Colostrinin, a polypeptide isolated from early milk, facilitates learning and memory in rats

Proline-rich polypeptides (Colostrinin®/COLOCO®) modulate BDNF concentration in blood affecting cognitive function in adults: A double-blind randomized placebo-controlled study

Proline-rich polypeptides (PRPs complex also known as COLOCO^®, Colostrinin^®) consist of low-molecular weight peptides ranging up to 10 kDa, isolated from the bovine colostrum obtained up to 48 h postpartum. PRPs have been shown to affect processes involved in inflammation, brain aging, and neurodegeneration. The aim of this study was to investigate the effect of Colostrinin^® (COLOCO^®) on the cognitive abilities of healthy volunteers in three different age groups using the CANTAB tool in a double-blind randomized placebo-controlled study. BDNF serum level was used as a physicochemical marker of improvement of the cognitive skills. Three hundred and sixty-one healthy volunteers were divided into three study groups aged 18-24, 25-54, and 55-75; each group was then divided into two subgroups which took either placebo or tested lozenge with 120 μg of PRPs for the period of 4 months. The CANTAB battery test was used to measure the efficacy of PRP in the context of cognitive functioning. After the treatment with COLOCO^®, we observed differences within MoCA score in the oldest patients, improvement in DMS and drop in PAL scores within the youngest group, drop in RTI and improvement in RVP scores within the middle-aged group. It was observed that serum BDNF level increased in all study groups which confirms cognitive improvement. In conclusion, we have shown that Colostrinin^® exhibits cognitive enhancing effects, probably through the modulation of BDNF concentrations.

Breast Milk: A Source of Functional Compounds with Potential Application in Nutrition and Therapy

Breast milk is an unbeatable food that covers all the nutritional requirements of an infant in its different stages of growth up to six months after birth. In addition, breastfeeding benefits both maternal and child health. Increasing knowledge has been acquired regarding the composition of breast milk. Epidemiological studies and epigenetics allow us to understand the possible lifelong effects of breastfeeding. In this review we have compiled some of the components with clear functional activity that are present in human milk and the processes through which they promote infant development and maturation as well as modulate immunity. Milk fat globule membrane, proteins, oligosaccharides, growth factors, milk exosomes, or microorganisms are functional components to use in infant formulas, any other food products, nutritional supplements, nutraceuticals, or even for the development of new clinical therapies. The clinical evaluation of these compounds and their commercial exploitation are limited by the difficulty of isolating and producing them on an adequate scale. In this work we focus on the compounds produced using milk components from other species such as bovine, transgenic cattle capable of expressing components of human breast milk or microbial culture engineering.

Food-Derived Opioid Peptides in Human Health: A Review

World Health Organization data suggest that stress, depression, and anxiety have a noticeable prevalence and are becoming some of the most common causes of disability in the Western world. Stress-related disorders are considered to be a challenge for the healthcare system with their great economic and social impact. The knowledge on these conditions is not very clear among many people, as a high proportion of patients do not respond to the currently available medications for targeting the monoaminergic system. In addition, the use of clinical drugs is also associated with various side effects such as vomiting, dizziness, sedation, nausea, constipation, and many more, which prevents their effective use. Therefore, opioid peptides derived from food sources are becoming one of the safe and natural alternatives because of their production from natural sources such as animals and plant proteins. The requirement for screening and considering dietary proteins as a source of bioactive peptides is highlighted to understand their potential roles in stress-related disorders as a part of a diet or as a drug complementing therapeutic prescription. In this review, we discussed current knowledge on opioid endogenous and exogenous peptides concentrating on their production, purification, and related studies. To fully understand their potential in stress-related conditions, either as a drug or as a therapeutic part of a diet prescription, the need to screen more dietary proteins as a source of novel opioid peptides is emphasized.

