Intranasal administration of mitochondria improves spatial memory in olfactory bulbectomized mice

Here, we found that functionally active mitochondria isolated from the brain of NMRI donor mice and administrated intranasally to recipient mice penetrated the brain structures in a dose-dependent manner. The injected mitochondria labeled with the MitoTracker Red localized in different brain regions, including the neocortex and hippocampus, which are responsible for memory and affected by degeneration in patients with Alzheimer's disease. In behavioral experiments, intranasal microinjections of brain mitochondria of native NMRI mice improved spatial memory in the olfactory bulbectomized (OBX) mice with Alzheimer's type degeneration. Control OBX mice demonstrated loss of spatial memory tested in the Morris water maze. Immunocytochemical analysis revealed that allogeneic mitochondria colocalized with the markers of astrocytes and neurons in hippocampal cell culture. The results suggest that a non-invasive route intranasal administration of mitochondria may be a promising approach to the treatment of neurodegenerative diseases characterized, like Alzheimer's disease, by mitochondrial dysfunction.

Proteolytic degradation patterns of the receptor for advanced glycation end products peptide fragments correlate with their neuroprotective activity in Alzheimer's disease models

The receptor for advanced glycation end products (RAGE) plays an essential role in Alzheimer's disease (AD). We previously demonstrated that a fragment (60-76) of RAGE improved the memory of olfactory bulbectomized (OBX) and Tg 5 × FAD mice - animal models of AD. The peptide analog (60-76) with protected N- and C-terminal groups was more active than the free peptide in Tg 5 × FAD mice. This study investigated proteolytic cleavage of the RAGE fragment (60-76) and its C- and N-terminally modified analog by blood serum using HPLC and mass spectrometry. The modified peptide was proteolyzed slower than the free peptide. Degrading the protected analog resulted in shortened fragments with memory-enhancing effects, whereas the free peptide yielded inactive fragments. After administering the different peptides to OBX mice, their performance in a spatial memory task revealed that the effective dose of the modified peptide was five times lower than that of the free peptide. HPLC and mass spectrometry analysis of the proteolytic products allowed us to clarify the differences in the neuroprotective activity conferred by administering these two peptides to AD animal models. The current study suggests that the modified RAGE fragment is more promising for the development of anti-AD therapy than its free analog.

Neuroregeneration: Regulation in Neurodegenerative Diseases and Aging

It had been commonly believed for a long time, that once established, degeneration of the central nervous system (CNS) is irreparable, and that adult person merely cannot restore dead or injured neurons. The existence of stem cells (SCs) in the mature brain, an organ with minimal regenerative ability, had been ignored for many years. Currently accepted that specific structures of the adult brain contain neural SCs (NSCs) that can self-renew and generate terminally differentiated brain cells, including neurons and glia. However, their contribution to the regulation of brain activity and brain regeneration in natural aging and pathology is still a subject of ongoing studies. Since the 1970s, when Fuad Lechin suggested the existence of repair mechanisms in the brain, new exhilarating data from scientists around the world have expanded our knowledge on the mechanisms implicated in the generation of various cell phenotypes supporting the brain, regulation of brain activity by these newly generated cells, and participation of SCs in brain homeostasis and regeneration. The prospects of the SC research are truthfully infinite and hitherto challenging to forecast. Once researchers resolve the issues regarding SC expansion and maintenance, the implementation of the SC-based platform could help to treat tissues and organs impaired or damaged in many devastating human diseases. Over the past 10 years, the number of studies on SCs has increased exponentially, and we have already become witnesses of crucial discoveries in SC biology. Comprehension of the mechanisms of neurogenesis regulation is essential for the development of new therapeutic approaches for currently incurable neurodegenerative diseases and neuroblastomas. In this review, we present the latest achievements in this fast-moving field and discuss essential aspects of NSC biology, including SC regulation by hormones, neurotransmitters, and transcription factors, along with the achievements of genetic and chemical reprogramming for the safe use of SCs in vitro and in vivo.

Effect of Transplantation of Neural Stem and Progenitor Cells on Memory in Animals with Alzheimer's Type Neurodegeneration

The effects of systemic and intracerebral transplantation of human fetal neural stem and progenitor cells were studied on the model of olfactory bulbectomy in mice with developing signs of sporadic Alzheimer's disease. It was found that transplantation of these cells at certain stages of disease development contributed to improvement of spatial memory and preservation of hippocampal neurons in these animals.

Synthetic Fragment of Receptor for Advanced Glycation End Products Prevents Memory Loss and Protects Brain Neurons in Olfactory Bulbectomized Mice

Activation of receptor for advanced glycation end products (RAGE) plays an essential role in the development of Alzheimer's disease (AD). It is known that the soluble isoform of the receptor binds to ligands and prevents negative effects of the receptor activation. We proposed that peptide fragments from RAGE prevent negative effects of the receptor activation during AD neurodegeneration. We have synthesized peptide fragments from surface-exposed regions of RAGE. Peptides were intranasally administrated into olfactory bulbectomized (OBX) mice, which developed some characteristics similar to AD neurodegeneration. We have found that only insertion of fragment (60-76) prevents the memory of OBX mice. Immunization of OBX mice with peptides showed that again only (60-76) peptide protected the memory of animals. Both intranasal insertion and immunization decreased the amyloid-β (Aβ) level in the brain. Activity of shortened fragments of (60-76) peptide was tested and showed only the (60-70) peptide is responsible for manifestation of activity. Intranasal administration of (60-76) peptide shows most protective effect on morpho-functional characteristics of neurons in the cortex and hippocampal areas. Using Flu-(60-76) peptide, we revealed its penetration in the brain of OBX mice as well as colocalization of Flu-labeled peptide with Aβ in the brain regions in transgenic mice. Flu-(60-76) peptide complex with trimer of Aβ was detected by SDS-PAGE. These data indicate that Aβ can be one of the molecular target of (60-70) peptide. These findings provide a new peptide molecule for design of anti-AD drug and for investigation of RAGE activation ways in progression of AD neurodegeneration.

