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Introduction: the atrium cardiomyocytes have a group of structures collectively called the secretory apparatus, consisting of the pores of the nuclear membrane, the mitochondria, the endoplasmic reticulum and the Golgi apparatus. These device produces and secretes into the bloodstream, peptides called natriuretic peptides. They are called ANP (atrial natriuretic peptide) and BNP (brain natriuretic peptide), and they work by lowering blood pressure, due to its diuretic action on the kidney. In this work, a literature review was carried out on the ultrastructure and action of the constituent elements of the cardiomyocyte secretory apparatus. ANP and BNP are stored in the cytoplasm of cardiomyocytes in the form of granules of varying sizes. In the presence of arterial hypertension (AH), there is an increase in pressure on the walls of the atria, inducing the secretion of natriuretic peptides (NPs) into the bloodstream, which promote natriuresis, reducing systemic blood pressure. The present work was carried out using the databases of Lilacs, Bireme, Medline via Pubmed and Scielo without distinction of language, in the period between October 2021 and October 2022, using the descriptors "atrial cardiomyocytes, natriuretic peptides and blood pressure". Basic and applied studies performed with healthy human beings and laboratory animals were selected, thus excluding studies with patients and animals presenting any type of comorbidity. [ABSTRACT FROM AUTHOR]

Background/Aims: Cigarette smoking is a key factor in systemic inflammation and oxidative stress, and it has also been associated with the loss of muscle strength and an elevated risk of pulmonary diseases. Thus, this study aimed to analyze the effects of cigarette smoking on the diaphragm muscle structure of postmortem samples. Methods: Immunohistochemical techniques were used for muscle remodeling (metalloproteinases 2 and 9), inflammation (cyclooxygenase-2), oxidative stress (8-hydroxy-2′-deoxyguanosine), and vascularization (vascular endothelial growth factor). Hematoxylin and eosin stain was used for histopathological analysis and Picrosirius stain was used to highlight the collagen fibers. Results: Cigarette smokers had an increase of diaphragm muscle remodeling, oxidative stress, inflammation, and vascularization compared to non-smokers. Conclusion: Diaphragm muscle structure may be negatively affected by cigarette smoking. [ABSTRACT FROM AUTHOR]

Background/Aims: Smoking is a major risk factor for several cardiovascular and pulmonary diseases, and it has also been associated with the loss of skeletal muscle mass and strength leading to sarcopenia. The aim of this is study is to analyze the effects of cigarette smoking on the diaphragm muscle histopathology of postmortem samples from patients without respiratory diseases. Methods: Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. Results: Cigarette smokers had an increase of histopathological alterations as abnormal cytoplasm, abnormal fiber size and shape, and central nucleus. Additionally, smokers had an increase of collagen fibers on diaphragm muscle. Conclusion: Smoking may influence in a negatively fashion the diaphragm musculature. [ABSTRACT FROM AUTHOR]

Introduction It is indicated that aging reduces muscular vascularity. Thus, strategies that aimto reverse or decrease the progression of these changes are suggested. Therefore, the present study aimed to analyze the blood capillary density of the plantaris muscle (PL) of aged rats submitted to strength training and exogenous testosterone use. Methods A total of 30 rats were divided equally into the following groups: EA: 20 months old; OLD: 24 months old; OLD + S: testosterone; ST: strength training; and ST + S: strength training + testosterone. Strength training was performed 3 times a week for 15 weeks. Testosterone administration was performed by the intraperitoneal method 2 times a week at a dose of 10mg/kg. All of the morphological parameters were analyzed using morphoquantitative techniques. Results A significant increase in the capillaries numerical density of the OLD + S and ST + S groups. The OLD + S and ST + S groups demonstrated a higher ratio of capillaries per myofiber than the EA, OLD and ST groups. The OLD and ST groups had a higher ratio than the EA group. The OLD + S, ST and ST + S groups presented a statistically significant increase in the cross-sectional area in the type I fibers when compared with the EA and OLD groups. However, the ST group showed a significant increase compared with the OLD group. In type II fibers, the ST and ST + S groups showed a greater cross-sectional area than the EA group. As for the mean cross-sectional area, the ST and ST + S groups presented significantly larger areas than the other groups. Conclusion Anabolic steroid administration is crucial to increase the blood capillary density of the plantarismuscle of old rats, independently of the effects of strength training. [ABSTRACT FROM AUTHOR]

