scholarly journals Tryptophan-Tyrosine Dipeptide, the Core Sequence of β-Lactolin, Improves Memory by Modulating the Dopamine System

Nutrients ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 348 ◽  
Author(s):  
Yasuhisa Ano ◽  
Tatsuhiro Ayabe ◽  
Rena Ohya ◽  
Keiji Kondo ◽  
Shiho Kitaoka ◽  
...  

Tryptophan-tyrosine (WY)-related peptides including the β-lactopeptide of the glycine-threonine-tryptophan-tyrosine peptide, β-lactolin, improve spatial memory. However, whether and how the WY dipeptide as the core sequence in WY-related peptides improves memory functions has not been investigated. This study assessed the pharmacological effects of the WY dipeptide on memory impairment to elucidate the mechanisms. Here, we showed that oral administration of dipeptides of WY, tryptophan-methionine (WM), tryptophan-valine, tryptophan-leucine, and tryptophan-phenylalanine improved spontaneous alternation of the Y-maze test in scopolamine-induced amnesic mice. In contrast, tyrosine-tryptophan, methionine-tryptophan, tryptophan, tyrosine, and methionine had no effect. These results indicated that the conformation of dipeptides with N-terminal tryptophan is required for their memory improving effects. WY dipeptide inhibited the monoamine oxidase B activity in vitro and increased dopamine levels in the hippocampus and frontal cortex, whereas tryptophan did not cause these effects. In addition, the treatment with SCH-23390, a dopamine D1-like receptor antagonist, and the knockdown of the hippocampal dopamine D1 receptor partially attenuated the memory improvement induced by the WY dipeptide. Importantly, WY dipeptide improved the spontaneous alternations of the Y-maze test in aged mice. These results suggest that the WY dipeptide restores memory impairments by augmenting dopaminergic activity. The development of supplements rich in these peptides might help to prevent age-related cognitive decline.

1988 ◽  
Vol 8 (7) ◽  
pp. 2690-2697
Author(s):  
P Friden ◽  
P Schimmel

LEU3 of Saccharomyces cerevisiae encodes an 886-amino-acid polypeptide that regulates transcription of a group of genes involved in leucine biosynthesis and has been shown to bind specifically to a 114-base-pair DNA fragment of the LEU2 upstream region (P. Friden and P. Schimmel, Mol. Cell. Biol. 7:2707-2717, 1987). We show here that, in addition to LEU2, LEU3 binds in vitro to sequences in the promoter regions of LEU1, LEU4, ILV2, and, by inference, ILV5. The largely conserved decanucleotide core sequence shared by the binding sites in these genes is CCGGNNCCGG. Methylation interference footprinting experiments show that LEU3 makes symmetrical contacts with the conserved bases that lie in the major groove. Synthetic oligonucleotides (19 to 29 base pairs) which contain the core decanucleotide and flanking sequences of LEU1, LEU2, LEU4, and ILV2 have individually been placed upstream of a LEU3-insensitive test promoter. The expression of each construction is activated by LEU3, although the degree of activation varies considerably according to the specific oligonucleotide which is introduced. A promoter construction with substitutions in the core sequence remains LEU3 insensitive, however. One of the oligonucleotides (based on a LEU2 sequence) was also tested and shown to confer leucine-sensitive expression on the test promoter. The results demonstrate that only a short sequence element is necessary for LEU3-dependent promoter binding and activation and provide direct evidence for an expanded repertoire of genes that are activated by LEU3.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chang-Yul Kim ◽  
Yongtaek Seo ◽  
Chan Lee ◽  
Gyu Hwan Park ◽  
Jung-Hee Jang

We have investigated the neuroprotective and memory enhancing effect of [6]-gingerol (GIN), a pungent ingredient of ginger, using an animal model of amnesia. To determine the neuroprotective effect of GIN on cognitive dysfunction, scopolamine (SCO, 1 mg/kg, i.p.) was injected into C57BL/6 mice, and a series of behavioral tests were conducted. SCO-induced behavior changes and memory impairments, such as decreased alteration (%) in Y-maze test, increased mean escape latency in water maze test, diminished step-through latency in passive avoidance test, and shortened freezing time in fear condition test, were significantly prevented and restored by the oral administration of GIN (10 or 25 mg/kg/day). To further verify the neuroprotective mechanism of GIN, we have focused on the brain-derived neurotrophic factor (BDNF). The administration of GIN elevated the protein expression of BDNF, which was mediated via the activation of protein kinase B/Akt- and cAMP-response element binding protein (CREB) signaling pathway. These results suggest that GIN may have preventive and/or therapeutic potentials in the management of memory deficit and cognitive impairment in mice with amnesia.