Synthetic Fragments of Receptor for Advanced Glycation End Products Bind Beta-Amyloid 1-40 and Protect Primary Brain Cells From Beta-Amyloid Toxicity

Receptor for advanced glycation end products (RAGE) is involved in the pathogenesis of Alzheimer's disease. We have previously revealed that RAGE fragment sequence (60-76) and its shortened analogs sequence (60-70) and (60-65) under intranasal insertion were able to restore memory and improve morphological and biochemical state of neurons in the brain of bulbectomized mice developing major AD features. In the current study, we have investigated the ability of RAGE peptide (60-76) and five shortened analogs to bind beta-amyloid (Aβ) 1-40 in an fluorescent titration test and show that all the RAGE fragments apart from one [sequence (65-76)] were able to bind Aβ in vitro. Moreover, we show that all RAGE fragments apart from the shortest one (60-62), were able to protect neuronal primary cultures from amyloid toxicity, by preventing the caspase 3 activation induced by Aβ 1-42. We have compared the data obtained in the present research with the previously published data in the animal model of AD, and offer a probable mechanism of neuroprotection of the RAGE peptide.

Effect of weak combined static and extremely low-frequency alternating magnetic fields on spatial memory and brain amyloid-β in two animal models of Alzheimer's disease

Subchronic effect of a weak combined magnetic field (MF), produced by superimposing a constant component, 42 µT and an alternating MF of 0.08 µT, which was the sum of two frequencies of 4.38 and 4.88 Hz, was studied in olfactory bulbectomized (OBE) and transgenic Tg (APPswe, PSEN1) mice, which were used as animal models of sporadic and heritable Alzheimer's disease (AD) accordingly. Spatial memory was tested in a Morris water maze on the following day after completion of training trials with the hidden platform removed. The amyloid-β (Aβ) level was determined in extracts of the cortex and hippocampus of mice using a specific DOT analysis while the number and dimensions of amyloid plaques were detected after their staining with thioflavin S in transgenic animals. Exposure to the MFs (4 h/day for 10 days) induced the decrease of Aβ level in brain of OBE mice and reduced the number of Aβ plaques in the cortex and hippocampus of Tg animals. However, memory improvement was revealed in Tg mice only, but not in the OBE animals. Here, we suggest that in order to prevent the Aβ accumulation, MFs could be used at early stage of neuronal degeneration in case of AD and other diseases with amyloid protein deposition in other tissues.

Molecular Mechanisms Underlying Neuroprotective Effect of Intranasal Administration of Human Hsp70 in Mouse Model of Alzheimer's Disease

Heat shock protein 70, encoded by the HSPA1A gene in humans, is a key component of the machinery that protects neuronal cells from various stress conditions and whose production significantly declines during the course of aging and as a result of several neurodegenerative diseases. Herein, we investigated whether sub-chronic intranasal administration of exogenous Hsp70 (eHsp70) exerts a neuroprotective effect on the temporal cortex and areas of the hippocampus in transgenic 5XFAD mice, a model of Alzheimer's disease. The quantitative analysis of neuronal pathologies in the compared groups, transgenic (Tg) versus non-transgenic (nTg), revealed high level of abnormalities in the brains of transgenic mice. Treatment with human recombinant Hsp70 had profound rejuvenation effect on both neuronal morphology and functional state in the temporal cortex and hippocampal regions in transgenic mice. Hsp70 administration had a smaller, but still significant, effect on the functional state of neurons in non-transgenic mice as well. Using deep sequencing, we identified multiple differentially expressed genes (DEGs) in the hippocampus of transgenic and non-transgenic mice. Furthermore, this analysis demonstrated that eHsp70 administration strongly modulates the spectrum of DEGs in transgenic animals, reverting to a pattern similar to that observed in non-transgenic age-matched mice, which included upregulation of genes responsible for amine transport, transmission of nerve impulses and other pathways that are impaired in 5XFAD mice. Overall, our data indicate that Hsp70 treatment may be an effective therapeutic against old age diseases of the Alzheimer's type.

Molecular and Cellular Mechanisms of Sporadic Alzheimer's Disease: Studies on Rodent Models in vivo

In this review, recent data are presented on molecular and cellular mechanisms of pathogenesis of the most widespread (about 95%) sporadic forms of Alzheimer's disease obtained on in vivo rodent models. Although none of the available models can fully reproduce the human disease, several key molecular mechanisms (such as dysfunction of neurotransmitter systems, especially of the acetylcholinergic system, β-amyloid toxicity, oxidative stress, neuroinflammation, mitochondrial dysfunction, disturbances in neurotrophic systems) are confirmed with different models. Injection models, olfactory bulbectomy, and senescence accelerated OXYS rats are reviewed in detail. These three approaches to in vivo modeling of sporadic Alzheimer's disease have demonstrated a considerable similarity in molecular and cellular mechanisms of pathology development. Studies on these models provide complementary data, and each model possesses its specific advantages. A general analysis of the data reported for the three models provides a multifaceted and the currently most complete molecular picture of sporadic Alzheimer's disease. This is highly relevant also from the practical viewpoint because it creates a basis for elaboration and preclinical studies of means for treatment of this disease.

