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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]

Changes in the heart compartments that leads to pathological cardiac hypertrophy can be related to testosterone reduction in aging males since heart cells are susceptible to androgens. Resistance exercise delays the changes of aging. Aim: This study aimed to analyze alterations of the left ventricle of aged rats subjected to resistance exercise with administration of testosterone. Methods: Wistar rats were divided into five groups: C Group (control), S Group (sedentary), ST Group (sedentary treated with testosterone), T Group (trained) and TT Group (trained and treated with testosterone), strength training protocol and testosterone treatment were 16 weeks long. All groups were sacrificed at 16 months except for C group, sacrificed at 13 months. Results: There was no change in the weight of the heart or the left ventricle between the groups. ST group showed increase in Nv [cap] density of capillaries and collagen, with no differences in interstitial space. Both trained groups (T and TT) showed increase in the numerical density of capillaries (Nv [cap]) and in the interstitial space, with no changes in collagen. Conclusion: Resistance exercise combined with testosterone triggered a response of compensatory adjustment in the increase of Nv [cap], collagen and interstitial space, increasing perfusion and nutrition to the heart. [ABSTRACT FROM AUTHOR]

Background: Studying the effects of smoking intensity is important to evaluate the risk of tobacco use on a range of illnesses, such as as sarcopenia among the elderly. Thus, this study aimed to analyze the effects of pack-years of cigarette smoking on the diaphragm muscle (DIAm) histopathology of postmortem samples. Methods: Subjects were divided into three groups: never-smoker (n = 46); less than 30 pack-years of smoking (n = 12); and more than 30 pack-years of smoking (n = 30). Diaphragm samples were stained with Picrosirius red and hematoxylin and eosin stain for general structure. Results: Participants with more than 30 pack-years of cigarette smoking had a significant increase in adipocytes, blood vessels and collagen deposit, as well as an increase in histopathological alterations. Conclusions: Pack-years of smoking was associated with DIAm injury. However, further clinicopathological studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

Sarcopenia is characterized as aging-related weakness and atrophy, which decreases the diaphragm force generating capacity leading to a decrease of expulsive non-ventilatory motor behaviors, which are critical for airway clearance. Thus, this study aimed to analyze the histopathology of the diaphragm in postmortem samples. Thirty individuals were included. Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. We observed a positive association between advancing age and histopathological findings in the diaphragm structure. We suggest that age is a key factor in increasing diaphragm muscle histopathology. However, further clinicopathological studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

The atrial natriuretic peptide (ANP) is a peptide hormone that is mainly produced in the cardiocytes of the atria and auricles, where it is stored within secretory granules. The aim of the present work was to analyze the effects of pre- and postnatal protein malnutrition on weight gain, the size of the heart and the number and sizes of the ANP-granules in the cardiocytes of the rat’s right auricle. This study was conducted on 21-day-old rats from mothers exposed to 73% protein restriction during the gestation and lactation and on age-matched control animals. At this stage, both control and protein-deprived animals were killed by a lethal intraperitonial injection of sodic pentobarbital. The weight and the size of the heart were determined and ANP-granules of auricular cardiocytes were examined by transmission electron microscopy and ultrastructural morphometry. Protein deprivation of the mother throughout pregnancy, and the mother and unweaned rat pups in the first 21 postnatal days reduced the weights of pups to about 60% of the normally fed group. The weight and size of the heart were also reduced, by about 50%. Despite this, perinatal malnutrition did not significantly affect the numbers of ANP-granules/field in the cardiocytes. However, there was a small but significant reduction in the sizes of granules. It is concluded that ANP-granules are protected from loss even when there is a substantial reduction in body weight and organ size caused by protein deprivation. [ABSTRACT FROM AUTHOR]

Abstract: The location of myosin-V in whole mount preparations of the peritracheal and intrapulmonary peribronchial plexuses of Wistar rats has been shown by using an affinity-purified antibody specific to the medial tail domain of myosin-V. Myosin-V immunostaining was intense in the peritracheal and intrapulmonary peribronchial plexuses, allowing the visualization of neuronal cell bodies and fibers. Knowledge of the cellular localization and function of this class of myosin is an important achievement, as it allows the study of these plexuses so as to clarify the importance of the complex mechanism responsible for the functioning of the airways. [Copyright &y& Elsevier]

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]

