The Mammalian Locus Coeruleus Complex—Consistencies and Variances in Nuclear Organization

Descriptions of the nuclear parcellation of the locus coeruleus complex have been provided in approximately 80 mammal species spanning the phylogenetic breadth of this class. Within the mammalian rostral hindbrain, noradrenergic neurons (revealed with tyrosine hydroxylase and dopamine-ß-hydroxylase immunohistochemistry) have been observed within the periventricular grey matter (A4 and A6 nuclei) and parvicellular reticular nucleus (A5 and A7 nuclei), with the one exception to date being the tree pangolin, where no A4/A6 neurons are observed. The alphanumeric nomenclature system, developed in laboratory rodent brains, has been adapted to cover the variation observed across species. Cross-species homology is observed regarding the nuclear organization of noradrenergic neurons located in the parvicellular reticular nucleus (A5 and A7). In contrast, significant variations are observed in the organization of the A6 neurons of the locus coeruleus proper. In most mammals, the A6 is comprised of a moderate density of neurons, but in Murid rodents, primates, and megachiropteran bats, the A6 exhibits a very high density of neurons. In primates and megachiropterans, there is an additional moderate density of A6 neurons located rostromedial to the high-density portion. These variations are of importance in understanding the translation of findings in laboratory rodents to humans.

Microstructure of the nerve plexus of the muscular membrane of the gut of domestic ducks (Anas platyrhynchos domesticus) of different ages

As evidenced by the publications of recent years, contrary to the existing dogma about the immutability of the state of the enteric nervous system during the postnatal period of ontogenesis, the population of intestinal neurons is a dynamic formation, decreasing with age and changing due to the action of environmental factors. The current article presents the results of study of the microscopic structure of the nerve plexus of the muscular membrane of the enteric nervous system of domestic ducks (Anas platyrhynchos domesticus) of the black white–breasted breed, of nine age groups of 1–365 days of age. The topography, number, area of nerve nodes, as well as the density of neurons in them were determined on transverse sections of the duodenum, jejunum, ileum, caecum and rectum. For the purpose of a generalized assessment of the morphofunctional state of the nerve plexuses, two parameters were determined: the average age indicator of the gut and intestines. The average age indicator of a certain structure of each intestine was determined as the arithmetical average of its nine age indicators. The average age indicator of a certain gut structure was determined as the arithmetic average of the average age indicator of the structure of all five intestines. It has been established that the nerve plexus of the muscular membrane (myenteric, plexus Auerbachi) of the gut of domestic ducks, in contrast to mammals, is not located between the layers of the muscular membrane, but in its outer layer. On a transverse section of the gut wall, the myenteric ganglia and cords that connect have a predominantly elliptical shape. Despite a significant increase with age in the diameter and thickness of the gut wall, the total number of myenteric ganglia changed little, increasing or decreasing with varying degrees of reliability relative to the previous age. In the gut of ducks, during the first year of the postnatal period of ontogenesis, the smallest number of myenteric ganglia was found in the cecum, and the largest – in the ileum. The general pattern of the dynamics of the size of the myenteric ganglia of the gut of ducks was an increase in their area with age. Moreover, this indicator reached the greatest value at different ages of ducks: at 30 days of age in the ileum and cecum, at 180 days of age – in the rectum and at 365 days of age – in the duodenum. The smallest area of the myenteric ganglia was found in the jejunum, and the largest – in the duodenum and ileum. The smallest number of neurons in the ganglion was found in the cecum, and the largest – in the rectum, the lowest density of neurons in the ganglion was found in the cecum, and the largest – in the jejunum. The general quantitative pattern of neurons in the ganglion was the decrease in their density with age. Changes in the morphometric parameters of the ganglia of the nerve plexus of the muscular membrane of the ducks’ gut indicate the plasticity of the enteric nervous system, its ability to dynamically respond to the action of factors of the internal and external environment. It is promising to study the state of the submucous nerve plexus, as well as the cellular composition of the population of neurons of the enteric nervous system of domestic and wild poultry.