Interplay between recombinant Hsp70 and proteasomes: proteasome activity modulation and ubiquitin-independent cleavage of Hsp70

The heat shock protein 70 (Hsp70, human HSPA1A) plays indispensable roles in cellular stress responses and protein quality control (PQC). In the framework of PQC, it cooperates with the ubiquitin-proteasome system (UPS) to clear damaged and dysfunctional proteins in the cell. Moreover, Hsp70 itself is rapidly degraded following the recovery from stress. It was demonstrated that its fast turnover is mediated via ubiquitination and subsequent degradation by the 26S proteasome. At the same time, the effect of Hsp70 on the functional state of proteasomes has been insufficiently investigated. Here, we characterized the direct effect of recombinant Hsp70 on the activity of 20S and 26S proteasomes and studied Hsp70 degradation by the 20S proteasome in vitro. We have shown that the activity of purified 20S proteasomes is decreased following incubation with recombinant human Hsp70. On the other hand, high concentrations of Hsp70 activated 26S proteasomes. Finally, we obtained evidence that in addition to previously reported ubiquitin-dependent degradation, Hsp70 could be cleaved independent of ubiquitination by the 20S proteasome. The results obtained reveal novel aspects of the interplay between Hsp70 and proteasomes.

Beta-Amyloid and Tau-Protein: Structure, Interaction, and Prion-Like Properties

During the last twenty years, molecular genetic investigations of Alzheimer's disease (AD) have significantly broadened our knowledge of basic mechanisms of this disorder. However, still no unambiguous concept on the molecular bases of AD pathogenesis has been elaborated, which significantly impedes the development of AD therapy. In this review, we analyze issues concerning processes of generation of two proteins (β-amyloid peptide and Tau-protein) in the cell, which are believed to play the key role in AD genesis. Until recently, these agents were considered independently of each other, but in light of the latest studies, it becomes clear that it is necessary to study their interaction and combined effects. Studies of mechanisms of toxic action of these endogenous compounds, beginning from their interaction with known receptors of main neurotransmitters to specific peculiarities of functioning of signal intracellular pathways upon development of this pathology, open the way to development of new pharmaceutical substances directed concurrently on key mechanisms of interaction of toxic proteins inside the cell and on the pathways of their propagation in the extracellular space.

The Fate of Exogenous Human HSP70 Introduced into Animal Cells by Different Means

Over the last decade, it has become evident that in mammals, including humans, heat shock protein 70 (HSP70), apart from its intracellular localization, is found in extracellular space, where it may execute various protective functions. Furthermore, the upregulation of HSP70 family members can be beneficial in the prevention and treatment of various human neurodegenerative diseases and cancer. Here, we demonstrate that recombinant human HSP70 after intranasal administration can penetrate various brain regions of mice in its native form and subsequently undergo rapid degradation. It was also shown that labeled HSP70 added to culture medium of different human and mouse cell lines enters the cells with strikingly different kinetics, which positively correlates with the basic levels of membrane bound Toll-like receptors (TLR) that are characteristic of these cell lines. HSP70 administration does not significantly modulate the level of TLR expression at the protein or RNA level. The degradation of the introduced recombinant HSP70 after entering the cells is likely proteasome-dependent and varies significantly depending on the cells type and origin. These results should be considered when developing HSP70-based therapies.

Therapeutic effect of mesenchymal multipotent stromal cells on memory in animals with Alzheimer-type neurodegeneration

Transplantation of human mesenchymal multipotent stromal cells improved spatial memory in bulbectomized mice with Alzheimer-type neurodegeneration. The positive effect was observed in 1 month after intracerebral transplantation and in 3 months after systemic injection of mesenchymal multipotent stromal cells. No cases of malignant transformation were noted. These findings indicate prospects of using mesenchymal multipotent stromal cells for the therapy of Alzheimer disease and the possibility of their systemic administration for attaining the therapeutic effect.

[Immunization witha synthetic fragment 155-164 of neurotrophin receptor p75 prevents memory loss and decreases beta-amyloid level in mice with experimentally induced Alzheimer's disease]

Neurotoxic beta-amyloid peptide plays an important role in the pathology of Alzheimer's disease. In aggregated form it binds to several proteins on the surface of the brain cells leading to their death. p75 receptor in- volved in supporting of cell balance is one of the targets for toxic beta-amyloid. We proposed that induction of antibodies against potential binding sites of p75 with beta-amyloid can be a promising approach towards new drug development for Alzheimer's disease therapy. Four potentially immunoactive fragments of p75 were chosen and chemically synthesized. Investigation of immunoprotective effect of the peptide fragments carried out in mice with experimentally induced form of Alzheimer's disease helped to reveal two fragments effectively preserving murine memory from impairment. Results obtained by ELISA biochemical analysis showed that only immunization with fragment p75 155-164 led to significant decrease in beta-amyloid level in the brain of the experimental mice. Thus, immunization with both fragments of p75 receptor is believed to be an effective tool for the development of new drugs against Alzheimer's disease.

