Lateral Ventricle Of Rat Brain Research Articles

Вплив комбінованого введення кріоконсервованих мезенхімальних стовбурових клітин та агрегатів нейральних клітин на відновлення рухової активності щурів із інтрацеребральним крововиливом

The effect of implantation of cryopreserved neural cells (NCs) within the neural cells aggregates (NCAs) together with mesenchymal stem cells (MSCs) on the recovery of rat behavioural functions and motor activity after intracerebral hemorrhage (ICH) has been studied. The ICH was simulated by stereotactic injection of collagenase into rat striatum, resulted in loss of sensitivity on the affected side, disorder in motor activity and significant asymmetry of sensory-motor deficits in animals. The cryopreserved NCs (1.5 × 106 cells) within the aggregates and cryopreserved MSCs (1.0 × 106 cells) were implanted into the lateral ventricles of rat brain. A significant recovery of tactile sensitivity, improvement in the skilled tasks performance, as well as a decrease in the asymmetry of sensory-motor deficits in the ICH rats after implantation of cryopreserved NCAs, as well as the combination of the latter with MSCs, have been experimentally established. The implantation of cryopreserved MSCs together with NCAs led to an earlier improvement in behavioural-motor functions in rats with ICH as compared to the animals received the NCAs only. Probl Cryobiol Cryomed 2020; 30(2): 169–177

Neurodegenerative Changes in Rat Brain in Streptozotocin Model of Alzheimer's Disease.

One of the most common models of sporadic form of Alzheimer's disease is injection of streptozotocin into the lateral ventricles of rat brain. In 3 months after this injection, an increase in the expression of astroglia in the corpus callosum and a decrease in the thickness of the corpus callosum and intensity of its staining with luxol fast blue were observed. This can reflect a decrease in the content of myelinated fibers. In layer V of the sensorimotor cortex, intensive degeneration of neurons was revealed. The lateral ventricles were significantly enlarged and the expression of PSA-NCAM protein, a marker of immature neurons, was reduced in subventricular zone, which can be associated with disturbed neurogenesi.

Activation of brain serotonergic system by repeated intracerebral administration of 5-hydroxytryptophan (5-HTP) decreases the expression and activity of liver cytochrome P450

Our recent studies suggest that brain serotonergic system may be involved in the neuroendocrine regulation of cytochrome P450 expression. Intracerebral injection of the serotonergic neurotoxin 5,7-dihydroxytryptamine affected serum hormone concentration and increased the expression and activity of the hormone-dependent isoforms CYP1A1/2, CYP2C11 and CYP3A1. Therefore, the aim of the present study was to investigate the effect of stimulation of brain serotonergic system on cytochrome P450 expression in the liver. The serotonin precursor 5-hydroxytryptophan (5-HTP) was injected for 5 days to the lateral ventricles of rat brain. Afterwards, the brain concentrations of serotonin and its metabolite 5-hydroxyindoleacetic acid 5-HIAA, serum hormone levels and liver cytochrome P450 expression and activity were measured. 5-HTP potently increased the concentration of serotonin and its metabolite 5-HIAA in all the brain structures studied including the hypothalamus. The brain concentrations of noradrenaline or dopamine and its metabolites were not changed in that structure. At the same time, a significant decrease in the serum concentration of the growth hormone and an increase in that of thyroxine were observed. In the liver, the activity of CYP1A, CYP2A, CYP2B, CYP2C11 and CYP3A was diminished, which positively correlated with a decrease in the respective CYP protein levels and a reduction in the mRNA levels of CYP1A2, CYP2A2, CYP2C11, CYP3A1 and CYP3A2. The obtained results provide evidence to prove that brain serotonergic system negatively regulates liver cytochrome P450 expression via endocrine system and suggest mechanisms by which this enzyme may be regulated by drugs with a serotonergic profile such as antidepressants.

