scholarly journals A low repeated dose of Δ9-tetrahydrocannabinol affects memory performance through serotonergic signalling in mice

2021 ◽  
Author(s):  
Lorena Galera-Lopez ◽  
Victoria Salgado-Mendialdua ◽  
Estefania Moreno ◽  
Araceli Bergada-Martinez ◽  
Alex Hoffman ◽  
...  
Keyword(s):  
Memory Impairment ◽  
Low Dose ◽  
Partial Agonist ◽  
Memory Performance ◽  
Long Term Potentiation ◽  
Brain Regions ◽  
High Dose ◽  
Repeated Treatment ◽  
Spine Density ◽  
Cannabinoid Type 1 Receptor

Cannabis is the most widely used illicit drug worldwide. Its principal psychoactive component, ∆9-tetrahydrocannabinol (THC), acts as a partial agonist of the main cannabinoid receptor in the brain, the cannabinoid type-1 receptor (CB1R), being the main responsible for the central effects of THC including memory impairment. CB1Rs may form heterodimers with the serotonin 5-HT2A receptor (5-HT2AR) which were found responsible for the memory impairment produced by acute high dose of THC in mice. In this study we investigated whether a repeated low dose of THC (1 mg/kg), with no acute consequence on memory performance, could eventually have deleterious cognitive effects. We found that such a low dose of THC impairs novel object-recognition memory and fear conditioning memory after repeated treatment (7 days). This deficit was also detected 24 h after the last THC administration. At that time, a general enhancement of c-Fos expression was observed in several brain regions of THC-exposed animals. In addition, THC-treated mice showed a decreased spine density at CA1 pyramidal neurons and reduced long-term potentiation at Schaffer collateral-CA1 synapses. Interestingly, an up-regulation in the expression of CB1R/5-HT2AR heterodimers was observed in the hippocampus of THC-exposed mice and a pre-treatment with the 5-HT2AR antagonist MDL 100,907 (0.01 mg/kg) prevented enhanced heterodimerization and the THC-associated memory impairment. Together, these results reveal the significance of serotonergic signalling through 5-HT2ARs in the memory-impairing effects of repeated low doses of THC.

Long-term effects of cariprazine exposure on dopamine receptor subtypes

CNS Spectrums ◽  
2013 ◽  
Vol 19 (3) ◽  
pp. 268-277 ◽  
Author(s):  
Yong Kee Choi ◽  
Nika Adham ◽  
Béla Kiss ◽  
István Gyertyán ◽  
Frank I. Tarazi
Keyword(s):  
Dopamine Receptor ◽  
Dopaminergic System ◽  
Partial Agonist ◽  
Brain Regions ◽  
Repeated Treatment ◽  
Receptor Subtypes ◽  
Long Term Effects ◽  
Tissue Sections ◽  
Preferential Binding

IntroductionAll clinically effective antipsychotics are known to act on the dopaminergic system, and previous studies have demonstrated that repeated treatment with antipsychotics produced region-specific changes in dopamine receptor levels. Cariprazine is a dopamine D3 and D2 receptor partial agonist with preferential binding to D3 receptors. We examined the effects of chronic cariprazine administration on dopamine receptor levels.MethodsRats were administered either vehicle or cariprazine (0.06, 0.2, or 0.6 mg/kg) for 28 days. Dopamine receptor levels were quantitated using autoradiographic assays on brain tissue sections from the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), caudate putamen (CPu), hippocampus (HIPP), olfactory tubercle (OT), and islands of Calleja (ICj).ResultsChronic treatment with cariprazine did not alter D1 receptor levels in any brain region tested. Cariprazine increased D2 receptor levels in mPFC (27%–43%), NAc (40%–45%), medial (41%–53%) and lateral (52%–63%) CPu, and HIPP (38%). Cariprazine dose-dependently upregulated D3 receptor levels in ICj (32%–57%), OT (27%–67%), and NAc shell (31%–48%). Repeated cariprazine treatment increased D4 receptor in NAc (53%–82%), medial (54%–98%) and lateral (58%–74%) CPu, and HIPP (38%–98%).ConclusionSimilar to other antipsychotics, cariprazine upregulated D2 and D4 receptor levels in various brain regions. Cariprazine was unique among antipsychotics in increasing D3 receptor levels, which may support its unique psychopharmacologic properties.