This study demonstrates that aging of the atrial cardiomyocyte is associated with a morphometric alteration in their cytoplasmic organelles linked to the natriuretic peptides production. Consequently, a decrease in size and number of the peptide's granules were evidenced. Abbreviations: ER, endoplasmic reticulum; G, Golgi complex; M, mitochondria; N, nucleus; RA, right atrium. • Cardiac atria secretes natriuretic peptides that act in regulation of blood pressure. • Aging of the atrial cardiomyocyte is associated with alteration in their organelles. • Decrease in size and number of peptides vesicles was verified in aging rats. The cardiac atria secrets polypeptide hormones usually called natriuretic peptides (NPs). These substances play a relevant role in the blood pressure regulation. The objective of the study was to estimate the effects of aging on the secretory apparatus of NPs in cardiomyocytes of the right atrium. Twenty male Wistar rats were studied: 10 young animals aged 3 months old (237 ± 27 g; mean ± SD) and 10 old animals aged 20 months old (450 ± 68 g; mean ± SD). The systolic blood pressure was verified instants before the moment of the euthanasia. Electron micrographs were prepared to quantify the area and density of the NP granules and the relative volumes of the endoplasmic reticulum, Golgi complex, and mitochondria. In addition, the number of pores per 10 μm of karyotheca was another variable evaluated. The significance of the results between the two groups evaluated was analyzed by the Studentʼs t test (p < 0.05). The cardiomyocytes obtained from animals of the old group showed decreased in sectional area and density of secretory granules of NP and lower relative volume of endoplasmic reticulum, Golgi complex, and mitochondria compared with the young rats. Moreover, the quantitative density of nuclear pores was significantly lower compared with the youngers. Aging causes hypotrophy of the cardiomyocytes of right atrium, similar to what occurs in ventricular cardiomyocytes. [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]

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 objective of the present study was to analyze alterations of the femoral nerve of aged rats subjected to aerobic training. Wistar rats (12-mo of age) were divided in to two groups: S group (sedentary) and T group (trained). The exercise protocol were 16 weeks long. The groups were sacrificed at 16 months. Ultrafine sections of the femoral nerve have been used. There was no change in the body weight between the groups. T group showed a significant increase in myelinated fiber area, axon diameter, myelin sheath thickness and myelin fiber number compared with sedentary controls. In exercised trained animals, histograms of the frequency distribution of myelinated axons according to their areas showed increased number of medium and large fibers in relation to small fibers, which decreased in number. Aerobic training animals, showed the distribution of myelinated fiber population according to their area being bimodal, with the distribution shifted to the right, indicating increased fiber area. The T group showed a percent damage of large myelinated fibers significantly lower compared to controls. No significant difference was observed between the groups for the g- ratio. The T group also showed a significant increase in the number of microtubules and neurofilaments in myelinated fibers, which was not observed in S group. In conclusion, aerobic training improves nerve structure without evidence of nerve damage and produces an attenuation on the modifications in femoral nerve that develop in old age. [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]

This study aimed to analyze the effects of caloric restriction on aged femoral articular cartilage of Wistar rats. Three groups of eight animals each were considered: young (YC) and old (OC) control groups fed with a normal diet and old caloric restriction group (OCR) composed of 18-month-old animals fed with a 31% less caloric diet from 6-months of age. Articular cartilage was studied through morphometry and immunohistochemistry. Body mass was 12% less in the OCR group than in the OC group. The articular cartilage from OC rats show thinner medial condyles, fewer chondrocytes, smaller chondrocytes nuclear volume and, in both condyles, a predominance of collagen type II and less collagen density compared to both YC and OCR groups (p < .001). In contrast, OCR articular cartilage show thicker medial condyles, larger chondrocytes nuclear volume and increased collagen density compared to OC group (p < 0.001). We concluded that caloric restriction minimizes the effects of aging on medial condyles of the femoral articular cartilage. [ABSTRACT FROM PUBLISHER]

Aging males have a decrease in testosterone levels, by which the testosterone treatment may influence in a negatively fashion the liver.Aim: This study aimed to analyze the effects of aging with or without testosterone administration on the liver components of animals.Methods: Wistar rats were divided into three groups: 20 months' group (G20), 24 months' group (G24), group treated with testosterone for 16 weeks (GT). All groups were sacrificed at 24 months except for G20 that was sacrificed at 20 months.Results: Aging and testosterone treatment alters the body weight (BW), liver weight (LW) and relative liver weight. Besides, testosterone increased the mitogen capacity of hepatocytes. Nonetheless, we reinforce the negative effects of testosterone on old animals' liver as chronic hepatic congestion and/or cholestasis. In addition, we observed that testosterone plays an important role on hepatic glycogen stores.Conclusions: Our study showed many implications for the knowledge about the effects of aging with or without testosterone administration on old animals' liver. [ABSTRACT FROM AUTHOR]