Beneficial effect of ovocystatin on the cognitive decline in APP/PS1 transgenic mice

PURPOSE

Cystatin C plays an important role in the course of neurodegenerative diseases and has a beneficial effect through inhibiting cysteine proteases and amyloid-β aggregation. It also induces proliferation and autophagy. Cystatin isolated from chicken egg white, called ovocystatin, has been widely used in the medical and pharmaceutical research due to its structural and biological similarities to human cystatin C. The aim of this study was to assess the effect of administering ovocystatin on the development of dementia-specific cognitive deficits in APP/PS1 transgenic mice.

MATERIALS/METHODS

The study was conducted on transgenic B6C3-Tg(APPswe,PSEN1dE9)85Dbo/Mmjax mice. Ovocystatin was administered to four-month-old transgenic (AD) and wild type (NCAR) mice in drinking water for 24 weeks (at a dose of 40 and 4 μg/ mouse). The locomotor activity and cognitive functions were determined using an actimeter and the Morris water maze test, respectively.

RESULTS

The results of the study indicate that ovocystatin has a beneficial effect on the cognitive functions in APP/PS1 transgenic mice. The strongest effects of ovocystatin were found in the group of AD mice, where ovocystatin was administered in drinking water at a dose of 40 μg/mouse (p < 0.05). Mice from the AD group swam statistically significantly further in the target zone during the trial in the Morris water maze compared to the AD (vehiculum) group (p < 0.05).

CONCLUSIONS

The obtained results encourage further research into the protective effect, which may be used as an adjuvant in the treatment of deteriorating cognitive functions.

Nucleic Acid-Based Theranostics for Tackling Alzheimer's Disease

Nucleic acid-based technologies have received significant interest in recent years as novel theranostic strategies for various diseases. The approval by the United States Food and Drug Administration (FDA) of Nusinersen, an antisense oligonucleotide drug, for the treatment of spinal muscular dystrophy highlights the potential of nucleic acids to treat neurological diseases, including Alzheimer's disease (AD). AD is a devastating neurodegenerative disease characterized by progressive impairment of cognitive function and behavior. It is the most common form of dementia; it affects more than 20% of people over 65 years of age and leads to death 7-15 years after diagnosis. Intervention with novel agents addressing the underlying molecular causes is critical. Here we provide a comprehensive review on recent developments in nucleic acid-based theranostic strategies to diagnose and treat AD.

Pro-Cognitive Properties of the Immunomodulatory Polypeptide Complex, Yolkin, from Chicken Egg Yolk and Colostrum-Derived Substances: Analyses Based on Animal Model of Age-Related Cognitive Deficits

The study aimed to assess the effect of the polypeptide Y complex (Yolkin), isolated from chicken egg yolk, on behavioural and cognitive functions. It also aimed to compare this activity with colostrum-derived substances (Colostrinin, Coloco), which have a confirmed impact on learning and memory. In the study, the effect of Yolkin, administered to rats of different ages, who performed various tasks involving spatial and episodic memory, motor functions and exploratory behavior, was assessed. The experiment was carried out in rats which were 6 and 12 months old. Two different doses of the studied specimens based on previous comparative studies and two different routes of administration (oral and retroperitoneal) were used. A series of behavioural tests were carried out, including an open field test, a novel object recognition test and a Morris water maze. They were used to evaluate the impact of the studied specimen on improving locomotor function and exploratory behaviour, preventing their decline and assess the functioning of episodic and spatial memory in aging rats. The administration of Yolkin gave distinct effects compared to colostrum-derived substances, although confirmed its suggested pro-cognitive action. Therefore, it may be used to enhance cognitive functions and inhibit the progression of dementia in the course of neurodegenerative disorders.