scholarly journals Anti-inflammatory treatment with FTY720 starting after onset of symptoms reverses synaptic and memory deficits in an AD mouse model

2019 ◽  
Author(s):  
Georgia-Ioanna Kartalou ◽  
Ana Rita Salgueiro Pereira ◽  
Thomas Endres ◽  
Angelina Lesnikova ◽  
Plinio Casarotto ◽  
...  
Keyword(s):  
Mouse Model ◽  
Pyramidal Neurons ◽  
Memory Performance ◽  
Disease Onset ◽  
Immunohistochemical Analysis ◽  
Long Term Potentiation ◽  
Spine Density ◽  
Disease Symptoms ◽  
Approved Drugs ◽  
Ad Mouse Model

AbstractTherapeutical approaches providing effective medication for Alzheimer’s disease (AD) patients after disease onset are urgently needed. Repurposing FDA approved drugs like fingolimod (FTY720) for treatment of AD is a promising way to reduce the time to bring such medication into clinical practice. Previous studies in AD mouse models suggested that physical exercise or changed lifestyle can delay AD related synaptic and memory dysfunctions when treatment started in juvenile animals long before onset of disease symptoms. Here, we addressed whether the FDA approved drug fingolimod rescues AD related synaptic deficits and memory dysfunction in an APP/PS1 AD mouse model when medication starts after onset of symptoms (at 5 months). Male mice received intraperitoneal injections of fingolimod for 1-2 months starting at 5-6 months. This treatment rescued spine density as well as long-term potentiation in hippocampal CA1 pyramidal neurons, and ameliorated dysfunctional hippocampus-dependent memory that was observed in untreated APP/PS1 animals at 6-7 months of age. Immunohistochemical analysis with markers of microgliosis (Iba1) and astrogliosis (GFAP) revealed that our fingolimod treatment regime strongly down regulated neuro-inflammation in the hippocampus and cortex of this AD model. These effects were accompanied by a moderate reduction of Aβ accumulation in hippocampus and cortex. Our results suggest that fingolimod, when applied after onset of disease symptoms in an APP/PS1 mouse model, rescues synaptic pathology and related memory performance deficits observed in untreated AD mice, and that this beneficial effect is mediated via anti-neuroinflammatory actions of the drug on microglia and astrocytes.

Effect of proglumide on rat pancreatic growth

1985 ◽  
Vol 249 (2) ◽  
pp. G294-G298
Author(s):  
T. Yamaguchi ◽  
K. Tabata ◽  
L. R. Johnson
Keyword(s):  
Low Dose ◽  
Partial Agonist ◽  
Competitive Inhibitor ◽  
Smooth Muscle Contraction ◽  
High Dose ◽  
Cell Secretion ◽  
Trophic Effect ◽  
Cck Receptors ◽  
Pancreatic Growth ◽  
Significant Stimulation

Proglumide, a glutaramic acid derivative, is a specific competitive inhibitor of gastrin and cholecystokinin (CCK) receptors. As such, it blocks gastrin-stimulated acid secretion, the trophic effect of gastrin, and CCK-stimulated smooth muscle contraction and acinar cell secretion. In the current study we have demonstrated that proglumide (100 mg/kg three times per day) blocks the trophic effect of a low dose of CCK octapeptide (300 ng/kg) given three times a day for 2 days. The same dose of proglumide when given alone for 6 days, however, resulted in a significant stimulation of pancreatic growth. Proglumide had no effect on the trophic response to a high dose of CCK-OP (5 micrograms/kg) administered for either 2 or 6 days. These results indicate that given over a period of several days proglumide behaves like a partial agonist of pancreatic growth.