Microstructure of submucosal nervous plexuses of intestines of ducks

There are presented the results of the experimental research of the histological structure of the submucosal nerve plexuses in the intestines of domestic ducks (Anas platyrhynchos domesticus) of 9 age groups from diurnal to 1-year-old of the black White-Breasted breed. The definitions of topography, number, ganglia area, as well as density of neurons in them were determined on cross sections of the duodenum, jejunum, ileum, cecum and rectum. It is defined the nerve nodes and submucosal strands belonging to the enteric nervous system are located between the lamina muscularis mucosae and the inner layer of muscular tunic. In the cross section of the intestinal wall, the submucosal ganglia have the shape of narrow strips. In order to generalize the morphofunctional state of the nerve plexuses, there were determined two parameters: the average age indicator (AAI) of the intestine and intestine. AAI of a certain structure of each intestine was determined as the arithmetic mean of the values of its 9 age indicators. The AAI of a particular intestinal structure was determined as the arithmetic mean of the AAI quantities of the structure of all five intestines. The average number of submucosal ganglia did not increase with the age of the ducks, but changed with varying degrees of reliability in comparison with the previous age. In the intestines of diurnal to 1-day – 1-year-old ducks, the smallest number of submucosal ganglia was found in the cecum, and the largest was found in the rectum. The general pattern of the size dynamics of the submucosal ganglia in the intestines of ducks is an increase with age in their average area. There was found the smallest area of submucosal ganglia in the ileum in the group of ducks of different ages, and the largest was found in the duodenum and cecum. The lowest density of neurons in the submucosal ganglia is found in the cecum, the highest was found in the rectum. Changes in the morphometric parameters of the nerve plexuses ganglia in the intestines of ducks indicate the dynamic nature of changes in the morphofunctional state of the enteric nervous system.

Морфологические особенности развития головного мозга крыс из пометов различной численности в молочном и препубертатном периодах онтогенеза

The authors studied the brain of 14- and 40-days old rats out of naturally scanty and large litters (SL and LL). An average number of rats in LL was 10,8 in a litter, in SL – 5,5; in 40-day old – 12 and 3,7 respectively In both age groups rats out of SL had larger (р<0,05), than in LL absolute mass of the brain, hemispheres and smaller relative mass of the brain, decreased number density of neurons in the cortex of the temporal lobe proper (PLP). The sizes of neurons in layer V of PLP in 14- and 40-day old rats out SL were larger than in LL. (р<0,05). In 40-day old rats out of SL the sizes of neurons in layer II of PLP and hyppocampus were smaller than in rats out of LL. (р<0,05). RNA concentration in cytoplasm did not have significant differences between the groups in the neurons of PLP < in the neurons of hyppocampus in rats out of SL it was higher than in rats out of LL. (р<0,05). NADN-d activity in the neurons of layer II of PLP in the brain of the rats out of SL was lower than than in LL., in layer V and hyppocampus neurons reliable differences between the groups were absent. NADFN-d activity in cytoplasm of neurons in neocortex and hyppocampus in 40-day old rats out of SL was lower of the same parameter in rats out of LL. (р<0,05).

Влияние пренатального и постнатального уменьшения численности пометов на некоторые показатели развития головного мозга крыс в молочном периоде онтогенеза

The authors studied the brain of 14 day old rats born in diminished by number litters (n=7,7±0,7), received from mating females having been exposed to the removal of right uterine horn (1,5 month before mating) and a day after delivery – with litter diminishing up to 5-6. The control group included rats from the litters with an average amount 10,8±1,1, which were off spring from intact males and females. At the age of 14-days experimental animals had a higher body mass, and adrenals mass (P<0,05), and testes (P>0,05) than the control group. Their brain and cerebral hemispheres had increased mass. The thickness of cortex and parietal lobe proper layer I did not show any reliable diff erences between the groups. Number density of neurons in layer II and V in the experimental rats was decreased, the size of cytoplasm of hippo-campus neurons and nucleoli in the neuron layer II PLP were reliably increased compared to the control group. The obtained data confi rm than diminished number of animals in a litter in the prenatal and early postnatal periods odontogenesis is refl ected on the parameters of brain development. At the same time, the diff erences with the control are of the same type and are more pronounced than when the number of animals in a litter is decreased straight after birth.