Clinical applications of bioactive milk components

Milk represents a unique resource for translational medicine: It contains a rich pool of biologically active molecules with demonstrated clinical benefits. The ongoing characterization of the mechanistic process through which milk components promote development and immunity has revealed numerous milk-derived compounds with potential applications as clinical therapies in infectious and inflammatory disease, cancer, and other conditions. Lactoferrin is an effective antimicrobial and antiviral agent in high-risk patient populations and a potentially potent adjuvant to chemotherapy in lung cancer. Enteric nutrition formulas supplemented with transforming growth factor β, a milk cytokine, have been shown to promote remission in pediatric Crohn's disease. A number of milk glycans, including human milk oligosaccharides, show promise in preclinical studies as antimicrobial and anti-inflammatory agents. While active preclinical investigations of human milk may soon result in large-scale production of human milk molecules, bovine milk components in many instances represent a practical source of bioactive milk compounds for use in clinical trials. This review summarizes current efforts to translate the compounds derived from human and bovine milk into effective clinical therapies. These efforts suggest a common pathway for the translation of milk-derived compounds into clinical applications.

Effect of the proline-rich polypeptide complex/colostrinin™ on the enzymatic antioxidant system

Proline-rich polypeptide complex (PRP) and its constituent nonapeptide (NP) possess immunoregulatory and procognitive properties. PRP in the form of sublingually administered tablets called Colostrinin™ improves the outcome of patients with Alzheimer's disease (AD). Free radical-induced oxidative stress has been implicated in the pathogenesis of AD. It has been previously shown that PRP and NP inhibit overproduction of reactive oxygen species, nitric oxide and proinflammatory cytokines induced by lipopolysaccharide or PMA. Antioxidant defense includes both low molecular weight components and enzymatic systems including dismutases, catalase, glutathione reductase (GSSGR) and glutathione peroxidase (GSHPx). An early event during the development of AD is lipid and protein peroxidation. PRP and NP showed no modulatory effect on lipid peroxidation. A protective effect on protein oxidation was found only when high doses of NP were used. We have previously shown, in a model of human peripheral blood mononuclear cells, that PRP/NP affects activities of superoxide dismutase and NF-κB. In the present study with the use of the same cell model and whole blood cells we observed an activatory effect of PRP/NP on GSHPx and GSSGR activity but not catalase. The observed effect suggests that PRP/NP can act as a modulatory agent of the "first line" of antioxidant defense. It can be assumed therefore that PRP/Colostrinin by regulation of the early phase of the redox system does not reduce but rather prevents oxidative damage. This effect may shed some light on the beneficial effect of PRP/Colostrinin in AD patients.

Dairy constituents and neurocognitive health in ageing

Age-related cognitive decline (ARCD) and dementia are of increasing concern to an ageing population. In recent years, there has been considerable research focused on effective dietary interventions that may prevent or ameliorate ARCD and dementia. While a number of studies have considered the impact that dairy products may have on physiological health, particularly with regard to the metabolic syndrome and cardiovascular health, further research is currently needed in order to establish the impact that dairy products have in the promotion of healthy brain function during ageing. The present review considers the available evidence for the positive effects of dairy products on the metabolic syndrome and glucose regulation, with consideration of the implications for neurocognitive health. A literature search of current (September 2010) meta-analyses/reviews and original research regarding dairy products and cognition was conducted through SCOPUS using the following search terms for dairy consituents: dairy, milk, cheese, yoghurt, probiotics, whey protein, alpha lactalbumin, calcium, B-12, bioactive peptides and colostrinin (CLN). These search terms for dairy products were combined with the following search terms related to cognition and health: cognition, cognitive decline, dementia, Alzheimer's disease, metabolic syndrome, diabetes, insulin resistance and glucose regulation. Concerns regarding SFA and other fatty acids found in dairy products are also reviewed in relation to different forms of dairy products. The review also considers recent evidence for positive neurocognitive effects associated with bioactive peptides, CLN and proline-rich polypeptides, α-lactalbumin, vitamin B12, calcium and probiotics. Future directions for the extraction and purification of beneficial constituents are also discussed. It is concluded that low-fat dairy products, when consumed regularly as part of a balanced diet, may have a number of beneficial outcomes for neurocognitive health during ageing.