Evaluation of behavioral parameters and mortality in a model of temporal lobe epilepsy induced by intracerebroventricular pilocarpine administration

The pilocarpine model of temporal lobe epilepsy (TLE) is a useful tool that is used to investigate the mechanisms underlying the generation and maintenance of seizures. Although this model has been modified significantly to reduce mortality and to promote the appearance of spontaneous recurrent seizures, to date, no detailed evaluation has been performed of the behavioral parameters and mortality in TLE induced by intracerebroventricular pilocarpine administration; therefore, this was the goal of the present study. A single dose of pilocarpine hydrochloride (2.4 mg in a total volume of 2 µl) was injected into the right lateral brain ventricle of rats; the convulsive behavior was rated using the Racine scale and the mortality was analyzed in these animals. We found that 30-90 min after animals received intracerebroventricular pilocarpine injections, 73% developed status epilepticus (SE) with an activity score of 4/5 on the Racine scale. Moreover, these seizures were associated with the propagation of epileptiform activity to different hippocampal regions. Of the animals that developed SE, spontaneous recurrent seizures were observed in 32.5% at different times after SE induction. A 35% mortality rate was observed, which included animals that died during pilocarpine injection and after SE induction. On the basis of these findings, and given the observed latency between the insult (SE induction by pilocarpine injection) and the manifestation of spontaneous recurrent seizures, we propose that this model is a useful tool for basic biomedical research of SE and TLE.

Role of p38 mapk on the down-regulation of matrix metallo-proteinase-9 expression in rat astrocytes

In spite of their pathophysiological importance in neuro-inflammatory diseases, little is known about the signal transduction pathways that lead to the induction of matrix metalloproteinases (MMPs) in the central nervous system. We reported previously that lipopolysaccharide (LPS) induced MMP-9 expression through ERK1/2 pathway in rat primary astrocytes (Glia 41:15-24, 2003). Here, we investigated the role of other MAPK pathways, including p38 and JNK/SAPK, on the regulation of MMP-9 expression in LPS-stimulated rat primary astrocytes. LPS activated both p38 and JNK in astrocytes. Treatment with a specific p38 MAPK inhibitor SB203580, but not JNK inhibitor SP600125, increased the LPS-stimulated MMP-9 expression in a concentration-dependent manner. Anti-inflammatory cytokines, including IFN-gamma and IL-4, activated p38 MAPK and decreased MMP-9 production in LPS-stimulated astrocytes. When p38 MAPK activation was blocked by SB203580, the inhibitory effects of these cytokines on MMP-9 induction were abolished. Finally, direct injection of SB203580 into the lateral ventricle of rat brain increased the LPS-induced MMP-9 activity in cerebral cortex. Altogether, these results suggest that p38 activation down-regulates the inflammatory stimulation-induced overexpression of MMP-9, both in primary astrocytes and in cerebral cortex. The elaborate interplay between ERK1/2 and p38 pathways provides a more sophisticated mechanism for regulating MMP-9 activity in neuroinflammatory diseases.

Bcl-2 enhances neurogenesis and inhibits apoptosis of newborn neurons in adult rat brain following a transient middle cerebral artery occlusion

To determine whether Bcl-2 could influence adult neurogenesis and prevent apoptosis of newborn neurons, we injected Bcl-2 expressing plasmid into the lateral ventricle of rat brain immediately following a 30-min occlusion of the middle cerebral artery (MCAO). We found that Bcl-2 increased neural progenitor cells (BrdU+-DCX+) in the ipsilateral striatum, newborn immature neurons (BrdU+-Tuj-1+) and newborn mature neurons (BrdU+-MAP-2+) in the ipsilateral striatum and frontal cortex at 1 to 4 weeks following MCAO. Bcl-2 overexpression promoted development of newborn neurons into GABAergic and cholinergic neurons in the ipsilateral striatum. Moreover, Bcl-2 significantly decreased the apoptosis of newborn neurons, determined by double staining of Tuj-1 and activated caspase-3 (Tuj-1+-Casp+). These results indicate that overexpression of Bcl-2 in adult rat brain enhances neurogenesis and survival of newborn neurons. Increasing neurogenesis and preventing the death of newborn neuron may be a strategy to aid in the repair of adult brain after stroke.

Active clearance of human amyloid beta 1-42 peptide aggregates from the rat ventricular system.