MLP Modeling and Prediction of IP Subnet Packets Forwarding Performance

In IP networks, packets forwarding performance can be improved by adding more nodes and dividing the network into smaller segments. Being able to measure and predict traffic flows to direct to a given segment can be crucial in respecting traffic shaping, scheduling and QoS. This paper proposes to model network packets forwarding performance for optimization and prediction purposes by using multi-layer feed-forward neural network model that uses sigmoid functions to activate the hidden nodes. Gradient descent technique has been considered to optimize and enhance the MLP accuracy. Simulations of MPL neurons training stages pointed out a relative improvement of the forwarding process when network posses a larger density of neurons. Numerical results validated our theoretical analysis and confirmed that to enhance the forwarding process, it is necessary to divide the network into small segments by optimizing resources allocation.

The Contribution of Brain-Derived Neurotrophic Factor (BDNF) and its TrkB Receptor to Hippocampal Neuron Resistance to Ischemia-Reperfusion (Experimental Study)

The purpose of the study: to assess the content of BDNF and its TrkB receptor in the populations of hippocampal pyramidal neurons in the post-resuscitation period and to identify the contribution of these factors to the neuron resistance to ischemia.Material and methods. The condition of populations of pyramidal neurons of the CA1 and CA4 hippocampus fields was investigated in white mature male rats that underwent a 10-minute cardiac arrest at different periods of the post-resuscitation period (1st, 4th, 7th, 14th day). Animals after a sham surgery served as a reference group. Immunocytochemical methods were used to determine immunoreactivity to BDNF and TrkB proteins. Based on the visual inspection and analysis of the optical density, the following types of neurons with different color intensity were distinguished: weak (BDNF–, TrkB–), moderate (BDNF+, TrkB+) and strong (BDNF++, TrkB++). The total density of neurons and the number of cells with different immunoreactivity to the studied proteins per 1 mm of length were determined. We used the Olympus BX-41 microscope and Image Scope M, ImageJ 1.48 v, MS Excel software. Statistical data processing was performed using Statistica 7.0 software.Results. There was a decrease in the overall density of the population of pyramidal neurons in both studied fields of the hippocampus of the resuscitated animals as compared to the reference group: in the CA1field, on the 4th day after cardiac arrest (26%); in the CA4 field, on the 7th day (38.5%). It was found that the number of BDNF+ neurons doubled in the CA4 field on the 4th day, and the number of BDNF++ neurons decreased. On the 7th day, the number of BDNF– cells decreased sharply, the number of BDNF+ cells decreased to the reference level, and the number of BDNF++ neurons remained reduced vs. the reference group. There was a decrease in the number of BDNF– and BDNF+ cells in the CA1 field on the 4th day, while the number of BDNF++ neurons remained the same. The observed changes remained on Day 14.The analysis TrkB protein expression in the CA4 field on the 7th day of the post-resuscitation period as revealed by reactivity with anti-TrkB antibody demonstrated a decrease in the number of TrkB– cells as compared to the reference group. By the 14th day, the number of not only TrkB– neurons, but also TrkB+ cells was reduced, while the number of TrkB++ neurons remained at the level of the reference group. There was a decrease in the number of TrkB+ neurons was observed in the CA1 field on the 4th day after resuscitation. On day 7, there was a decreased numbers of both TrkB+ and TrkB–-neurones. The number of TrkB–-neurones remained decreased up to day 14. At that, the number of TrkB++ neurons persisted at the reference level throughout the observation period.Conclusion. The obtained results demonstrate that the resistance of neurons to ischemia-reperfusion is associated with the intracellular expression of BDNF and TrkB proteins. The reduction of the overall density of neurons in the post-resuscitation period was obsereved both in hippocampal fields CA1 and СА4; only cells with minimal and moderate content of the studied proteins died. Neurons with the highest BDNF and TrkB protein content survived.