Intensification of maternal care by double-mothering boosts cognitive function and hippocampal morphology in the adult offspring

Mice born from high care-giving females show, as adults, low anxiety levels, decreased responsiveness to stress, and substantial improvements in cognitive function and hippocampal plasticity. Given the relevance of this issue for preventing emotional and cognitive abnormalities in high-risk subjects, this study examines the possibility to further enhance the beneficial effects observed in the progeny by augmenting maternal care beyond the highest levels females can display in standard laboratory conditions. This was produced by placing a second female with the dam and its litter in the rearing cage from the partum until pups weaning. Maternal behavior of all females was scored during the first week postpartum, and behavioral indices of emotionality, prestress and poststress corticosterone levels, cognitive performance, and hippocampal morphology were assessed in the adult offspring. We found that pups reared by female dyads received more maternal care than pups reared by dams alone, but as adults, they did not exhibit alterations in emotionality or corticosterone response estimated in basal condition or following restraint stress. Conversely, they showed enhanced performance in hippocampal-dependent tasks including long-term object discrimination, reactivity to spatial change, and fear conditioning together with an increase in dendritic length and spine density in the CA1 region of the hippocampus. In general, the beneficial effects of dyadic maternal care were stronger when both the females were lactating. This study demonstrates that double-mothering exerts a long-term positive control on cognitive function and hippocampal neuronal connectivity. This experimental manipulation, especially if associated with increased feeding, might offer a concrete possibility to limit or reverse the consequences of negative predisposing conditions for normal cognitive development.

Natural products as a source of Alzheimer's drug leads

This review focuses on recent developments in the use of natural products as therapeutics for Alzheimer's disease. The compounds span a diverse array of structural classes and are organized according to their mechanism of action, with the focus primarily on the major hypotheses. Overall, the review discusses more than 180 compounds and summarizes 400 references.

The protective effects of the nutraceutical, colostrinin, against Alzheimer's disease, is mediated via prevention of apoptosis in human neurones induced by aggregated beta-amyloid

OBJECTIVE

It has previously been demonstrated that oral administration of ovine Colostrinin (CLN), a proline-rich polypeptide isolated from ovine colostrum, can effectively treat Alzheimer's disease patients. This study aims to determine whether CLN has effects on the aggregation and toxicity of synthetic beta-amyloid (Abeta), implicated as a causative agent of AD.

DESIGN AND MEASUREMENTS

Using cell assays, we examined if pre-treatment of neuronal cells with CLN confers protection.

RESULTS

The data from cytotoxicity assays (using MTT and LDH) demonstrated that pre-treatment of human neuronal SHSY-5Y cells with 5 microg/ml CLN, for 24 hours, confers neuroprotection against Abeta-induced neurotoxicity. Twenty-four hour pre-treatment with 5 microg/ml CLN was also shown to reduce Abeta 1-40-induced apoptosis in human neuronal cells as determined via qualitative and quantitative apoptosis assays.

CONCLUSION

The neuroprotection conferred with CLN pre-treatment was reduced with the Fas ligand (FasL) binding antibody Nok1, suggesting that the effects of CLN may involve a Fas:soluble FasL interaction. These findings indicate that CLN could possibly play a role in the prevention of AD pathogenesis, though the inhibition of Fas-mediated apoptosis.

Colostrinin: a naturally occurring compound derived from mammalian colostrum with efficacy in treatment of neurodegenerative diseases, including Alzheimer's

Neurodegenerative illnesses such as Alzheimer's disease and their debilitating effects pose a major problem as their incidence increases. Although clinical management of neurodegenerative diseases usually involves symptomatic treatment, Colostrinin() (CLN), which has efficacy in counteracting neural degradation and in stimulating neural growth, might prove to be a more effective means to deal with the causes of Alzheimer's and other neurodegenerative diseases. Evidence for the clinical efficacy of CLN is discussed and recent data examined showing the remarkable ability of CLN to reduce oxidative stress, prevent beta-amyloid aggregation and prolong the lifespan in a laboratory model of premature ageing. An increasingly important application for CLN has been as a nutraceutical product for use in the early stages of cognitive decline in humans, with licensed use in North America and Australia, and now in Europe. It might also be of considerable utility as a veterinary nutraceutical for companion animals.

