26 research outputs found
Minocycline but not valproic acid influence the density of NogoA-immunoreactive neurons in the hilus of the dentate gyrus of the rats subjected to intracerebral haematoma
Intracerebral haemorrhage is a devastating neurological disease with high mortality rate and poor prognosis. The most prominent manifestation of the disease arethe movement disorders, but many patients also suffer from cognitive impairment. Taking into account vulnerability of the neurons located within the hilus of the dentate gyrus (HDG) to many brain insults we decided to study the effectof experimentally induced intracerebral haematoma on density of neurons expressing NogoA protein in HDG. In addition, we studied how administration of valproic acid and minocycline, the two drugs generally believed to be neuroprotective agents, influences the density of these neurons. Our study revealed that 4 weeks after intracerebral haematoma induction, minocycline and valproic acid treatment increased the densities of NogoA-ir neurons in the hilus of contralateral dentate gyrus once the data were compared to ipsilateral hemispheres within the same group. The analysis of contralateral hemisphere data, however, revealed increased densities of NogoA-positive neurons in haematoma and valproic acidtreated animals when compared to contralateral hemispheres of control animals.The administration of minocycline was, however, able to alleviate this increase.These changes may influence the haematoma-induced reorganisation of neuronal circuitries in the dentate gyrus
Cholinergic endings on various neurons containing calcium binding proteins and glutamic acid decarboxylase in the hippocampus of the rat
Immunohistochemical study of the cholinergic innervation of the hippocampal cells containing glutamic acid decarboxylase (GAD) and calcium binding proteins: parvalbumin (PV), calbindin D28k (CB) and calretinin (CR) was conducted on 5 adult rat brains. Analysis of sections with double immunostaining for vesicular acetylcholine transporter (VAChT; the marker of cholinergic cells, fibres and terminals) and respectively either GAD or PV, CB, CR, using confocal laser-scanning microscope shows that the intensive cholinergic innervations receive GAD, PV and CB-positive hippocampal cells. Cholinergic afferentations of the CR-positive neurones are considerably fewer
Cholinergic innervation and calretinin-immunoreactive neurones in the hippocampus during postnatal development of the rat brain
Immunohistochemical study of the cholinergic innervation of the hippocampal
calretinin-containing cells was conducted on 28 rat brains of postnatal ages:
P0, P4, P7, P14, P21, P30 and P60. Sections with double immunostaining for vesicular
acetylcholine transporter (VAChT; the marker of cholinergic cells, fibres and
terminals) and calretinin were analysed using confocal laser-scanning microscope.
Obtained data demonstrate that during development as well as in adult species
calretinin-containing neurones in the rat hippocampus form sparse synaptic contact
with VAChT-ir terminals. It seems probable that cholinergic innervation is not
crucial for the functioning of CR-ir cells - probably they remain under the greater
influence of a system other than the cholinergic system
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
Fluoride alters type I collagen expression in the early stages of odontogenesis
Fluoride alters the expression and post-translational modifications of extracellular
matrix proteins in dentin. The aim of our study was to determine the effects
of fluoride on type I collagen expression during the early stages of tooth germ
development in rats. Pregnant dams were divided into three groups and fed
a standard diet. From the fifth day of pregnancy the three groups received tap
water with, respectively, trace amounts of fluoride (C), a low fluoride concentration
(FL) or and a high fluoride concentration (FH). Changes in type I collagen
expression and distribution were evaluated. The expression of type I collagen
was restricted to the extracellular spaces of cells of mesenchymal origin. In the
youngest animals the most intense immunoreactivity for type I collagen was
detected in predentin of the FL group. Although the intensity of immunostaining
increased in proportion to the age of the animals, the largest increase in the
groups investigated was detected in the FL group. We concluded that a low
concentration of fluoride can act as a stimulator of type I collagen deposition in
the extracellular matrix of dentin, while high concentrations of fluoride have an
opposite effect, acting as an inhibitor of type I collagen formation in dentin
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
The immunoreactivity of c-Fos, NGF and its receptor TrkA after open-field exposure in the central and medial nuclei of the rat amygdala
The amygdala is a critical component of the neuroanatomical stress circuit. It
plays a role in the generation of responses to emotional stimuli. The central
(CeA) and medial (MeA) amygdaloid nuclei are implicated in activation of the
hypothalamic-pituitary-adrenocortical (HPA) axis.
The immunoreactivity (-ir) of c-Fos, NGF and its receptor, TrkA, following acute
and chronic open-field stress were studied in the CeA and MeA nuclei of the
amygdala. The material consisted of 21 male adult rats divided into three groups:
non-stressed (control) animals, rats exposed to acute (once only lasting 15 min)
and chronic (15 min daily over 21 days) aversive stimulation (open-field exposure).
The brains were stained with the use of immunohistochemical methods
for c-Fos, NGF or TrkA.
In the control rats c-Fos-, TrkA- and NGF-ir cells were observed in the nuclei
studied, but the quantity varied, being moderate or high (immunoreactive to
TrkA and NGF) or low (immunoreactive to c-Fos).
In the animals exposed to acute open-field stress the number of c-Fos-ir, NGF-ir
and TrkA-ir cells in the nuclei under examination was differentiated but higher
than that in the control animals.
In the animals exposed to chronic open-field stress the number of c-Fos-ir cells
in the nuclei studied was similar and was smaller than those in animals exposed
to acute stress. The number of TrkA-ir neurons was also lower in comparison to
that in animals exposed to acute stress. However, no significant differences in
the number of NGF-ir cells were observed between the groups exposed to acute
and chronic stress.
Diverse expression of c-Fos protein following both acute and chronic stress stimulation
may prove the functional heterogeneity of the amygdaloid nuclei investigated.
The decrease observed in both c-Fos- and TrkA-ir in MeA (only TrkA in
CeA) of animals exposed to chronic stress may indicate the phenomenon of
habituation
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
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
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