmitters involved centrally and peripherally in the act of vomiting. High-performance liquid chromatography system coupled with electrochemical detector was used for the quantification of neurotransmitters 5-hydroxytryptamine (5HT), dopamine (DA) and their metabolites; Di-hydroxy Phenyl Acetic acid (Dopac), Homovanillic acid (HVA), and 5-hydroxy indole acetic acid (5HIAA) centrally in specific brain areas (area postrema and brain stem) while, peripherally in small intestine. Cisplatin (7 mg/kg i.v.) induce emesis without lethality across the 24 h observation period.CShexane fraction (CS-HexFr; 10 mg/kg) attenuated cisplatin-induced emesis ∼ 65.85% (P< 0.05); the reference anti-emetic drug, metoclopramide (MCP; 30 mg/kg), produced ∼43.90% reduction (P< 0.05). At acute time point (3rdh), CS-HexFr decreased (P< 0.001) the concentration of 5HT and 5HIAA in the area postrema, brain stem and intestine, while at 18thh (delayed time point) CS-HexFr attenuated (P< 0.001) the upsurge of 5HT caused by cisplatin in the brain stem and intestine and dopamine in the area postrema.CS-HexFr treatment alone did not alter the basal neurotransmitters and their metabolites in the brain areas and intestine except 5HIAA and HVA, which were decreased significantly. In conclusion the anti-emetic effect ofCS-HexFr is mediated by anti-serotonergic and anti-dopaminergic components in a blended manner at the two different time points, i.e., 3rdand 18thh in pigeons.
Gastroenteropancreatic neuroendocrine tumours (GEP- nETs) are rare neoplasms with a complex spectrum of presentation. The study cohort (n=64) included the diagnoses of carcinoid, (n=26, 41%), insulinoma, (n=25, 39%), undetermined (n=10, 16%), VIPoma, glucagonoma and multiple endocrine neoplasia (MEn-1) (n= 3). Almost half of the patients (n=31) had distant metastasis at diagnosis, the commonest being carcinoid tumours. Presenting symptoms were due to either hormonal expressions or mass effects. diagnoses in all patients were made based on positive immunohistochemical staining for chromogranin and synaptophysin. Less than half (n=30) had either serum chromogranin A, urinary 5-hydroxyindole acetic acid (5-hIAA), serum insulin or C-peptide levels performed. Commonest diagnostic imaging modalities were computed tomography (CT) scan (94%) and abdominal ultrasound (15%). Curative or palliative surgery was performed in 58 patients. Systemic therapy included long acting somatostatin analogues (n=14), chemotherapy (n=7) and interferon-α2b (n=1). nine patients died, all of who had metastatic disease at diagnosis. All patients with insulinoma (n=25) were assessed by endocrinologists whilst carcinoid tumours were mainly managed by surgeons (n=16/26). Involvements of oncologists and gastroenterologists were minimal. This study showed that patients with GEP-nETs in Malaysia commonly presented late in the disease with presence of distant metastases. Less than half had adequate hormonal and biochemical examinations performed for diagnostic as well as prognostic purposes, and only a third received systemic therapy. Lack of institutionalbased database, clinical expertise and multi-disciplinary involvement contributed to the inadequate surveillance and management of the disease.