Biomedical subjects

N Tritos

Publications and source records attributed to N Tritos.

5 recordsLinked to original sources

PubMed1999

Neurotransmitter modulation of glucocorticoid receptor mRNA levels in the rat hippocampus.

Glucocorticoids in the hippocampus mediate adaptive responses elicited by stressful stimuli. In this study we investigated glucocorticoid receptor gene expression in the rat hippocampus following acute stress. A significant decrease in glucocorticoid receptor mRNA levels was observed in the hippocampus less than 1 h after the onset of stress. This decrease was inhibited by administering either MK-801, diazepam or propranolol prior to exposure to stress. The effect of diazepam on the stress-induced decrease in hippocampal glucocorticoid receptor mRNA was reversed by Ro-15-1788, suggesting that it is mediated by central benzodiazepine receptors, i.e. GABA-A. These results indicate that NMDA, GABA-A and beta-adrenergic receptors are involved in the mechanism of the stress-induced decrease in glucocorticoid receptor mRNA levels in the rat hippocampus.

Adrenergic beta-Antagonists↗

PubMed1998

Beta-adrenergic receptors mediate a stress-induced decrease in IGF-II mRNA in the rat cerebellum.

1. Exposure to a combined forced swimming-confinement stress resulted in a decrease in insulin-like growth factor II (IGF-II) mRNA levels in the whole brain (without the cerebellum) and in the isolated brain areas of the cerebral cortex, the hippocampus, and the cerebellum. 2. In an effort to elucidate the neurotransmitter systems involved in this stress-induced decrease, animals were injected prior to exposure to the stress, with either propranolol, diazepam, or MK-801. 3. Administration of diazepam or MK-801 did not affect the stress-induced decrease in IGF-II mRNA in any of the three brain areas examined. 4. Administration of propranolol prior to the exposure to the stress inhibited the stress-induced decrease in IGF-II mRNA in the cerebellum. Propranolol had no such effect in the cerebral cortex or the hippocampus. 5. Our results suggest that in the cerebellum, the stress-induced decrease in IGF-II mRNA is mediated by beta 2-adrenergic receptors.

Adrenal Cortex Hormones↗

PubMed1997

At least three neurotransmitter systems mediate a stress-induced increase in c-fos mRNA in different rat brain areas.

1. Protooncogene c-fos mRNA levels were determined in the rat cerebral cortex, hippocampus, and cerebellum after exposure to a combined forced swimming and confinement stress. The stress resulted in an increase in c-fos mRNA levels in all three brain areas. 2. In an effort to elucidate the neurotransmitter systems involved in this stress-induced increase, animals were injected, prior to exposure to the stress, with either diazepam, MK-801, or propranolol. 3. In both the cerebral cortex and the hippocampus the stress-induced increase in c-fos mRNA was inhibited by MK-801, suggesting that it is mediated via NMDA receptors. In the hippocampus, propranolol had a similar effect, indicating that beta-adrenergic receptors are also involved in the stress-induced increase in c-fos mRNA. 4. On the other hand, the increase in c-fos mRNA produced by the stress of the injection was inhibited in the cerebral cortex by diazepam or propranolol and in the hippocampus only by diazepam. Furthermore, administration of MK-801 resulted in an increase in c-fos mRNA in the hippocampus of the nonstressed animals. In the cerebellum no one of the three drugs employed affected c-fos mRNA levels in either stressed or nonstressed animals. 5. Our results thus show that various forms of stress activate, in different brain areas, neurons with either NMDA, beta-adrenergic, and/or GABA-A receptors.

Animals↗

PubMed1993

Pattern of treatment among diabetic patients in a sample of urban Greek population.

It is well known that therapeutic habits and diabetic patient's compliance differ substantially between different populations. It is also accepted that if patients are recruited in specialized diabetes centers some important bias is likely to occur, e.g. an excess of insulin-treated subjects. Therefore, population studies are very helpful in order to establish treatment patterns in different populations. A descriptive study was performed during an epidemiological survey conducted on 12,842 randomly selected inhabitants of a suburb of Athens (both sexes, all ages). 509 persons were recorded as known diabetics. Information concerning the type of treatment was collected. Reliable data were available on 490 diabetic individuals. 145 (29.6%) of them were following diet alone, while 270 (55.1%) were receiving antidiabetic tablets and only 75 (15.1%) injected insulin. In patients 40 years old or more (n = 471), the corresponding numbers were 30.1, 56.5 and 13.4% respectively. Thus, it is obvious that insulin-treated patients represent a small percentage of the total diabetic population. It seems that these differences are caused by genetic as well as other factors.

Adolescent↗

PubMedDate not supplied

Evidence for an increase in the prevalence of known diabetes in a sample of an urban population in Greece.

It is accepted that the prevalence of known diabetes mellitus has increased in some countries, although the available data are incomplete and sometimes anecdotal. In 1974 a sample of the urban population (n = 21,410) in a suburb of Athens (Greece) was evaluated for the prevalence of known diabetes mellitus. The study was repeated 17 years later in the same area under the same conditions and methodology on 12,836 randomly selected inhabitants (both sexes, all ages). Visiting nurses contacted the inhabitants at home and filled in a questionnaire. The results show a clear increase in diabetes prevalence of the population as a whole (standardized rates: 1974: 2.4% (95% confidence intervals 2.2-2.6%) 1990: 3.1 (2.8-3.4%)). Standardization was done on the basis of data obtained from the same census. The changes were statistically significant in the 50-59, 60-69, and 70-79 age groups (1974: 5.87, 10.98, and 11.41%; 1990: 7.70, 13.68, and 19.52%, respectively). Thus, the prevalence of known diabetes mellitus has considerably increased during the last 17 years in a sample of urban Greek population.

Age Factors↗