[Mechanism of action of combined extremely weak magnetic field on aqueous solution of amino acid]

The fundamental physical mechanisms of resonance action of an extremely weak (40 nT) alternating magnetic field at the cyclotron frequency combined with a weak (40 μT) static magnetic field, on living systems are analyzed in the present work. The experimental effects of such sort of magnetic fields were described in different papers: the very narrow resonant peaks in electrical conductivity of the aqueous solutions in the in vitro experiments and the biomedical in vivo effects on living animals of magnetic fields with frequencies tuned to some amino acids. The existing experimental in vitro data had a good repeatability in different laboratories and countries. Unfortunately, for free ions such sort of effects are absolutely impossible because the dimensions of an ion rotation radius should be measured by meters at room temperature and at very low static magnetic fields used in all the above experiments. Even for bound ions these effects should be also absolutely impossible from the positions of classic physics because of rather high viscosity of biological liquid media (blood plasma, cerebrospinal liquid, cytoplasm). Only modern quantum electrodynamics of condensed media opens the new ways for solving these problems. The proposed article is devoted to analysis of quantum mechanisms of these effects.

Therapeutic effect of exogenous hsp70 in mouse models of Alzheimer's disease

Brain deterioration resulting from "protein folding" diseases, such as the Alzheimer's disease (AD), is one of the leading causes of morbidity and mortality in the aging human population. Heat shock proteins (Hsps) constitute the major cellular quality control system for proteins that mitigates the pathological burden of neurotoxic protein fibrils and aggregates. However, the therapeutic effect of Hsps has not been tested in a relevant setting. Here we report the dramatic neuroprotective effect of recombinant human Hsp70 in the bilateral olfactory bulbectomy model (OBX mice) and 5XFAD mouse models of neurodegeneration. We show that intranasally-administered Hsp70 rapidly enters the afflicted brain regions and mitigates multiple AD-like morphological and cognitive abnormalities observed in model animals. In particular, in both cases it normalizes the density of neurons in the hippocampus and cortex which correlates with the diminished accumulation of amyloid-β (Aβ) peptide and, in the case of 5XFAD mice, reduces Aβ plaque formation. Consistently, Hsp70 treatment also protects spatial memory in OBX and 5XFAD mice. These studies demonstrate that exogenous Hsp70 may be a practical therapeutic agent for treatment of neurodegenerative diseases associated with abnormal protein biogenesis and cognitive disturbances, such as AD, for which neuroprotective therapy is urgently needed.

Immunization with either prion protein fragment 95-123 or the fragment-specific antibodies rescue memory loss and neurodegenerative phenotype of neurons in olfactory bulbectomized mice

Epidemiological studies demonstrated association between head injury (HI) and the subsequent development of Alzheimer's disease (AD). Certain hallmarks of AD, e.g. amyloid-β (Aβ) containing deposits, may be found in patients following traumatic BI (TBI). Recent studies uncover the cellular prion protein, PrP(C), as a receptor for soluble polymeric forms of Aβ (sAβ) which are an intermediate of such deposits. We aimed to test the hypothesis that targeting of PrP(C) can prevent Aβ related spatial memory deficits in olfactory bulbectomized (OBX) mice utilized here to resemble some clinical features of AD, such as increased level of Aβ, memory loss and deficit of the CNS cholin- and serotonin-ergic systems. We demonstrated that immunization with the a.a. 95-123 fragment of cellular prion (PrP-I) recovered cortical and hippocampus neurons from OBX induced degeneration, rescued spatial memory loss in Morris water maze test and significantly decrease the Aβ level in brain tissue of these animals. Affinity purified anti-PrP-I antibodies rescued pre-synaptic biomarker synaptophysin eliciting similar effect on memory of OBX mice, and protected hippocampal neurones from Aβ25-35-induced toxicity in vitro. Immunization OBX mice with a.a. 200-213 fragment of cellular prion (PrP-II) did not reach a significance in memory protection albeit having similar to PrP-I immunization impact on Aβ level in brain tissue. The observed positive effect of targeting the PrP-I by either active or passive immunization on memory of OBX mice revealed the involvement of the PrP(C) in AD-like pathology induced by olfactory bulbectomy. This OBX model may be a useful tool for mechanistic and preclinical therapeutic investigations into the association between PrP(C) and AD.

[New approaches to the immunotherapy of Alzheimer's disease with the synthetic fragments of alpha7 subunit of the acetylcholine receptor]

The effect of immunization with the synthetic fragments of the alpha7 subunit of the acetylcholine nicotine receptor on the spatial memory of mice subjected to olfactory bulbectomy, which causes the development of the neuro-degenetrative disease of Alzheimer's type, was studied. Mice of the NMRI line were immunized with the KLH conjugates of two peptide fragments of the N-terminal fragment of the alpha7 subunit extraxcellular fragment, subjected to olfactory bulbectomy to cause the development of the neurodegenetrative disease of Alzheimer's type, and then the state of the spartial memory was evaluated. It was shown that 20% of bulbectomized mice immunized with the N-terminal 1-23 fragment exhibited good spatial memory after training. Immunization with the peptide construct (159-167)-(179-188) consisting of two hydrophilic exposed regions of alpha7-subunit induced good spatial memory in 50% of bulbectomized mice, while in the control group, which received only KLH, none of the animals were educated. Thus, the development of immunotherapy with peptide (159-167)-(179-188) seems to be a promising approach to prophylaxis and treatment of Alzheimer's disease.

[Induction of antibodies to particular sites of the alpha7 subunit of the nicotinic acetylcholine receptor in mice of different lines]

Five synthetic fragments of the N-terminal domain of the alpha7 subunit of the human nicotinic acetylcholine receptor (alpha7 nAChR) that correspond to theoretically calculated B epitopes and T helper epitopes of the protein and contain from 16 to 29 amino acid residues were tested for the ability to stimulate the formation of antibodies in mice of three lines having H-2d, H-2b, and H-2k haplotypes of the major histocompatibility complex. It was shown that, in the free (unconjugated) form, all the peptides stimulate the formation of antibodies at least in one mouse line. Most of the peptides induced the formation of antibodies in BALB/c mice (haplotype H-2d); therefore, more detailed studies were carried out on these animals. The free peptides and/or their conjugates with keyhole limpet hemocyanin were demonstrated to be capable of stimulating the formation in BALB/c mice of antibodies that bind to the recombinant extracellular N-terminal domain of (alpha7 nAChRalpha). The epitope mapping of antipeptide antibodies carried out using truncated fragments helped reveal antipeptide antibodies to four regions of the alpha7 subunit: 1-23, 98-106, 159-168, and 173-188 (or 179-188).