1998 ◽  
Vol 363 (2-3) ◽  
pp. 211-215 ◽  
Author(s):  
Nelson E Lezcano ◽  
Nancy A Salvatierra ◽  
Maria Ester Celis

Author(s):  
Mahboubeh Bozorgi ◽  
◽  
Zahra Najafi ◽  
Sahar Omidpanah ◽  
Arash Sadri ◽  
...  

Alzheimer’s disease (AD) is an age-related neurodegenerative disorder. Sever cognitive and memory impairments, huge increase in the prevalence of the disease, and lacking definite cure have absorbed worldwide efforts to develop therapeutic approaches. Since many drugs have failed in the clinical trials due to multifactorial nature of AD, symptomatic treatments are still in the center attention and now, nootropic medicinal plants have been found as versatile ameliorators to reverse memory disorders. In this work, anti-Alzheimer’s activity of aqueous extract of areca nuts (Areca catechu L.) was investigated via in vitro and in vivo studies. It depicted good amyloid β (Aβ) aggregation inhibitory activity, 82% at 100 µg/mL. In addition, it inhibited beta-secretase 1 (BACE1) with IC50 value of 19.03 µg/mL. Evaluation of neuroprotectivity of the aqueous extract of the plant against H2O2-induced cell death in PC12 neurons revealed 84.5% protection at 1 µg/mL. It should be noted that according to our results obtained from Morris Water Maze (MWM) test, the extract reversed scopolamine-induced memory deficit in rats at concentrations of 1.5 and 3 mg/kg.


2020 ◽  
Vol 61 (10) ◽  
pp. 1308-1319
Author(s):  
Eileen E. Parks ◽  
Sreemathi Logan ◽  
Alexander Yeganeh ◽  
Julie A. Farley ◽  
Daniel B. Owen ◽  
...  

Cognitive decline with age is a harmful process that can reduce quality of life. Multiple factors have been established to contribute to cognitive decline, but the overall etiology remains unknown. Here, we hypothesized that cognitive dysfunction is mediated, in part, by increased levels of inflammatory cytokines that alter allopregnanolone (AlloP) levels, an important neurosteroid in the brain. We assessed the levels and regulation of AlloP and the effects of AlloP supplementation on cognitive function in 4-month-old and 24-month-old male C57BL/6 mice. With age, the expression of enzymes involved in the AlloP synthetic pathway was decreased and corticosterone (CORT) synthesis increased. Supplementation of AlloP improved cognitive function. Interestingly, interleukin 6 (IL-6) infusion in young animals significantly reduced the production of AlloP compared with controls. It is notable that inhibition of IL-6 with its natural inhibitor, soluble membrane glycoprotein 130, significantly improved spatial memory in aged mice. These findings were supported by in vitro experiments in primary murine astrocyte cultures, indicating that IL-6 decreases production of AlloP and increases CORT levels. Our results indicate that age-related increases in IL-6 levels reduce progesterone substrate availability, resulting in a decline in AlloP levels and an increase in CORT. Furthermore, our results indicate that AlloP is a critical link between inflammatory cytokines and the age-related decline in cognitive function.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Di Hu ◽  
Yunfeng Cao ◽  
Rongrong He ◽  
Na Han ◽  
Zhihui Liu ◽  
...  

In the present study, we examined the effect of schisandrin (SCH) ofSchisandra chinensison the amyloid-beta1–42- (Aβ1–42-) induced memory impairment in mice and elucidated the possible antioxidative mechanism. Mice were intracerebroventricular (i.c.v.) injected with the aggregated Aβ1–42and then treated with SCH (4, 12, and 36 mg/kg body weight) or donepezil (DPZ), a reference drug (0.65 mg/kg) by intragastric infusion for 14 days. Noncognitive disturbances and cognitive performance were evaluated by locomotor activity test, Y-maze test, and water maze test. Antioxidative enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GSH-px) and levels of malondialdehyde (MDA), glutathione (GSH), and oxidized glutathione (GSSG) within the cerebral cortex and hippocampus of mice were measured to elucidate the mechanism. Our results showed that SCH significantly improved Aβ1–42-induced short-term and spatial reference memory impairments in Y-maze test and water maze test. Furthermore, in the cerebral cortex and hippocampus of mice, SOD and GSH-px activities, GSH level, and GSH/GSSG ratio were increased, and levels of MDA and GSSG were decreased by the treatment of SCH. These results suggest that SCH is a potential cognitive enhancer against Alzheimer’s disease through antioxidative action.