A major constituent of SP in the brains of Alzheimer's disease is 39-43 amino acid peptide called beta-amyloid peptide (Abeta). Recent data have demonstrated that Abeta has a strong tendency to form insoluble aggregates and that toxic effects of Abeta is based on its aggregation. In the current study, 100 microg of human synthetic Abeta 1-42 (sAbeta 1-42) was infused into the lateral ventricle of rat brain using a short-term infusion model. At 2 or 7 days following the infusion, sAbeta 1-42 was found to form insoluble aggregates, scattering throughout the entire ventricular systems. The sAbeta 1-42 aggregates were partially engulfed by phagocytic cells and deposited at the meningeal vessels or the choroid plexuses. However, these deposits mostly disappeared from the ventricles by 28 days post-infusion. Here, it is reported for the first time that considerable amounts of sAbeta 1-42 are almost cleared from the rat ventricular system by the mononuclear phagocytic system.

Blockade of GABA A receptors disrupts isoperiodic neuronal oscillations in the intergeniculate leaflet of the rat

The intergeniculate leaflet of the thalamus is, besides the suprachiasmatic nucleus of the hypothalamus, the other important neuronal element of the mammalian biological clock. The extracellularly recorded activity of neurons constituting the intergeniculate leaflet, recorded in vivo, is characterized by distinct, very regular ultradian oscillations. The majority of neurons in the circadian timing system are GABAergic. Many, if not all, neurons of the suprachiasmatic nucleus and intergeniculate leaflet contain GABA. In the present study we examined the effects of the GABA A receptor antagonist bicuculline and the chloride channel blocker picrotoxin on isoperiodic neuronal oscillations in the intergeniculate leaflet of rats. We recorded extracellular multiple-unit neuronal activity from the intergeniculate leaflet of anesthetized rats. During the recording of isoperiodic oscillations, bicuculline or picrotoxin were stereotaxically injected at different concentrations into the lateral ventricle of rat brain. In all the experiments, injection of GABA A receptor antagonists transiently disrupted the isoperiodic phasic discharge recorded from the intergeniculate leaflet. These data suggest that GABA A receptors are involved in the generation of ultradian rhythmical neuronal oscillations in rat intergeniculate leaflet.

Ion channels in epithelial cells of the choroid plexus isolated from the lateral ventricle of rat brain

Whole-cell patch clamp methods were used to determine the expression of ion channels in the epithelial cells of choroid plexus isolated from the lateral ventricle of the rat brain. A single population of cells with a mean capacitance of 61.5±1.7 pF was identified in 103 recordings. This value is significantly greater than that measured for cells from the fourth ventricle ( P<0.0l by unpaired t-test), indicating that cells from the lateral ventricle have a greater surface area. Voltage-dependent, outward currents were recorded using a K +-rich electrode solution. These currents were partially inhibited by 10 nM margatoxin or 10 nM dendrotoxin-K and blocked by 5 mM TEA +. An inward-rectifying chloride conductance was observed in K +-free solutions. The relative permeability of this conductance to anions was P I> P Cl> P aspartate. A volume-sensitive anion conductance was observed when cell swelling was induced using a hypertonic electrode solution. The properties of each conductance were similar to conductances previously identified in fourth ventricle choroid plexus cells. Furthermore, there were no significant differences between the magnitudes of any of the conductances in cells from the lateral and fourth ventricle choroid plexus. Thus, the ionic conductances expressed in rat lateral and fourth ventricle choroid plexus are very similar.

Seizure suppression by adenosine-releasing cells is independent of seizure frequency.

Intraventricular cellular delivery of adenosine was recently shown to be transiently efficient in the suppression of seizure activity in the rat kindling model of epilepsy. We tested whether the suppression of seizures by adenosine-releasing grafts was independent of seizure frequency. Adenosine-releasing cells were encapsulated and grafted into the lateral brain ventricle of rats kindled in the hippocampus. During 4 weeks after grafting, electric test stimulations were delivered at a frequency of either once a week or 3 times per week. Seizure activity was evaluated by visual scoring of seizure severity and by the recording of EEGs. Adenosine released from encapsulated cells exerted potent antiepileptic activity for >/=2 weeks. One week after grafting, treated rats displayed a complete protection from clonic seizures, and a protection from focal seizures was observed in the majority of animals. Seizure suppression was accompanied by a reduction of afterdischarges in EEG recordings. The protective efficacy of the grafted cells was the same irrespective of whether electrical test stimulations were delivered 1 or 3 times per week. Rats receiving control grafts continued to display full clonic convulsions. This study demonstrated that the frequency of test stimulations did not influence the seizure-suppressive potential of adenosine-releasing grafts. Thus the local delivery of adenosine is likely to be effective in seizure control over a threefold range of seizure-discharge frequency.