Effects of indomethacin on brain blood flow, cerebral metabolism, and sagittal sinus prostanoids after hypoxia

1995 ◽  
Vol 269 (4) ◽  
pp. H1450-H1459 ◽  
Author(s):  
M. G. Coyle ◽  
W. Oh ◽  
K. H. Petersson ◽  
B. S. Stonestreet
Keyword(s):  
Blood Flow ◽  
Low Dose ◽  
Cerebral Metabolism ◽  
Brain Regions ◽  
Cerebral Hypoperfusion ◽  
High Dose ◽  
Brain Blood Flow ◽  
Newborn Piglets ◽  
Sagittal Sinus ◽  
Dose Dependent

We tested the hypotheses that during recovery from hypoxia, newborn piglets exhibit a posthypoxic cerebral hyperemia, indomethacin-pretreated piglets exhibit a posthypoxic cerebral hypoperfusion, and that the changes caused by indomethacin are dose dependent and related to the loss of prostanoids. We studied piglets exposed to 40 min of hypoxia after pretreatment with high (5 mg/kg, n = 9) or low (0.3 mg/kg, n = 8) doses of indomethacin or placebo (n = 9) and allowed to recover for 120 min. In the placebo and low-dose pretreatment groups, total and regional brain blood flow increased during hypoxia but returned to baseline 10 min after hypoxia. High-dose indomethacin pretreatment was associated with a posthypoxic hypoperfusion to certain brain regions at 10 min of recovery to values similar to those after indomethacin treatment before the onset of hypoxia. During and after hypoxia, the cerebral metabolic rate of oxygen was preserved in both the placebo and low-dose groups and decreased significantly during hypoxia in the high-dose group. Sagittal sinus prostacyclin was reduced significantly in both indomethacin-treated groups throughout the study. We conclude that a posthypoxic hyperemia is not observed in newborn piglets. This finding was not altered by pretreatment with a therapeutic dose of indomethacin, whereas a pharmacological dose was associated with selective hypoperfusion to certain brain regions both before hypoxia and during recovery from hypoxia.

scholarly journals The Rapid Effect of Bisphenol-A on Long-Term Potentiation in Hippocampus Involves Estrogen Receptors and ERK Activation

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaowei Chen ◽  
Yu Wang ◽  
Fang Xu ◽  
Xiaofei Wei ◽  
Junfang Zhang ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Learning And Memory ◽  
Low Dose ◽  
Long Term Potentiation ◽  
Gonadal Hormones ◽  
Endocrine Function ◽  
Facilitatory Effect ◽  
High Dose ◽  
Term Potentiation

Bisphenol-A (BPA), a widely used synthetic compound in plastics, disrupts endocrine function and interferes with physiological actions of endogenous gonadal hormones. Chronic effects of BPA on reproductive function, learning and memory, brain structure, and social behavior have been intensively investigated. However, less is known about the influence of BPA on long-term potentiation (LTP), one of the major cellular mechanisms that underlie learning and memory. In the present study, for the first time we investigated the effect of different doses of BPA on hippocampal LTP in rat brain slices. We found a biphasic effect of BPA on LTP in the dentate gyrus: exposure to BPA at a low dose (100 nM) enhanced LTP and exposure to BPA at a high dose (1000 nM) inhibited LTP compared with vehicle controls. The rapid facilitatory effect of low-dose BPA on hippocampal LTP required membrane-associated estrogen receptor (ER) and involved activation of the extracellular signal-regulated kinase (ERK) signaling pathway. Coadministration of 17β-estradiol (E2, the primary estrogen hormone) and BPA (100 nM) abolished both the BPA-induced enhancement of LTP and the E2-induced enhancement of baseline fEPSP, suggesting a complex interaction between BPA- and E2-mediated signaling pathways. Our investigation implies that even nanomolar levels of endocrine disrupters (e.g., BPA) can induce significant effects on hippocampal LTP.

scholarly journals Anti-PTSD Effects of Hypidone Hydrochloride (YL-0919): A Novel Combined Selective 5-HT Reuptake Inhibitor/5-HT1A Receptor Partial Agonist/5-HT6 Receptor Full Agonist

