73 research outputs found
Effect of light-dark changes on the locomotor activity in open field in adult rats and opossums
There have been no reports on how the light-dark changes determine the locomotor activity of animals in the group of high reactivity (HR) and low reactivity (LR). In the present study we have compared selected parameters of the locomotor activity of the HR and the LR groups of the laboratory opossums and Wistar rats during consecutive, light and dark phases in the open field test. Sixty male Wistar adult rats, at an average weight of 350 g each, and 24 adult Monodelphis opossums of both sexes at an average weight of 120 g each were used. The animalsâ activity for 2 h daily between the hours of 17:30 and 19:30, in line with the natural light-dark cycle were recorded and then analysed using VideoTrack ver.2.0 (Vievpoint France). According to our results, we noted that a change of the experimental conditions from light to dark involves an increase in the locomotor activity in rats and opossums of the HR group, while there is no effect on the activity of the rats and opossums in the LR group. Locomotor activity in the HR rats, both in the light and dark conditions is characterised by a consistent pattern of change â higher activity in the first stage of the recording and a slowdown (habituation) in the second phase of the observation. The locomotor activity of the opossum, during both light and dark conditions, was observed to be at a consistently high level compared to the rats
Analysis of calretinin immunoreactivity in the rat piriform cortex after open field stress during postnatal maturation
In our study we used c-Fos protein to identify whether cells containing calretinin
(CR) in the rat piriform cortex are engaged in the response to stress stimulation
and to find out how this expression changes during maturation (PC). The material
consisted of Wistar strain rats of between 0 and 120 days of age divided into
9 groups. Each group consisted of 5 experimental and 3 control rats. Animals
from the experimental groups were exposed to the open field test throughout
10 minutes. The control animals were kept in a home cage. In all age-related
control rats weak c-Fos immunoreactivity was observed. Our results showed
that cells containing c-Fos following an acute open field test were observed
predominantly in layers II and III of the PC just after birth. Their number then
increased and stabilised on P30. We had already observed immature CR-ir cells
at birth. In the 4th week of life these neurons achieved maturity. Their number
increased to P90 and decreased in older animals. CR-ir neurons were localised
mainly in layer II and to a lesser degree in layers III and I of the PC. Double
immunostaining c-Fos/CR revealed that the level of co-localisation was low. Only
small differences were observed between the anterior and posterior parts of the
PC. In the anterior part a higher number of CR-ir neurons was found. The difference
in the level of co-localisation between the anterior and posterior parts was
age-related and differentiated. Our results may suggest that during maturation
CR-ir neurons of the piriform cortex are not the main population engaged in
response to the open field test
Pyruvate dehydrogenase deficiency: morphological and metabolic effects, creation of animal model to search for curative treatment
The main source of energy for brain and other organs is glucose. To obtain energy for all tissue, glucose has to come through glycolysis; then as pyruvate it is converted to acetyl-CoA by pyruvate dehydrogenase complex (PDC) and finally enters citric acid cycle. What happens when one of these stages become disturb? Mutation in genes encoding subunits of PDC leads to pyruvate dehydrogenase deficiency. Abnormalities in PDC activity result in severe metabolic and brain malformations. For better understanding the development and mechanism of pyruvate dehydrogenase deficiency the murine model of this disease has been created. Studies on a murine model showed similar malformation in brain structures as in the patients suffered from pyruvate dehydrogenase deficiency such as reduced neuronal density, heterotopias of grey matter, reduced size of corpus callosum and pyramids. There is still no effective cure for PDC-deficiency. Promising therapy seemed to be ketogenic diet, which substitutes glucose to ketone bodies as a source of energy. Studies have shown that ketogenic diet decreases lactic acidosis and inhibits brain malformations, but not the mortality in early childhood. The newest reports say that phenylbutyrate increases the level of PDC in the brain, because it reduces the level of inactive form of PDH. Experiments on human fibroblast and zebra fish PDC-deficiency model showed that phenylbutyrate is promising cure to PDC-deficiency. This review summarizes the most important findings on the metabolic and morphological effects of PDC-deficiency and research for treatment therapy
The influence of acute and chronic open-field exposure on the hippocampal formation: an immunohistochemical study
The hippocampus plays a role in new learning, memory and emotion and is
a component of the neuroanatomical stress circuit. The structure is involved in
terminating hypothalamic-pituitary-adrenocortical (HPA) axis responses to stress
and attenuates stress responses by shutting off this axis.