Background: During almost one-third of our life, maturation of the nervous system promotes strength and muscle mass increase. However, as age advances, the nervous system begins to suffer a slow and continue reduction of its functions. Neuromuscular junction (NMJ) is one of the structures of which change due to aging process. Physical training leads to significant adjustments in NMJs of young and aged animals. Nevertheless, studies that aimed to investigate this effect have, in many cases, methodological variables that may have some influence on the result. Thus, this study aimed to carry out a systematic review about the effects of exercise training on the NMJ compartments of young, adult and aged animals. Results: We searched PubMed, Google Scholar, Science Direct, Scielo and Lilacs databases for animal experimental studies that studied exercise effects on the NMJs components across age. After inclusion and exclusion criteria, we included nine articles in systematic review and two for meta-analysis (young/adult NMJ). Conclusions: We identified that exercise training cause NMJ hypertrophy on young animals and NMJ compression on aged ones. However, many methodological issues such as age, skeletal muscle and fibers type, and type of exercise and training protocol might influence the results. [ABSTRACT FROM AUTHOR]

Background: The estrogen deficiency, abnormal lipid profile, weight gain and a sedentary lifestyle are factors associated with the increased prevalence of cardiovascular disease in menopausal women. However, physical exercise practice reduces some of these risk factors. Moreover, it has been shown that exercise has an impact on inflammation, in sympathetic activity and improves endothelial function. Aims: The present study aims to evaluate the effects of moderate aerobic training on biochemical, morphological and physiological parameters in LDL Knockout mice with estrogen deprivation, evaluating the components of the ascending aortic wall. Methods: The animals were randomly divided into six groups (n=5): sedentary control (SC), sedentary control ovariectomized (SCO), trained control ovariectomized (TCO), LDL-Knockout sedentary (KS), LDL-Knockout sedentary ovariectomized (KOS) and LDL-Knockout trained ovariectomized (KOT). The trained groups underwent a protocol of moderate training for 4 weeks on a treadmill with speed and progressive load. After training, blood samples were collected for biochemical assessments and the aorta was removed for dissection and histological morphometry study. In addition, the expression of angiotensin-converting enzyme (ACE) and angiotensin II proteins were examined by immunohistochemistry in all groups of animals. Results: Changes of expressions of ACE and angiotensin II were found when the group was subjected to exercise. The concentrations of cholesterol and triglycerides were lower in the groups of animals with estrogen deprivation and dyslipidemia. In animals that performed exercises we found significant increase (p<0.05) in Vv[lam]; decrease in Vv[col] and CWT, and a tendency for decrease both in TS and IMT when compared to the SC groups. The histological morphometry findings showed consistency in the results of the aorta study when the ovariectomized group underwent the exercise protocol. Conclusion: We conclude that physical training contributed to reducing vessel rigidity and to improvements in vascular compliance, with the increase in volume density of elastic lamellae in the estrogen-deprived groups who had normal cholesterol levels. © 2015 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Introduction: We evaluated the role of cardiovascular autonomic changes in hemodynamics at rest and in response to exercise in streptozotocin-induced diabetic rats. Methods: Male Wistar rats were divided into nondiabetic (ND, n = 8) and diabetic (D, n = 8) groups. Arterial pressure signals were recorded in the basal state and after atropine or propranolol injections at rest, during exercise and during recovery. Results: At rest, vagal tonus was reduced in D (37 ± 3 bpm) in comparison with the ND group (61 ± 9 bpm). Heart rate during exercise was lower in D in relation to ND rats associated with reduced vagal withdrawal in the D group. The D rats had an increase in vagal tonus in the recovery period (49 ± 6 bpm). Conclusions: Exercise-induced hemodynamic adjustment impairment in diabetic rats was associated with reduced cardiac vagal control. The vagal dysfunction was attenuated after aerobic exercise, reinforcing the positive role of this approach in the management of cardiovascular risk in diabetics. Muscle Nerve 46: 96-101, 2012 [ABSTRACT FROM AUTHOR]