2021 ◽  
Vol 12 ◽  
Author(s):  
Wen-Gang Liu ◽  
Li-Ming Zhang ◽  
Jun-Qi Yao ◽  
Yong-Yu Yin ◽  
Xiao-Ying Zhang ◽  
...  
Keyword(s):  
Reuptake Inhibitor ◽  
Pyramidal Neurons ◽  
Partial Agonist ◽  
Synaptic Proteins ◽  
Repeated Treatment ◽  
Spine Density ◽  
Related Disorder ◽  
Full Agonist ◽  
Contextual Fear ◽  
Underlying Mechanisms

Posttraumatic stress disorder (PTSD) is a debilitating trauma and stressor-related disorder that has become a major neuropsychiatric problem, leading to substantial disruptions in individual health and societal costs. Our previous studies have demonstrated that hypidone hydrochloride (YL-0919), a novel combined selective 5-HT reuptake inhibitor/5-HT1A receptor partial agonist/5-HT6 receptor full agonist, exerts notable antidepressant- and anxiolytic-like as well as procognitive effects. However, whether YL-0919 exerts anti-PTSD effects and its underlying mechanisms are still unclear. In the present study, we showed that repeated treatment with YL-0919 caused significant suppression of contextual fear, enhanced anxiety and cognitive dysfunction induced by the time-dependent sensitization (TDS) procedure in rats and by inescapable electric foot-shock in a mouse model of PTSD. Furthermore, we found that repeated treatment with YL-0919 significantly reversed the accompanying decreased expression of the brain-derived neurotrophic factor (BDNF) and the synaptic proteins (synapsin1 and GluA1), and ameliorated the neuroplasticity disruption in the prefrontal cortex (PFC), including the dendritic complexity and spine density of pyramidal neurons. Taken together, the current study indicated that YL-0919 exerts clear anti-PTSD effects, which might be partially mediated by ameliorating the structural neuroplasticity by increasing the expression of BDNF and the formation of synaptic proteins in the PFC.

Acetaminophen: Neonatal hepatotoxicity due to late pregnancy exposure

1987 ◽  
Vol 45 ◽  
pp. 718-719
Author(s):  
G.A. Miranda ◽  
M.A. Arroyo ◽  
C.A. Lucio ◽  
M. Mongeotti ◽  
S.S. Poolsawat
Keyword(s):  
Low Dose ◽  
Fetal Liver ◽  
Late Pregnancy ◽  
Toxic Chemicals ◽  
Control Group ◽  
High Dose ◽  
Over The Counter ◽  
Liver And Kidney ◽  
Neonatal Liver ◽  
Childbearing Women

Exposure to drugs and toxic chemicals, during late pregnancy, is a common occurrence in childbearing women. Some studies have reported that more than 90% of pregnant women use at least 1 prescription; of this, 60% used more than one. Another study indicated that 80% of the consumed drugs were not prescribed, and of this figure, 95% were “over-the-counter” drugs. Acetaminophen, the safest of all over-the-counter drugs, has been reported to induce fetal liver necrosis in man and animals and to have abortifacient and embryocidal action in mice. This study examines the degree to which acetaminophen affects the neonatal liver and kidney, when a fatty diet is simultaneously fed to the mother during late pregnancy.Timed Swiss Webster female mice were gavaged during late pregnancy (days 16-19) with fat suspended acetaminophen at a high dose, HD = 84.50 mg/kg, and a low dose, LD = 42.25 mg/kg; a control group received fat alone.

Evaluation of hippocampus in rhesus monkeys after chronic (1-year) inhalation exposure to marijuana: I. Electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 398-399
Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Rhesus Monkeys ◽  
Low Dose ◽  
Inhalation Exposure ◽  
Synaptic Cleft ◽  
High Dose ◽  
Withdrawal Time ◽  
Treatment Groups ◽  
Ultrastructural Evidence ◽  
Male Rhesus