Phosphorylation of Tau, Aβ-Formation, and Apoptosis After In Vivo Inhibition of PP-1 and PP-2A

Chronic inhibition of protein phosphatases 1 and 2A in vivo was induced by infusion of okadaic acid into lateral ventricles of rat brain for up to 4 months. Cytoskeletal pathology, alterations of the amyloid precursor protein, and apoptotic cell death induced by this treatment followed a certain sequence and spatial distribution. Changes in the expression, phosphorylation, and subcellular distribution of neurofilament proteins and tau, as well as first signs of apoptotic cell death, occurred already after about 2 weeks. The distribution of apoptotic cells, however, was different from those revealing a high accumulation of hyperphosphorylated tau, indicating that those cytoskeletal pathology had no obvious sequelae for the viability of these neurones. A continuation of treatment for longer than 2 weeks induced diffuse deposits of both hyperphosphorylated tau and Aβ-amyloid-immunoreactive material in white matter areas that increased in size and number over time. Because τ-phosphorylation is a regulator of the dynamic stability of microtubules, the pathology observed in the present experimental paradigm in the white matter might be viewed as an indication of a disturbed axonal transport. It is hypothesized that perturbations of the axonal transport might also be critically involved in the formation of paired helical filaments and amyloid deposits in Alzheimer’s disease.

Induction of apoptosis in vitro and in vivo by the cholinergic neurotoxin ethylcholine aziridinium

The patterns of cell death induced by the cholinergic neurotoxin ethylcholine aziridinium have been investigated in vitro and in vivo. In vitro, the drug induced apoptosis both in neuronal SK-N-MC cells (human neuroblastoma cells) and in non-neuronal 293 cells (a human embryonic kidney cell line). Apoptosis was developed maximally between 15 and 24 h of exposure to ethylcholine aziridinium (100 μM). At the ultrastrucural level apoptotic cells were characterized by condensation and margination of nuclear chromatin, fragmentation of nuclei and the formation of apoptotic bodies. Inhibition of endonuclease by zinc almost completely prevented the occurrence of apoptosis. The free radical scavenger Tempol effectively inhibited ethylcholine aziridinium-induced apoptosis by 78.6±10.3% ( n=4), whereas cycloheximide and actinomycin D were only partially effective. In vivo, following injection of ethylcholine aziridinium (2 nmol) into the lateral ventricle of rat brain a high incidence of apoptotic cells as verified by in situ tailing was visible in the periventricular tissue. Neurons as well as glia were affected by the neurotoxin. The number of apoptotic cells peaked two to three days after injection of ethylcholine aziridinium and declined thereafter. Up to one week after ethylcholine aziridinium no signs for the induction of apoptosis in the medial septal nucleus were found. This study provides clear evidence that a neurotoxic compound that induces programmed cell death in vitro is likely to have the same capacity in vivo. Yet, in the case of ethylcholine aziridinium, both the in vitro and the in vivo induction of programmed cell death appears to be an additional feature of ethylcholine aziridinium, which may be independent of the well-established degenerative effect of ethylcholine aziridinium on the cholinergic septohippocampal pathway. The present data indicate that ethylcholine aziridinium provides a useful tool to study molecular mechanisms of neuronal apoptosis.