1988 ◽  
Vol 8 (7) ◽  
pp. 2690-2697 ◽  
Author(s):  
P Friden ◽  
P Schimmel

LEU3 of Saccharomyces cerevisiae encodes an 886-amino-acid polypeptide that regulates transcription of a group of genes involved in leucine biosynthesis and has been shown to bind specifically to a 114-base-pair DNA fragment of the LEU2 upstream region (P. Friden and P. Schimmel, Mol. Cell. Biol. 7:2707-2717, 1987). We show here that, in addition to LEU2, LEU3 binds in vitro to sequences in the promoter regions of LEU1, LEU4, ILV2, and, by inference, ILV5. The largely conserved decanucleotide core sequence shared by the binding sites in these genes is CCGGNNCCGG. Methylation interference footprinting experiments show that LEU3 makes symmetrical contacts with the conserved bases that lie in the major groove. Synthetic oligonucleotides (19 to 29 base pairs) which contain the core decanucleotide and flanking sequences of LEU1, LEU2, LEU4, and ILV2 have individually been placed upstream of a LEU3-insensitive test promoter. The expression of each construction is activated by LEU3, although the degree of activation varies considerably according to the specific oligonucleotide which is introduced. A promoter construction with substitutions in the core sequence remains LEU3 insensitive, however. One of the oligonucleotides (based on a LEU2 sequence) was also tested and shown to confer leucine-sensitive expression on the test promoter. The results demonstrate that only a short sequence element is necessary for LEU3-dependent promoter binding and activation and provide direct evidence for an expanded repertoire of genes that are activated by LEU3.


2000 ◽  
Vol 17 (6) ◽  
pp. 839-845 ◽  
Author(s):  
M.W. HANKINS

The activity of the endogenous retinal dopamine (DA) pathway has been examined in the pigmented rat using retinas obtained from normal adult (∼3 months) and senile adults (∼24 months) using an in vitro electrophysiological approach. By comparing the pharmacological sensitivity of the horizontal cells (HCs) to exogenous DA, a D1 receptor antagonist (SCH 23390) and a DA-transport inhibitor (nomifensine), it is suggested that there is a functional deficit in the endogenous DA activity in the senile retina. Cells recorded from retinae obtained from senile animals are more sensitive to exogenous DA, whilst the senile retina is insensitive to SCH 23390. In addition, nomifensine was effective in potentiating subthreshold DA applications, but only in the normal adult retina. The data may suggest that endogenous DA release upon the HCs and selective re-uptake are suppressed in these retinae. These functional deficits also appear to be associated with changes in the receptive fields of the HCs, suggesting there is a corresponding deficit in spatial processing at the outer plexiform layer (OPL) of the senile rat.


2021 ◽  
Vol 13 ◽  
Author(s):  
Ryosuke Tsumagari ◽  
Kenta Maruo ◽  
Takaaki Nakao ◽  
Shuji Ueda ◽  
Minoru Yamanoue ◽  
...  

Senescence-accelerated mouse prone 8 (SAMP8) is an animal model of age-related central nervous system (CNS) disorders. Although SAMP8 shows deficits in learning, memory, and emotion, its motor coordination has not been clarified. We have recently reported that DGKγ-regulated PKCγ activity is important for cerebellar motor coordination. However, involvement of the functional correlation between the kinases in age-related motor dyscoordination still remains unknown. Therefore, we have investigated the motor coordination in SAMP8 and involvement of the functional correlation between DGKγ and PKCγ in the age-related motor dyscoordination. Although 6 weeks old SAMP8 showed equivalent motor coordination with control mice (SAMR1) in the rotarod test, 24 weeks old SAMP8 exhibited significantly less latency in the rotarod test and more frequent slips in the beam test compared to the age-matched SAMR1. Furthermore, 24 weeks old SAMP8 showed the higher locomotor activity in open field test and Y-maze test. Western blotting revealed that DGKγ expression decreased in the cerebellum of 24 weeks old SAMP8, while PKCγ was upregulated. These results suggest that SAMP8 is a useful model of age-related motor dysfunction and that the DGKγ-regulated PKCγ activity is involved in the age-related motor dyscoordination.


Author(s):  
Yvonne Rogalski ◽  
Muriel Quintana

The population of older adults is rapidly increasing, as is the number and type of products and interventions proposed to prevent or reduce the risk of age-related cognitive decline. Advocacy and prevention are part of the American Speech-Language-Hearing Association’s (ASHA’s) scope of practice documents, and speech-language pathologists must have basic awareness of the evidence contributing to healthy cognitive aging. In this article, we provide a brief overview outlining the evidence on activity engagement and its effects on cognition in older adults. We explore the current evidence around the activities of eating and drinking with a discussion on the potential benefits of omega-3 fatty acids, polyphenols, alcohol, and coffee. We investigate the evidence on the hypothesized neuroprotective effects of social activity, the evidence on computerized cognitive training, and the emerging behavioral and neuroimaging evidence on physical activity. We conclude that actively aging using a combination of several strategies may be our best line of defense against cognitive decline.


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