Exposure of rhesus monkeys (Macaca mulatta) to marijuana via inhalation or to intravenous delta-9-tetrahydrocannabinol (THC), reportedly caused ultrastructural evidence of increased synaptic width. Chronic marijuana smoke in a single rhesus monkey examined after a six month withdrawal time caused ultrastructure changes in the septal, hippocampal and amygdala regions; the synaptic cleft was widened, electron opaque material was found in the cleft and in the pre- and postsynaptic regions, with some clumping of the synaptic vesicles. The objective of our study was to assess neuropathological alterations produced by chronic inhalation of marijuana smoke.Nineteen male rhesus monkeys, 3-5 years of age and weighing 3-8 kg, were divided into four treatment groups: a) sham control, b) placebo smoke (7 days/ week) c) low dose marijuana (2 times/week with 5 days/week sham) and d) high dose marijuana (7 times/week). A smoke exposure consisted of smoke from one cigarette (2.6% THC) burned down to 10 mm butt length. Smoke was administered via smoke generator (ADL II, Arthur D. Little, Inc. Cambridge, MA) and nose-mouth only masks (local production) equipped with one-way valves.

Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Processes ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Semantic Retrieval ◽  
Age Related ◽  
The Face ◽  
Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

Benefit/Risk Profile of Combined Antiplatelet Therapy with Ticlopidine and Aspirin

1991 ◽  
Vol 65 (05) ◽  
pp. 504-510 ◽  
Author(s):  
Raffaele De Caterina ◽  
Rosa Sicari ◽  
Walter Bernini ◽  
Guido Lazzerini ◽  
Giuliana Buti Strata ◽  
...  
Keyword(s):  
Platelet Function ◽  
Low Dose ◽  
Bleeding Time ◽  
Ex Vivo ◽  
Stable Coronary Artery Disease ◽  
High Dose ◽  
Single Drug ◽  
Before And After ◽  
Serum Thromboxane ◽  
Artery Disease

SummaryTiclopidine (T) and aspirin (ASA) are two antiplatelet drugs both capable of prolonging bleeding time (BT), with a different mechanism of action. A synergism in BT prolongation has been reported and is currently considered an argument for not recommending their combination. However, a profound suppression of platelet function might be a desirable counterpart of a marked prolongation of BT, with a possible use in selected clinical situations. We therefore studied ex vivo platelet function (aggregation by ADP 0.5-1-2.5 μM; adrenaline 0.75-2.5 μM; collagen 1.5-150 μg/ml; arachidonic acid 1 mM; PAF 1 μM; adrenaline 0.17 μM + ADP 0.62 μM; serum thromboxane ([TX]B2 generation) and BT (Mielke) in 6 patients with stable coronary artery disease receiving such combination. Patients underwent sequential laboratory evaluations at baseline, after 7 days of T 250 mg b.i.d., before and after the intravenous administration of ASA 500 mg, respectively, and, finally, after a minimum of 7 days of sole ASA oral administration (50 mg/day). The experimental design, therefore, allowed a comparison of T and ASA effects (2nd and 4th evaluation), and an assessment of the combination effect (3rd evaluation). Platelet aggregation in response to all doses of ADP was depressed more by T than by ASA. Conversely, responses to adrenaline, and arachidonate were affected more by ASA than by T. For all other agents, differences were not significant. T + ASA combination was more effective (p <0.05) than either treatment alone in depressing responses to high-dose collagen (% over control, mean ± SEM: T: 95 ± 3; ASA: 96 ± 5; T + ASA: 89 ± 4). Serum TXB2 (basal, ng/ml: 380 ± 54) did not change with T (372 ± 36), dropped to <1 ng/ml on ASA injection and slightly re-increased to 9.1 ± 3.1 ng/ml on oral low-dose ASA. BT (basal 7.4 ± 0.6 min) was affected similarly by T (9.2 ± 0.8) or ASA (9.7 ± 0.9) alone, but increased to 15.0 ± 0.7 min on combination treatment (106% increase over control). Thus, the strong synergism in BT prolongation by ASA-T combination has a counterpart in the inhibition of platelet function in response to strong stimuli such as high-dose collagen, not otherwise affected significantly by single-drug treatment. This effect is a possible rationale for the clinical evaluation of T + ASA combination.

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