Specific regulation of gene expression in brain by antisense oligodeoxynucleotides

The synthetic oligodeoxynucleotide (ODN) complementary to the normal (sense) mRNA, so-called antisense ODN, has been used to regulate the gene expression in the brain. It has been reported to interfere with transcription, pre-mRNA splicing and translation through at least two mechanisms; i.e., its competition with transcription and protein synthesis machinery or induction of mRNA cleavage. The unmodified antisense ODN was shown to be the RNase activator when it hybridizes with at least four contiguous bases of mRNA. In contrast, the phosphorothioate ODN (S-ODN) is reported to be a less effective activator of RNas II and more resistant to the nuclease attack than unmodified ODN. Because of these properties, S-ODNs are preferentially employed in antisense ODN experiments. When the DNA sequence of the target gene is determined, we can design an antisense ODN that selectively hybridizes with the bases of a nucleic acid (DNA or RNA) related to the target gene. The initial sites of specific binding of most drugs are known to be proteins such as receptors and enzymes. Therefore, the specific modulation of target protein synthesis by the antisense ODN method is quite interesting to the pharmacologist. We have studied the change in the morphine-induced behaviors after the microinjection of antisense S-ODN directed against the m-opioid receptor (MOR) into the periaqueductal gray (PAG) or lateral ventricle of rat brain. We could detect the decrease of the MOR mRNA level in PAG by the RT-PCR method and that in whole brain by the Northern blot technique. Although the antisense ODN method seems to be quite useful for the modulation of a given gene expression, many problems still remain to be elucidated. These include the mechanism of the regulation of a target gene, pharmacokinetics of antisense ODN and toxicity of antisense ODN.

Time course of cholinergic and monoaminergic changes in rat brain after immunolesioning with 192 IgG-saporin

192 IgG-saporin, an immunotoxin targeted at the low affinity NGF receptor, was infused into the lateral ventricle of rat brain. Three days and one week post lesion, choline acetyltransferase activity was markedly decreased in cortex, hippocampus, olfactory bulbs, and septum (brain regions innervated by the cholinergic neurons of the basal forebrain) with no change in cerebellum, striatum or pons. Measurement of monoamine levels revealed increases in HVA, DOPAC and dopamine, primarily in the olfactory bulbs at the 28-day time point only, suggesting a compensation for cholinergic inactivity. High levels of basal forebrain cholinergic lesioning can be obtained with this immunotoxin with minimal or no effects on monoaminergic or other cholinergic systems.

Effects of the Fab fragment of digoxin antibody on the natriuresis and increase in blood pressure induced by intracerebroventricular infusion of hypertonic saline solution in rats.

1. The effects of intravenous injection of Fab fragments of anti-digoxin IgG (Digibind) on the changes in blood pressure, urine volume and urinary sodium excretion after intracerebroventricular infusion of artificial cerebrospinal fluid with normal or high sodium concentration were examined in anaesthetized rats. 2. The biological efficacy of Digibind was confirmed by experiments in vitro and in vivo, which showed that pretreatment with Digibind completely abolished or significantly attenuated the aortic contractile response or pressor response to digoxin in guinea-pigs. 3. Infusion of high-sodium cerebrospinal fluid, but not normal-sodium cerebrospinal fluid, into the lateral brain ventricle of rats caused marked increases in blood pressure, urine volume and urinary sodium excretion. 4. Digibind did not significantly affect the increases in blood pressure, urine volume and urinary sodium excretion caused by intracerebroventricular infusion of high-sodium cerebrospinal fluid. 5. Digoxin-like immunoreactive factor may play a minor role, if any, in central nervous system-induced natriuresis in rats.

Fronto-cortical regulation of β-endorphin actions in the rat

Ablation of the frontal neocortex markedly enhanced the antinociceptive and cataleptic actions of β-endorphin injected into the lateral ventricle of rat brain. This enhanced response was not affected by simultaneous administration of cholecystokinin octapeptide (CCK-8). In sham-operated rats, however, CCK-8 suppressed the effects of β-endorphin in a dose-related manner. Moreover, ablation of a similar amount of occipital neocortex did neither affect β-endorphin actions nor the interactions of CCK-8.

Successful ventricular application of the miniaturized controlled-delivery Accurel technique for sustained enhancement of cerebrospinal fluid peptide levels in the rat

A recently developed small controlled-delivery peptide device has now been further miniaturized (3.5 mm 3 rod) and its action has been tested in vitro and in vivo using vasopressin (VP) as experimental substance. In vitro immersion showed a constant and lasting release of VP for weeks, as had been described for larger devices. By introducing the mini-device into the lateral ventricle of rat brain and by sampling CSF via a permanent cannula in the cisterna magna, a steadily enhanced level of VP could be attained for CSF. These increased levels persisted for one week, but most likely continue for longer periods.