Ovine colostrum nanopeptide affects amyloid beta aggregation

A colostral proline-rich polypeptide complex (PRP) consisting of over 30 peptides shows beneficial effects in Alzheimer's disease (AD) patients when administered in the form of sublinqual tablets called Colostrinin. The aim of the present studies was to investigate whether nanopeptide fragment of PRP (NP) - one of the PRP complex components can affect aggregation of amyloid beta (Abeta1-42). The effect of NP on Abeta aggregation was studied using Thioflavin T (ThT) binding, atomic force microscopy, and analyzing circular dichroism spectra. Results presented suggest that NP can directly interact with amyloid beta, inhibit its aggregation and disrupt existing aggregates acting as a beta sheet breaker and reduce toxicity induced by aggregated forms of Abeta.

A proline-rich polypeptide from ovine colostrum: colostrinin with immunomodulatory activity

A proline-rich polypeptide (PRP), later called colostrinin (CLN), was originally found as a fraction accompanying sheep colostral immunoglobulins. Extensive in vitro and in vivo studies in mice revealed its interesting T cell-tropic activities. The polypeptide promoted T cell maturation from early thymic precursors that acquired the phenotype and function of mature, helper cells; on the other hand, it also affected the phenotype and function of mature T cells. In particular, PRP was shown to recruit suppressor T cells in a model of T cell-independent humoral immune response and suppressed autoimmune hemolytic anemia in New Zealand Black mice. Subsequent in vitro studies in the human model revealed that CLN regulated mitogen-induced cytokine production in whole blood cultures. A discovery that CLN promoted procognitive functions in experimental animal models, supported by other laboratory findings, indicating prevention of pathological processes in the central nervous system, led to application of CLN in multicenter clinical trials. The trials demonstrated the therapeutic benefit of CLN in Alzheimer's disease (AD) patients by delaying progress of the disease.

Proline-rich polypeptides in Alzheimer's disease and neurodegenerative disorders -- therapeutic potential or a mirage?

The development of effective and safe drugs for a growing Alzheimer disease population is an increasing need at present. Both experimental and clinical evidence support a beneficial effect of proline-rich polypeptides in a number of neurodegenerative diseases, including Alzheimer disease. Experimental data have shown that proline-rich polypeptides isolated from bovine neurohypophisis possess neuroprotective and neuromodulatory properties in mice with aluminum neurotoxicosis or neuronal damage caused by venoms and toxins. Proline-rich polypeptides from ovine colostrums, so called Colostrinin, have been shown to produce cognitive improvement in an experimental model and in patients with Alzheimer disease. However, the precise mechanism underlying the neuroprotective action of proline-rich polypeptides is not very well established. Moreover, studies pointing at a neuroprotective effect of proline-rich polypeptides from bovine neurohypophisis in humans have not been reported thus far. The authors conclude that more detailed information on the mode of action of proline-rich polypeptides is needed as well as confirmation of their efficacy in broad clinical trials before this approach can really show its potential in the treatment of neurodegenerative disorders.

A proline-rich polypeptide complex (PRP) isolated from ovine colostrum. Modulation of H2O2 and cytokine induction in human leukocytes

A proline-rich polypeptide complex (PRP) has immunoregulatory properties and also shows beneficial effects in Alzheimer's disease (AD). It is known that the unregulated activation of microglial cells in AD may result in chronic inflammatory response. There is a link between the activation of immune cells on the periphery and in the central nervous system (CNS). Therefore, we studied the effect of the PRP on human peripheral blood mononuclear cells (PBMCs) stimulated by LPS with PHA (LP) or PMA as proinflammatory activators. PRP and its nonapeptide fragment (NP) inhibited by 40-60% production of H(2)O(2) induced by PMA. The peptides also inhibited activity of superoxide dismutase. Both peptide preparations showed differential effects on the secretion of cytokines. NP induced TNF-alpha only while PRP induced IL-6, IL-10 and TNF-alpha. On the other hand, the release of TNF-alpha and IL-10 induced by LP in PBMCs was inhibited by PRP while NP inhibited the release of IFN-gamma and IL-10. The results obtained showed that PRP may affect not only adaptive immunity but also innate immunity and thus may regulate secretions of mediators of inflammation. The regulatory effect of the PRP on the innate immunity may shed some light on understanding the beneficial effects of this polypeptide complex in AD patients.