The immunoreactivity (-ir) of c-Fos, NGF and its receptor TrkA following acute and
chronic open-field stress were studied in CA1-CA3 and the DG of the hippocampus.
The material consisted of 21 male adult rats divided into three groups: nonstressed
(control) animals and rats exposed to acute (15 min once) and chronic
(15 min daily for 21 days) aversive stimulation (open-field exposure). The brains
were stained with use of immunohistochemical methods for c-Fos, NGF or TrkA.
In the animals exposed to acute open-field stress the number of c-Fos-, TrkAand
NGF-ir cells was higher in all the structures studied than in the control animals.
However they were differentiated only in c-Fos immunoreactivity.
In the rats exposed to chronic open-field stress the number of c-Fos-ir cells in the
structures of the hippocampal formation studied was smaller than in rats exposed
to acute stress and was comparable to that in the control group. No differences
were observed between the groups exposed to acute and chronic stress in the
number of TrkA-ir cells in the structures under investigation. The number of NGF-ir
neurons in CA1 and CA2 was lower after exposure to chronic than after exposure
to acute stress but was still higher than that in the control group.
Our findings indicate that neurons of CA1-CA3 and the DG are engaged in the
stress response after acute as well as chronic open-field exposure. This is probably
related to the important role of the hippocampus in processing new spatial
information as well as in the habituation processes, although these appear to
have different mechanisms
Organisation of the dopamine neuronal subsets within midbrain of the feathertail glider (Acrobates pygmaeus, Acrobatidae, Marsupialia)
The Marsupial feathertail glider has a unique set of morphological, anatomical and behavioural features that make it a promising model for study of primate evolution. Among them it has many locomotor adaptations to arboreal life, such as diagonal gait of movements, gliding, fast climbing and running along branches. These ecological and behavioural specialisations could result in differences in anatomy of the brain systems involved in their integration. It is well acknowledged that dopaminergic neurons are involved in motor control, motivation and cognition. Due to the fact that there are no data on morphological organisation of dopaminergic system in the midbrain of this species, we decided to investigate it using immunohistochemical and quantitative methods. Our study showed that the general distribution and characteristics of the dopaminergic cells within midbrain nuclei of the pygmy acrobat is similar to that in other species, but it lack the substantia nigra compact part â ventral tier and âtailâ of the substantia nigra subnuclei. This study provides the first description of the dopaminergic cells and nuclei in the midbrain of the feathertail glider and we hope it will start interest in the neurobiology of this species
The relationships between neurons containing dopamine and nitric oxide synthase in the ventral tegmental area.
Ventral tegmental area (VTA) is a heterogeneous group of dopaminergic cells which contains interfascicular (IF), parabrachial (PBP) and rostral linear (RLi) nuclei. Neurons of this area are involved in the regulation of motor and motivational aspects of behavior and reveal high neuronal plasticity. Among many various neurotransmitters and neuromodulators, nitric oxide (NO) is localized in this region. In the present study, we investigated morphology and distribution of nitric oxide synthase (NOS)-positive neurons in VTA and their colocalization with dopaminergic neurons. The study was performed on six adult Wistar rats. After perfusional fixation, the brains were cut, immunostained for tyrosine hydroxylase (TH) and NOS and studied by confocal laser microscopy. In each of the three studied nuclei of VTA we investigated three different neuronal populations. Numerous TH-immunoreactive (TH-ir) and NOS-immunoreactive (NOS-ir) neurons are present in the studied region. Among them, a considerable number showed coexistence of both neurotransmitters. The populations of TH-ir and NOS-ir neurons interact with each other as manifested by the presence of NOS-ir endings on TH-ir neurons and vice versa. Taking the above into account, it may be suspected that NO is involved in the modulation of dopaminergic transmission
Cholinergic innervation of parvalbumin- and calbindin-containing neurones in the hippocampus during postnatal development of the rat brain
Immunohistochemical study of the cholinergic innervation of the parvalbuminand
calbindin-containing cells in the hippocampus was conducted on 30 rat
brains of various postnatal ages: P0, P4, P7, P14, P21, P30, P60 and P180.