Abstract: The practice of regular exercise is indicated to prevent some motility disturbances in the gastrointestinal tract, such as constipation, during aging. The motility alterations are intimately linked with its innervations. The goal of this study is to determine whether a program of exercise (running on the treadmill), during 6 months, has effects in the myenteric neurons (NADH- and NADPH-diaphorase stained neurons) in the colon of rats during aging. Male Wister rats 6 months (adult) and 12 months (middle-aged) old were divided into 3 different groups: AS (adult sedentary), MS (middle-aged sedentary) and MT (middle-aged submitted to physical activity). The aging did not cause a decline significant (p >0.05) of the number of NADH-diaphorase stained neurons in sedentary rats (AS vs. MS group). In contrast, a decline of 31% was observed to NADPH-diaphorase stained neurons. Thus, animals that underwent physical activity (AS vs. MT group) rescued neurons from degeneration caused by aging (total number, density and profile of neurons did not change with age – NADH-diaphorase method). On the other hand, physical activity augmented the decline of NADPH-diaphorase positive neurons (total number, density and profile of neurons decreased). Collectively, the results show that exercise inhibits age-related decline of myenteric neurons however, exercise augments the decline of neurons with inhibitory activity (nitric oxide) in the colon of the rats. [Copyright &y& Elsevier]

Somatic nuclear transfer allows scientists to produce identical copies of individuals (clones) and offers the potential for research in various fields. However, the production of cloned bovines is inefficient, partly because of high rates of embryonic mortality associated with abnormal placental development, although the exact mechanisms are still unclear. In the present study, we have applied design-based stereological methods to quantify placental morphology in cloned and non-cloned Nelore bovines (280–297 days of gestation). We have found no differences for any of the following parameters: number and volume of placentomes, villous volume and surface area, volume and number of star volume units and placental efficiency. Therefore, placental deficiency is unlikely to be attributable to its villous component. Nevertheless, new studies should focus on other placental constituents, e.g. capillaries, trophoblast cells and feto-maternal exchange surface area. [ABSTRACT FROM AUTHOR]

Background: The present study was conducted to determine the location, the morphology and distribution of NADPH-diaphorase positive neurons in the cardiac nerve plexus of the atria of mice (ASn). This plexus lies over the muscular layer of the atria, dorsal to the muscle itself, in the connective tissue of the subepicardium. NADPH- diaphorase staining was performed on wholemount preparations of the atria mice. For descriptive purposes, all data are presented as means ± SEM. Results: The majority of the NADPH-diaphorase positive neurons were observed in the ganglia of the plexus. A few single neurons were also observed. The number of NADPH-d positive neurons was 57 ± 4 (ranging from 39 to 79 neurons). The ganglion neurons were located in 3 distinct groups: (1) in the region situated cranial to the pulmonary veins, (2) caudally to the pulmonary veins, and (3) in the atrial groove. The largest group of neurons was located cranially to the pulmonary veins (66.7%). Three morphological types of NADPH-diaphorase neurons could be distinguished on the basis of their shape: unipolar cells, bipolar cells and cells with three processes (multipolar cells). The unipolar neurons predominated (78.9%), whereas the multipolar were encountered less frequently (5,3%). The sizes (area of maximal cell profile) of the neurons ranged from about 90 μm2to about 220 μm2. Morphometrically, the three types of neurons were similar and there were no significant differences in their sizes. The total number of cardiac neurons (obtained by staining the neurons with NADH-diaphorase method) was 530 ± 23. Therefore, the NADPH-diaphorase positive neurons of the heart represent 10% of the number of cardiac neurons stained by NADH. Conclusion: The obtained data have shown that the NADPH-d positive neurons in the cardiac plexus of the atria of mice are morphologically different, and therefore, it is possible that the function of the neurons may also be different. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the effects of diabetes on quantitative parameters of right atrial cardiomyocytes of elderly rats. Wistar rats (14 months of age) were divided into two groups: streptozotocin-diabetic rats (DG) and control rats (CG). The groups were sacrificed at 16 months. Ultrafine sections of the right atrium were analyzed by electron microscopy. In elderly diabetic animals, histograms of the frequency distribution of natriuretic peptides according to their size showed increased number of small and medium peptides in relation to large peptides, which increased its numerical density leading to a decrease in the mean diameter of both natriuretic peptides. However, elderly diabetic animals remained normotensive. No significant difference was observed between the groups for the volume density of mitochondria, endoplasmic reticulum, and Golgi apparatus. In conclusion, elderly diabetic rats showed increased functional activity of atrial cardiomyocytes with greater production of natriuretic peptides in association with a quantitative maintenance of cytoplasmic components. • The numerical density of ANP and BNP in cardiomyocytes was significantly higher in the diabetic elderly animals. • The ANP and BNP granule size was significantly lower in the diabetic group. • At the end of the experiment, diabetic animals remained normotensive. • The density of cytoplasmic organelles of the cardiomyocytes was not influenced by diabetes. [ABSTRACT FROM AUTHOR]