In vivo activity of purified mouse brain renin

Mouse brain renin and kidney renin were purified by a 3-step procedure: acetone powder extraction, Sephadex G-100 chromatography, and blue agarose affinity chromatography. The latter efficiently separated renin from cathepsin D-like acid protease activity. Mouse brain renin had an optimum of enzyme activity of pH 7.0. This differed from mouse kidney renin, which had an optimum at pH 8.5. In vitro, brain renin formed angiotensin I from rat plasma angiotensinogen and had no angiotensinase activity. Mouse brain renin was inhibited by monospecific antibodies raised against pure mouse submandibular gland renin. In vivo activity of the enzyme was tested by injection of brain renin into the lateral brain ventricle of rats. This resulted in the formation of angiostensin I from endogenous brain angiotensinogen, in the stimulation of water uptake, and in a long-lasting increase of arterial blood pressure. The latter could be blocked by the competitive angiotensin II receptor antagonist, saralasin. The results show that brain renin is active under physiological conditions.

Catecholamine formation in brain from phenylalanine and tyrosine— effects of psychotropic drugs and other agents

The present report is a comparative study of phenylalanine and tyrosine as the precursors of cerebral catecholamines. Subcellular fractions of brain regions were incubated with a mixture of ( 14C)phenylalanine and ( 3H)tyrosine for the studies in vitro; the labeled amino acids in solution were injected into the lateral ventricle of rat brain for the experiments in vivo. After the experiments, the ratio of 14C to 3H ( 14C dis./min/ 3H dis./min × 100) in the isolated catecholamines [R(CA)] and tyrosine [R(TY)] was determined. The ratio R(CA)/R(TY) was taken as a measure of the divergence between the isotope ratio in tyrosine and that in the catecholamines. The experiments in vitro indicate that the rate of phenylalanine hydroxylation, the R(CA) value and the R(CA)/R(TY) value may be characteristic properties of specific brain regions. Several physical or chemical agents were found to have profound effects not only on the hydroxylation of phenylalanine but also on the R(CA) and R(CA)/R(TY) values. Lowering the incubation temperature from 37° to 0° decreased the hydroxylation of both the amino acids but favored the relative formation of ( 14C)catecholamines. Lower incubation temperature also favored the formation of the consecutive hydroxylation product ( 14C)catecholamines and very little ( 14C)tyrosine was present in the incubation mixture. Pretreatment of the synaptosomal-mitochondrial enzyme source with any one of several detergents or with hypotonic sucrose almost completely inhibited the hydroxylation of both the substrates. The residual activity of such preparations favors the formation of ( 3H)catecholamines. Time studies at 37° and at 0° indicate that the ratio R(CA)/R(TY) is always greater than unity within the time range of 5–60 min. After incubation of the particulate fraction at 0°, the R(CA) value continues to increase up to 60 min, at which time the formation of ( 14C)catecholamines is about 1·4 times that of ( 3H)catecholamines. The results of incubations at various phenylalanine substrate concentrations show that the value of R(CA)/R(TY) is relatively insensitive to changes in phenylalanine concentration in the presence of a constant level of tyrosine and the values were larger than unity. In vivo, several psychotropic drugs—chlorpromazine, amphetamine, apomorphine and morphine—were observed to either stimulate or inhibit the formation of catecholamines from ( 14C)phenylalanine. In conclusion, our results suggest that: (1) the tyrosine that is formed in vitro from phenylalanine in brain tissue is not freely miscible with the endogenous free tyrosine; (2) the hydroxylation characteristics of the phenylalanine-derived tyrosine may be distinctly different from that of the free endogenous tyrosine; and (3) phenylalanine hydroxylation may be sensitive to some psychotropic drugs in vitro.

Behavioural and biochemical effects of 6-hydroxydopa in rats.

The influence of 6-hydroxydopa (6-HDP) injected into the lateral ventricles of rat brain on the behaviour of animals was examined. The level of noradrenaline (NA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in discrete areas of the brain was also measured.