Enhancement of long-term memory retention by Colostrinin in one-day-old chicks trained on a weak passive avoidance learning paradigm

Colostrinin (CLN) is a biologically active proline-rich polypeptide which has therapeutic potential for the alleviation of memory deficits in age-related dementias in a number of human conditions, particularly Alzheimer's disease. To examine the efficacy of CLN in other species, day-old domestic chicks were used as a model system to study its effects on retention of memory for a single one-trial learning paradigm--avoidance of a bitter-tasting substance (methylanthranilate, MeA). Birds were presented with a bead coated with either a dilute (10%) solution of MeA or a bead coated with 100% MeA. Those trained on 100% MeA avoided pecking at a similar but dry bead 24 h later, thereby demonstrating long-term memory whereas chicks trained on the 10% solution pecked the bead at 24 h, indicating lack of long term memory for the task. However, when CLN was injected (i.c.) into a region known to be important in memory formation, the mesopallium intermediomediale (IMM), prior to training with 10% MeA, chicks exhibited strong memory retention at 24 h, similar to those trained on 100% MeA. Control chicks trained on 10% MeA but injected i.c. with a 10% saline solution did not show improvement in memory retention. Intraperitoneal (i.p.) injections of CLN were as effective as the i.c. route. These data extend the known efficacy of CLN from mammals demonstrating its widespread efficacy as a cognitive enhancer.

Studies on the mechanism of action of a proline-rich polypeptide complex (PRP): effect on the stage of cell differentiation

A proline-rich polypeptide complex (PRP) with immunoregulatory and procognitive activities shows beneficial effects in Alzheimer's disease (AD). The mechanism of action of PRP in AD is not yet clarified. Here, we present results of the effect of PRP on Vitamin D3-induced phenotypic (CD11b and CD14) and functional (phagocytic) differentiation/maturation of monocytes/macrophages using the premonocytic HL-60 cell line as a model. This cell line can be induced to differentiate into monocyte/macrophage cells by incubation with Vitamin D3. However, when Vitamin D3 was applied together with PRP, a 30-40% inhibition of the expression of the differentiation markers and an over-60% inhibition of phagocytic ability were observed. When PRP was administered to the cells after treatment with Vitamin D3, no attenuation of the differentiation/maturation process of the HL-60 cells was observed. This indicates that PRP affects the early stages of differentiation/maturation of these cells. Our results, therefore, suggest that PRP, which affects the differentiation/maturation processes of cells of monocyte/macrophage lineage, may regulate in this way the inflammatory processes in which these cells participate.

A proline-rich polypeptide complex and its nonapeptide fragment inhibit nitric oxide production induced in mice

A proline-rich polypeptide complex (PRP) isolated from ovine colostrum shows immunoregulatory and procognitive activities. It shows beneficial effects in Alzheimer's disease (AD) patients when orally administered in the form of tablets called Colostrinin. The mechanism of action of PRP/Colostrinin in AD has not been yet clarified. It is known that oxidative stress and overproduction of NO may enhance neurodegenerative processes. PRP regulates the secretion of cytokines, inhibits NO and O2- release in cell cultures. Since the results on isolated cells or cell lines frequently do not reflect the events in vivo, the effect of PRP and its nonapeptide fragment (NP) on the level of NO2- in sera of mice untreated or intraperitoneally treated with LPS was studied. PRP and NP did not induce production of NO. However, when applicated 6 h after LPS, they inhibited the release of NO induced by LPS in about 30-50%. The results in vivo presented in this paper confirm the results obtained in cell cultures and indicate that the beneficial effects of PRP/Colostrinin observed in AD patients may be, among others, due to an inhibition of overproduction of NO.