Sections with double immunostaining for vesicular acetylcholine transporter
(VAChT; the marker of cholinergic cells, fibres and terminals) and parvalbumin
(PV) or calbindin (CB) were analysed using confocal laser-scanning microscope.
Obtained data demonstrate that the pattern of cholinergic innervation of calbindin-
and parvalbumin-immunoreactive hippocampal neurones shows some differences.
During development as well as in the adult species cholinergic terminals
preferentially innervate CB-containing neurones, while cholinergic terminals
on PV-containing cells were observed rarely. Cholinergic endings on the
CB-ir neurones are localised both on their somata and dendrites, whereas on
PV-ir cells they form synaptic contact predominantly with processes. In spite of
the unquestionable cholinergic influence particularly on CB-ir cells, the number
of cholinergic endings suggests that this input seems not to be crucial for the
activity of the studied cell populations
Changes in NGF/c-Fos colocalization in specific limbic structures of juvenile and aged rats after open field stimulation
Changes in NGF release during stressful events have been associated with the
activation of neurons expressing NGF receptors. This study examined the influence
of acute stress-induced stimulation on NGF/c-Fos colocalization in the
following limbic regions: the paraventricular (PV) nucleus of the hypothalamus,
medial (MeA) nucleus of the amygdala, and CA3 hippocampus. Juvenile
(P21) and aged rats (P360) were exposed to a 15-minute acute open field
(OF) test. Double immunofluorescence staining, used to detect NGF-ir and
c-Fos-ir cells, revealed a higher percentage of NGF/c-Fos-ir neurons in the P21
control group than in the P360 control group. Under OF acute stimulation,
a statistically significant (p < 0.05) increase of NGF/c-Fos level in CA3 of juvenile
animals and in PV and CA3 of the aged rats was observed. These observations
indicate that the investigated structures in both age groups show a different
response to acute OF stimulation. Acute OF affects the levels of NGF/c-Fos
more significantly in aged rats
Stress-induced changes of interleukin-1β within the limbic system in the rat
The aim of this study was to investigate the influence of two periods of life,
namely P28 and P360, on the changes in interleukin-1beta (IL-1β) immunoreactivity
(-ir) in the hippocampus (CA1, CA3, DG) and amygdala (central-CeA,
medial-MeA) caused by acute and repeated open field (OF), or by forced swim
(FS) exposition. Rats were divided into groups: non-stressed, exposed to acute
(one-time for 15 min) and chronic stressors (21 days for 15 min daily). We
found IL-1β-ir in the control group to be higher in P360 than in P28. In P28,
under OF and FS exposure, IL-1β-ir in the CeA remained unaltered but increased
in the MeA and in the hippocampus after acute and chronic stress. In P360 no
changes were observed in the IL-1β-ir level after acute and chronic stimulation.
These data demonstrate that only the levels of IL-1β-ir in juvenile rat brains are
affected by FS and OF. Additionally, there was no significant difference between
FS and OF stimulation in IL-1β-ir
Parvalbumin containing neurons of the piriform cortex in open field stress - a developmental study in the rat
In our study we used c-Fos protein (as a marker of cellular activity) to identify
whether cells containing parvalbumin (PV) in the piriform cortex (PC) are engaged
in the response to stress stimulation and to discover how this expression
changes during maturation. The material consisted of Wistar rats of postnatal
(P) ages between 0 and 120 days divided into 9 groups: P0, P4, P7, P10, P14,
P21, P30, P90, P120. Each group consisted of 5 experimental and 3 control
animals. Rats of the experimental groups were exposed to the "open field test"
throughout 10 minutes. The control animals were kept in a home cage. Our
results showed that c-Fos activity in the open field test was observed in layers II
and III of PC after birth. It then increased and stabilised on P30. In the second
week of life PV-positive cells were also observed in those layers. These achieved
maturity in the 4th week of life. After this time basket-like structures appeared
but the level of PV/c-Fos co-localisation was low. Only small differences were
observed between the anterior and posterior parts of PC. In the anterior part
a higher number of PV-positive neurons, neuropil threads, and basket-like structures
and a larger degree of PV/c-Fos co-localisation were observed. Our results
suggested that during maturation PV cells are not directly activated in response
to stress stimuli but PV neurons via their numerous endings influence the activation
of c-Fos-positive cells predominantly in the anterior part of PC
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