[Morpho-functional state of neurons in temporal cortex and hippocampus in bulbectomized rats with different level of spatial memory]

Olfactory bulbs removal (bulbectomy) induced neurodegeneration in the brain of mice and guinea pigs which, according to its morphological, biochemical and behavioral features was simular to manifestations of Alzheimer's disease. In the present work long-term effects of bulbectomy were examined in rats. It was shown that 1 year after the operation bulbectomized animals (BEA) could be divided into two subgroups: animals with good results of testing spatial memory(BEA-GM), and with poor memory (BEA-PM). The quantitative analysis of neurons morpho-functional state has shown more expressed pathological changes (an increase in the number of cells with pyknosis, karyolysis, cytolysis, and vacuolization) in neurons of temporal cortex and hippocampus in BEA-PM as compared to those in BEA-GM. In both animal groups the reduction of cellular density was marked in the cortex. According to the content of brain beta-amyloid the groups of experimental animals were distributed in the following order: BEA-PM>BEA-GM>control group of sham-operated rats. The results indicate the long-term changes of morpho-functional state of neurons in the brain of BEA, which correlated with the level of their spatial memory.

[Noopept improves the spatial memory and stimulates prefibrillar beta-amyloid(25-35) antibody production in mice]

The effects of the novel proline-containing nootropic and neuroprotective dipeptide noopept (GVS-111, N-phenylacetyl-L-prolylglycine ethyl ester) were studied on NMRI mice upon olfactory bulbectomy, which had been previously shown to imitate the main morphological and biochemical signs of Alzheimer's disease (AD). The spatial memory was assessed using the Morris (water maze) test; the immunological status was characterized by ELISA with antibodies to prefibrillar beta-amyloid(25-35), S100b protein, and protofilaments of equine lysozyme, which are the molecular factors involved in the pathogenesis of AD. The control (sham-operated) animals during the Morris test preferred a sector where the safety platform was placed during the learning session. Bulbectomized animals treated with saline failed to recognize this sector, while bulbectomized animals treated with noopept (0.01 mg/kg for 21 days) restored this predominance, thus demonstrating the improvement of the spatial memory. These animals also demonstrated an increase in the level of antibodies to beta-amyloid(25-35)--the effect, which was more pronounced in the sham-operated than in bulbectomized mice. The latter demonstrated a profound decrease of immunological reactivity in a large number of tests. Noopept, stimulating the production of antibodies to beta-amyloid(25-35), can attenuate the well-known neurotoxic effects of beta-amyloid. The obtained data on the mnemotropic and immunostimulant effects noopept are indicative of good prospects for the clinical usage of this drug in the therapy of patients with neurodegenerative diseases.

Cholinopositive effect of dilept (neurotensin peptidomimetic) as the basis of its mnemotropic effect

Dilept eliminated learning disturbances in the extrapolation avoidance test, caused by chronic injections of scopolamine alone and in combination with madopar to rats. Dilept improved the dynamics of training and parameters of spatial memory impaired by olfactory bulbectomy (operation causing hypofunction of the central cholinergic system). The detected choline-positive effect of dilept together with pronounced dopaminergic activity necessitate its further development as a drug effective in positive and negative symptoms of schizophrenia and psychotic manifestations of Alzheimer's disease.

Increased level of beta-amyloid in the brain of bulbectomized mice

Six weeks after bilateral olfactory bulbectomy, a peptide with molecular weight of 4 kD was revealed in extracts of the neocortex and hippocampus from mice. Using monoclonal antibodies 4G8, this peptide was identified as beta-amyloid. Its level was significantly higher in the bulbectomized animals than in sham-operated mice. The bulbectomized mice displayed sharp impairment in spatial memory when tested in the Morris water maze. The results suggest that bulbectomy initiates in the brain a pathological process similar to human Alzheimer's disease in location, biochemistry, and behavioral manifestations.

[Immunodepressed status of mice after bulbectomy]

We studied the immune response in lymphoid cells of mice subjected to bilateral olfactory bulbectomy in comparison with sham-operated animals 1.5 and 13 months after surgery. The concentration of tumor necrosis factor decreased threefold in the peripheral blood of bulbectomized mice 1.5 months after surgery. Signs of immunodepression were also observed 13 months after surgery: suppression of mitogen-stimulated proliferation of T and B lymphocytes in the spleen, inhibition of synthesis of tumor necrosis factor in peritoneal macrophages and splenocytes, and decreased macrophage NO production. According to the immune status indices and our previous data on behavioral, biochemical, and morphological changes induced in bulbectomized mice, they have common symptoms with the Alzheimer's disease. This allows us to consider such animals as a model of sporadic form of this disease rather than of a depression.