To explore the effects of physical exercise on the liver of animals in menopause, we analyzed the histomorphometric parameters of the hepatic tissue in ovariectomized and dyslipidemic female mice. The animals were distributed in six groups (n = 5): sedentary control (SC), sedentary ovariectomized control (SOC), trained ovariectomized control (TOC), sedentary LDL knockout (LDL-S), sedentary ovariectomized LDL knockout (LDL-SO), and trained ovariectomized LDL knockout (LDL-TO). At the end of the experiment, the liver and the visceral adipose tissue (VAT) of animals were removed for morphometric and stereological studies. In the LDL-S and LDL-SO animals, both sedentary, results showed reduction in the area (µm2) and major and minor diameters (µm) of hepatocytes and reduction in the portions of large hepatocytes, and increase in the percentage of Kupffer cells. The trained group showed a tendency of increase in the area and diameter and in the percentage of hepatocytes, as well significant reduction in the percentage of Kupffer cells and interstitial tissue. We suggested that training can prevent cell and tissue damage caused by the process of increase in hepatic fat, lipoperoxidation, and tissue inflammation in animals with privation of estrogen and dyslipidemia, apparently reflecting a better metabolic response of the hepatic tissue in organisms undergoing training. [ABSTRACT FROM AUTHOR]

The normal hematological values in various phases of the rat life provide a valuable guide to researchers and could be useful for experimental works. However, database information available on the literature are incomplete.Aim: This study aimed to present normal hematological parameters of young and aged rats.Methods: Male and female rats were distributed into seven experimental groups with 1, 2, 3, 6, 12, 18, and 24 months of age. Blood samples taken from the tails were analyzed. Normal hematological values were determined for each age group.Results: Rats showed a progressive weight gain with advancing age, predominantly after 3 months of life. With advancing age, differences were found on hematological parameters: some of them showed a progressive rise with age and others did not. Hemoglobin levels and hematocrit did not change while the number of circulating red blood cells suffered slight increase.Conclusion: The present study determined the normal values for absolute and relative hematological parameters in Wistar rats from 2 to 24 months for male and female rats. The results can be used in studies of effects of aging, feeding, and medications on growing and aging rats. [ABSTRACT FROM AUTHOR]

Testosterone levels decline gradually with advancing age. At this point, testosterone administration as a therapy has been largely used to improve different outcomes. However, testosterone induces dose-dependent negative effects on the structure and function of the liver across age. Therefore, the present study aimed to carry out a systematic review of the effects of testosterone administration on the hepatic structure of adult and aged animals. We have searched the PubMed, Google Scholar, Science Direct, Scielo and Lilacs databases for animal experimental studies on the effects of testosterone administration on the hepatic structure across age. After applying the inclusion and exclusion criteria, we included two articles in a systematic review and meta-analysis (regarding adult/aged rats). We have shown through a systematic review with meta-analysis that testosterone may cause chronic hepatic congestion. However, the present review had a small number of studies, which was considered a limitation. At this point, we encourage the development of more studies to elucidate the cellular and molecular mechanisms involved in hepatic injuries, as well as the hepatic metabolism of exogenous testosterone across age. [ABSTRACT FROM AUTHOR]

Aging can promote significant morphofunctional changes in the gastrointestinal tract (GIT). Regulation of GIT motility is mainly controlled by the myenteric neurons of the enteric nervous system. Actions that aim at decreasing the aging effects in the GIT include those related to diet, with caloric restriction (CR). The CR is achieved by controlling the amount of food or by manipulating the components of the diet. Therefore, the objective of this study was to evaluate different levels of CR on the plasticity of nicotinamide adenine dinucleotide phosphate– (NADPH-) reactive myenteric neurons in the colon of Wistar rats during the aging process using ultrastructural (transmission electron microscopy) and morphoquantitative analysis. Wistar male rats (Rattus norvegicus) were distributed into 4 groups (n= 10/group): C, 6-month-old animals; SR, 18-month-old animals fed a normal diet; CRI, 18-month-old animals fed a 12% CR diet; CRII, 18-month-old animals fed a 31% CR diet. At 6 months of age, animals were transferred to the laboratory animal facility, where they remained until 18 months of age. Animals of the CRI and CRII groups were submitted to CR for 6 months. In the ultrastructural analysis, a disorganization of the periganglionar matrix with the aging was observed, and this characteristic was not observed in the animals that received hypocaloric diet. It was observed that the restriction of 12.5% and 31% of calories in the diet minimized the increase in density and cell profile of the reactive NADPH neurons, increased with age. This type of diet may be adapted against gastrointestinal disturbances that commonly affect aging individuals. [ABSTRACT FROM PUBLISHER]

The aging process may cause negative physiological changes. However, exercises as resistance training (RT) have been considered an important intervention to attenuate these changes. Additionally, liver plays an important role in blood glucose homeostasis in exercise.Aim: This study aimed to analyze the effects of RT on the liver components of aged animals.Methods: Male Wistar rats were divided into two groups: 24 months' group (CONTROL); and group submitted to a progressive RT protocol for 16 weeks (EXERCISE). Both groups were sacrificed at 24 months.Results: We observed a decrease in blood flow due to the practice of resistance exercises. Besides, our results showed that hepatic tissue plays an important role in glycemic homeostasis during RT. In addition, RT increased mitogen capacity of hepatocytes.Conclusions: Our study showed many implications for the knowledge about the effects of strength training on old animals' liver. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Brasileira de Medicina do Esporte is the property of Redprint Editora Ltda. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)