A proline-rich polypeptide complex (PRP) from ovine colostrum. Studies on the effect of PRP on nitric oxide (NO) production induced by LPS in THP-1 cells

A proline-rich polypeptide complex (PRP) isolated from ovine colostrum shows immunoregulatory activity. Similar activity was observed when PRP was replaced with a nonapeptide (NP) isolated from chymotryptic digest of PRP. The polypeptide complex also shows procognitive activity. In the form of orally administered tablets called Colostrinin, containing 100 microg of PRP, it improves the outcome of Alzheimer's disease (AD) patients. The mechanism of action of PRP/Colostrinin in AD is not yet clarified. Microglial cells involvement in AD has been related to amyloid beta (Abeta) internalization, the release of inflammatory cytokines, overproduction of nitrogen oxide (NO) and superoxide anion (O2-), and the development of neuritic plaques. It has been previously found in our laboratory that PRP regulates the secretion of an array of cytokines. It also was shown, in preliminary experiments using human blood cells and murine macrophages, that PRP inhibits production of NO and O2- induced by LPS. In the present work, to study the effect of PRP and NP on the release of NO and O2-induced by LPS we applied THP-1 cells. The human monocyte/macrophage THP-1 cell line has been widely used as a model of human microglial cells. The results obtained showed that THP-1 cells release NO when activated with LPS. However, neither PRP nor NP induced production of NO. Although the nonapeptide, at higher concentration (100 microg/mL), showed an inhibitory activity on the release of NO induced by LPS, no inhibition was observed when PRP was used. THP-1 cells treated with LPS, PRP or NP did not release O2-.

Effects of a single inhalative exposure to formaldehyde on the open field behavior of mice

The effects of formaldehyde on the explorative behavior and locomotor activity of mice after a single inhalative exposure were examined in an open field. Adult male mice were exposed to approximately 1.1 ppm, 2.3 ppm, or 5.2 ppm formaldehyde vapour for 2 hours and the open field test was carried out two hours after the end of exposure (trial 1) and repeated 24 hours thereafter (trial 2). The following behavioral parameters were quantitatively examined: numbers of crossed floor squares (inner, peripheral, total), sniffing, grooming, rearing, climbing, and incidence of fecal boli. The results of the first trial revealed that the motion activity was significantly reduced in all exposed groups. In the 1.1 ppm group, the frequency of rearing was reduced and that of floor sniffing increased. The exposure to the two higher formaldehyde concentrations caused a significant decrease in total numbers of floor squares crossed by the subjects, air sniffing, and rearing. The open field test on the next day (trial 2) showed that the frequencies of floor sniffing, grooming, and rearing in all formaldehyde groups were significantly altered. In the 2.5 ppm group, an increased incidence of fecal boli was observed. From the results obtained, we conclude that the exposure of male mice to formaldehyde vapour affects their locomotor and explorative activity in the open field, and that some open field parameters are still altered in the exposed animals even after 24 hours.

Cognitive effects of Colostral-Val nonapeptide in aged rats

Colostrinin, a complex of polypeptides derived from sheep colostrum retards the progress of Alzheimer's disease and facilitates acquisition and retrieval of spatial memory in aged rats. Here we investigated the cognitive effects of colostrinin-derived nonapeptide (Colostral-Val nonapeptide, CVNP) in aged rats that demonstrated learning deficits. Administered for 14 days, CVNP did not affect the acquisition of spatial learning or memory retrieval in the Morris water maze. As a result of reversal learning, placebo treated rats shifted searching behavior and swam less in the area of original platform position and more in the area of recent platform position, suggesting formation of the new spatial map. CVNP treated rats did not change the searching pattern and still investigated the area that contained "original" escape platform, suggesting that CVNP treatment delays the extinction of spatial memory. In another experiment, CVNP administered for 8 days did not influence the acquisition of the active avoidance task, but significantly delayed its extinction. The present findings indicate that colostrinin-derived nonapeptide may delay the extinction of long-term memories.