Morphofunctional Changes in Neurons in the Temporal Cortex of the Brain in Relation to Spatial Memory in Bulbectomized Mice After Treatment with Mineral Ascorbates

The effects of an antioxidant mixture of mineral ascorbates (MA) on the state of neurons in the temporal area of the cortex and the behavior of mice subjected to bulbectomy (BE) were studied; these mice, as demonstrated previously, are characterized by deficiency of spatial memory and the development of a neurodegenerative process in brain structures showing pathological changes in Alzheimer's disease. One month after BE, there were abnormalities in the cytoarchitectonics of the temporal area of the cortex, with loss of clarity of the boundaries between its layers because of dystrophy of pyramidal neurons and foci of loss of these cells. There were sharp increases in the numbers of neurons showing pyknosis, karyolysis, and vacuolysis on the background of decreases in neuronal density. Three weeks of treatment by addition of MA to the diet prevented the degradation of spatial memory in mice after BE and protected neurons in the temporal area of the cortex from degenerative changes. These results provide evidence for the possibility of prophylaxis of neurodestructive changes of the Alzheimer's type.

[Morpho-functional changes of neurons in temporal cortex in comparison with spatial memory in bulbectomized mice after treatment with minerals and ascorbates]

The effect of antioxidant mixture of mineralascorbates (MA) on the status of neurons of brain temporal cortex and behavior of mice after olfactory bulbectomy (BE) was studied, as it was previously shown by us that these animals were characterized by a deficit of spatial memory and development of neurodegenerative process in brain structures, which are affected by Alzheimer disease. Disorganization of cytoarchitectonics of temporal cortex with the deletion of its layers as a result of dystrophy of pyramidal neurons and foci of their complete disappearance were shown 1 month after BE. The increased number of neurons with the phenomena of karyopyknosis, karyolysis and vacuolysis was observed with a concomitant reduction in neuronal density. Addition of MA to the diet for three weeks prevented the development of deterioration of spatial memory in mice after BE and protected the neurons of brain temporal cortex from the degenerative changes. The results obtained suggest the possibility of realization of prophylaxis aimed at the prevention of the development of Alzheimer-type neurodestructive processes.

Lesioning of spatial memory in mice treated with agroclavin

This report presents results obtained from studies of the mnemotropic activity of the ergot alkaloid agroclavin. The effects of this substance were studied at concentrations of 1, 10, 25, 50, and 200 microg/kg on the learning and retention of a spatial habit in a Morris water maze. These doses of agroclavin had no effect on the process of formation of the spatial habit, but sharply disturbed retention of the habit. A long-lasting effect of memory trace disturbance was seen over a period of 48 h after dosage. On retraining, animals showed no delayed effects with agroclavin on learning a new spatial habit. The possible mechanisms for the effect of agroclavin on memory are discussed.

Organization of working memory processes in monkeys: the effects of a dopamine receptor agonist

The effects of the dopamine receptor agonist agroclavin on cognitive processes associated with mechanisms of visual recognition and long-term and working (short-term) memory were studied in delayed visual differentiation and delayed spatial selection tasks in monkeys (rhesus macaques). Measurements made before and after p.o. pharmacological treatment with this agent were used to identify the p.o. dose (5 mg/kg) inducing a significant effect. The psychotropic effect of agroclavin, which induced cognitive dysfunction, was present in all the monkeys studied to one extent or another. Behavioral criteria were: the probability of correct solutions of the visual differentiation task, the probability of refusals to resolve the task, and the time taken for correct motor responses. Despite individual differences in these behavioral characteristics in monkeys, significant changes due to agroclavin were consistently evident in all animals. There was a reduction in the probability of correct solutions, due to worsening of the characteristics of short-term memory; most monkeys showed increases in the numbers of refusals to solve tasks and increases in the time for correct motor responses during these solutions. In fact, all monkeys showed no increases in the number of erroneous solutions in visual differeniation and spatial selection tasks without delays, though in most cases there were increases in the time taken for correct motor reactions and the number of refusals to solve tasks. Data were obtained indicating that the effect of agroclavin was not uniform with respect to different types of visual information. The possible structural-functional organization of processes underlying working memory is discussed on the basis of the conclusion that the behavioral characteristics studied here reflect different components of cognitive processes realized by structures with different functional properties and different locations.

[Destruction of amyloid beta-protein by exposure to weak magnetic fields]

It was found that weak magnetic fields (constant 42 microT; variable 0.05 microT; summation of frequencies in the range of 3.58-4.88 Hz) substantially (approximately fourfold) accelerate the hydrolysis of the amyloid beta-protein in aqueous solution. A region of the amyloid beta-protein most sensitive to the action of weak magnetic fields was determined. It is localized between Asp and Ser amino acid residues in positions 7 and 8 of the peptide sequence. It is in this region that the hydrolysis of the molecule of the amyloid beta-protein by the action of magnetic fields predominantly takes place.

Mechanisms of amnestic effect of ergot alkaloid agroclavin

Neurochemical mechanisms of the effect of agroclavin on spatial memory in the Morris water maze in mice were studied by analyzing the effect of neurotransmitter receptor ligands on the amnestic effect of this alkaloid. D1-receptor agonist SKF-38393 and calcium channel blockers verapamil and nimodipine abolished the negative effect of agroclavin on spatial memory. The role of intracellular calcium in the mechanisms of amnestic effect of agroclavin is discussed.

[Disruption of spatial memory in mice exposed to agroclavine]

The results of the study of the mnemotropic activity of the ergot alkaloid agroclavine are presented. Effects of this substance administered in doses of 1, 10, 25, 50, and 200 micrograms/kg on learning and spatial memory were studied in a Morris water maze. Agroclavine had no effect on learning but sharply impaired the retention. This memory impairment persisted for 48 h after the agroclavine administration. Agroclavine treatment did not affect the ability of mice to learn and retain a new skill. Possible mechanisms of the agroclavine effect on memory are discussed.

[Selection of ergot alkaloid producers by induced mutagenesis]

Using the induced mutagenesis technique, A series of genetically modified Claviceps sp. VKM F-2609 strains that display high levels of agroclavine and elymoclavine synthesis were selected by induced mutagenesis. Compared to the parent strain, c106 displayed a 40-fold higher level of agroclavine synthesis, and c66 displayed an eightfold higher level of elymoclavine synthesis. The levels of synthesis of other alkaloids were decreased in these strains. The effects of various carbohydrates on the strain growth and ergot alkaloid biosynthesis was then investigated in both the parent strain and c106. The largest amount of agroclavine was synthesized by c106 strain growing on a medium with maltose.

[Effect of a dopamine agonist on working memory in monkeys]

Prior to and after pharmacological effect of Agroclavine (a dopamine receptors' agonist) following its per os administration, its optimal dose (5 mg/kg) for cognitive processes was established in monkeys. Psychotropic effect of Agroclavine resulting in cognitive dysfunction manifested itself to a greater of lesser extent in all the experimental animals. Correctness of visual differentiation, probability of refusal to solve a task, time of a correct motor response were assumed as the behavioural criteria. In fact, all the animals revealed absence of any increase in the number of wrong solutions in visual differentiation or spatial choice, although the time of correct morot response and the number of refusal to solve the task mostly increased. The Agroclavine effect was found to be rather variable in respect to different types of visual information. A possible structural-functional organisation of the working memory processes is discussed.

[Modified water maze for studying spatial memory of rats]

A method for evaluation of impairments of spatial memory in rats is put forward. Sensitivity of the advanced method based on the principles of Morris' water maze was compared with that of the classic prototype. Efficiency of the advanced method was assessed by dose- and time-dependent effects of agroclavine on the spatial memory of rats. Agroclavine (10 micrograms/kg) was shown to produce spatial memory impairment in rats. The obtained results also indicate that the modernized maze is more sensitive in revealing impairments of the spatial memory in rats than the classic water maze.

[Effect of agroclavine on conditional active and passive avoidance responses in mice]

The effect of agroclavine, a compound belonging to the group of ergot alkaloids, on the active and passive avoidance habit learning and retrieval in mice was studied. It was found that agroclavine violated the retention of both habit types, while changing neither the learning rate nor the retrieval efficacy. The drug effect was retained for three weeks after administration. It was suggested that agroclavine probably disturbs the short- to long-term memory transformation.

The state of cholinergic structures in forebrain of bulbectomized mice

The effects of bulbectomy on the state of basal forebrain cholinergic structures and spatial memory in Morris water maze were studied. Immunostaining with polyclonal antibodies to choline acetyltransferase AB144P revealed decreased density of immunoreactive cells in the horizontal limb of the diagonal band of Broca (55% of control), basal magnocellular preoptic nucleus (58.9%), and the caudate nucleus-putamen complex (68.2%). No significant changes in the vertical limb of the diagonal band of Broca and globus pallidus were observed. These findings and published data allow us to assume that pathology of the olfactory bulb can underlie memory impairment during Alzheimer's disease associated with dysfunction of acetylcholine-synthesizing structures in the forebrain.

[Cellular content of mixed saliva sediment in patients with chronic mucosal inflammation]

A comparative analysis was made of the saliva sediment cell composition in healthy patients and patients with chronic mucosal inflammation. Migration of leucocytes to the oral cavity was registered in patients with chronic inflammatory processes. A reliable increase in the number of epithelial cells with high degree of destruction was determined in saliva in addition to the appearance of cubic epithelial cells. These results indicate certain violation of epithelial reparation. It is proposed to use a quantitative analysis of saliva sediment for estimating functional conditions of mucosa.

Bulbectomy-induced loss of raphe neurons is counteracted by antidepressant treatment

1. Bilateral olfactory bulb ablation was performed in C57B1/6j mice (C57). Separate groups of bulbectomized mice were treated with either antidepressants (trazodone, 20 mg/kg i.p., or amitriptyline, 20 mg/kg i.p.) or saline daily for 14 consecutive days starting 14 days after surgery. 2. Celloidine-imbedded 10 microns-thick brain sections containing the nucleus raphe dorsalis (NRD) or locus coeruleus (LC) were stained for Nissl, and the number of functional and pyknotic cells was counted out of 500 total cell count for each animal in every experimental group: sham-operated, bulbectomized treated with saline or one of the two antidepressants. 3. Bulbectomy produced a significant 4 times increase in the proportion of pyknotic cells in NRD as compared to sham-operated control. Both antidepressants reversed the effect bringing the number of pyknotic cells to control level. The proportion of pyknotic cells in LC was also slightly increased (61%) in the bulbectomized mice, but only amitriptyline was able to reverse the effect. 4. Widespread degeneration of the neurons in NRD caused by bulbectomy may be involved in the serotonergic component of the bulbectomy syndrome. The ability of antidepressants to diminish bulbectomy-induced loss of NRD neurons may underlie their restorative effect on the behavior and neurochemical characteristics of bulbectomized animals.

Antidepressants suppress bulbectomy-induced augmentation of voluntary alcohol consumption in C57B1/6j but not in DBA/2j mice

Bulbectomy has been previously shown to produce the specific antidepressant-sensitive syndrome in C57Bl/6j, but not DBA/2j mice. The present study examined the effect of the depression on voluntary alcohol consumption. Alcohol consumption and alcohol preference (% of alcohol solution in total liquid) in a free-choice, two-bottle situation was measured in C57BL/6j and DBA/2j mice after sham-operation, anosmia with 10% ZnSO4, or bulbectomy. Both anosmic and bulbectomized mice of both strains consumed more alcohol and showed stronger preference for alcohol than sham-operated mice. In DBA/2j mice both operations altered alcohol consumption of the whole population, and the effect of bulbectomy was stronger. In C57Bl/6j mice bulbectomy and, to a less degree, anosmia seemed to affect predominantly the low-drinking animals. Chronic treatment with antidepressants amitriptyline (20 mg/kg), trazodone (20 mg/kg), and imipramine (10 mg/kg), did not change alcohol consumption in sham-operated C57Bl/6j mice. In anosmic mice antidepressants decreased alcohol preference, but only amitryptyline also decreased alcohol consumption. All antidepressants decreased both alcohol consumption and preference in bulbectomized C57Bl/6j mice. In DBA/2j mice antidepressant treatment either increased, or did not alter alcohol consumption and preference in all groups, though the effects varied among individual antidepressants. The possible connection between the bulbectomy-induced behavioral syndrome and elevated ethanol consumption in C57Bl/6j mice is discussed.

Effects of bulbectomy and subsequent antidepressant treatment on brain 5-HT2 and 5-HT1A receptors in mice

The effects of bilateral olfactory bulbectomy on serotonergic 5-HT2 and 5-HT1A receptor binding were studied in the frontal cortex (FC), limbic structures (LS), including the hippocampus, amygdala, olfactory tubercule, and piriform cortex, and hypothalamus (HTH) in mice. Bulbectomy resulted in the increase of Bmax for [3H]spiperone binding with 5-HT2 receptors in FC in C57Bl/6j. The receptors in LS and HTH remained unchanged. Subchronic treatment of the bulbectomized mice with antidepressant trazodone (20 mg/kg/day, IP, 14 days) induced downregulation of 5-HT2 receptors in FC and LS. The other two antidepressants used, amitriptyline (20 mg/kg/day, IP, 14 days) and imipramine (10 mg/kg/day, IP, 14 days), did not alter these receptors. [3H]8-OH-DPAT binding with 5-HT1A receptors was not altered by bulbectomy in any brain area in C57Bl/6j mice. Amitriptyline and trazodone decreased Bmax for these receptors in FC in the bulbectomized mice while imipramine was ineffective. Amitriptyline and imipramine significantly increased Bmax and decreased Kd in HTH, and trazodone displayed the same tendency. Bulbectomy did not alter 5-HT2 receptors in DBA/2j mice. Amitriptyline increased Kd in the all brain areas without changing Bmax in the bulbectomized DBA/2j mice. Trazodone significantly decreased Bmax in FC and increased Kd in FC and LS. Imipramine decreased Bmax while increasing Kd in LS. The possible involvement of the serotonin receptor subtypes in the bulbectomy-induced behavioral deficits and in the restorative action of the antidepressants is discussed.

Dissociation of multiple behavioral effects between olfactory bulbectomized C57Bl/6J and DBA/2J mice

The behavioral effects of bulbectomy and subsequent antidepressant treatment in two mice strains were compared on measures of open field behavior and passive and active avoidance 2 and 4 weeks after surgery. After bulbectomy, both strains displayed elevated locomotion in open field, corrected by antidepressants. Enhanced rearing was decreased by antidepressants in C57Bl/6J, but not in DBA/2J mice. Passive avoidance, being intact 2 weeks after surgery in both strains, was strongly impaired 4 weeks after bulbectomy in C57Bl/6J mice, with antidepressants restoring the performance. Active avoidance acquisition and retention were also dramatically disturbed in C57Bl/6J mice 2 and 4 weeks after surgery, and antidepressants had recuperative effect. In contrast, bulbectomized DBA/2J mice didn't show any significant passive or active avoidance deficits, and antidepressant treatment seemed to have no effect on their learning ability. The observed strain differences suggest that bulbectomy may produce quite diverse neurophysiological and neurochemical alterations in two strains.

[The behavioral and biochemical sequelae of the removal of the olfactory bulbs in C57Bl/6j mice]

Ablation of the olfactory bulbs in mice C57Bl/6j was accompanied by motor and orienting-exploratory activity augmentation in the "open field" test and deterioration of the learning ability to active and passive avoidance. The most expressed behavioural changes developed in four weeks after the surgery. Chronic administration of antidepressants (amitriptyline, 20 mg/kg; trazodone, 20 mg/kg; imipramine, 10 mg/kg; intraperitoneally) normalized behaviour of bulbectomized animals, trazodone being the most effective. In the biochemical studies the brainstem serotonin level was found to be decreased and the density of 5HT2-receptors in the cerebral cortex increased in bulbectomized mice. Only trazodone was able to correct the biochemical indices. The state of the bulbectomized mice is supposed to serve a model of a depression with hypo-function of serotonergic system of the brain.

Influence of local injection of 5,7-DHT and 6-OH-DA into the neocortex on learning and exploratory behavior of rats in the open field

The features of the exploratory behavior in the open field, of the learning of a conditioned-reflex food-procuring reaction, and of the shift in the level of biogenic amines of the brain was studied in Wistar rats with local injections of the specific neurotoxins 6-hydroxydopamine (6-OH-DA) and 5,7-dihydroxytryptamine (5,7-DHT). It was shown that damage to the structure of the serotoninergic or catecholaminergic systems of the frontal cortex and hippocampus caused by local injection of 6-OH-DA and 5,7-DHT into the neocortex is accompanied by multidirectional changes in the exploratory behavior and learning of the animals.