Role of platelet activating factor in triazolobenzodiazepines-induced retrograde amnesia

Re-Assessing the Role of Platelet Activating Factor and Its Inflammatory Signaling and Inhibitors in Cancer and Anti-Cancer Strategies

Since 2000s, we have outlined the multifaceted role of inflammation in several aspects of cancer, via specific inflammatory mediators, including the platelet activating factor (PAF) and PAF-receptor (PAFR) related signaling, which affect important inflammatory junctions and cellular interactions that are associated with tumor-related inflammatory manifestations. It is now well established that disease-related unresolved chronic inflammatory responses can promote carcinogenesis. At the same time, tumors themselves are able to promote their progression and metastasis, by triggering an inflammation-related vicious cycle, in which PAF and its signaling play crucial role(s), which usually conclude in tumor growth and angiogenesis. In parallel, new evidence suggests that PAF and its signaling also interact with several inflammation-related cancer treatments by inducing an antitumor immune response or, conversely, promoting tumor recurrence. Within this review article, the current knowledge and future perspectives of the implication of PAF and its signaling in all these important aspects of cancer are thoroughly re-assessed. The potential beneficial role of PAF-inhibitors and natural or synthetic modulators of PAF-metabolism against tumors, tumor progression and metastasis are evaluated. Emphasis is given to natural and synthetic molecules with dual anti-PAF and anti-cancer activities (Bio-DAPAC-tives), with proven evidence of their antitumor potency through clinical trials, as well as on metal-based anti-inflammatory mediators that constitute a new class of potent inhibitors. The way these compounds may promote anti-tumor effects and modulate the inflammatory cellular actions and immune responses is also discussed. Limitations and future perspectives on targeting of PAF, its metabolism and receptor, including PAF-related inflammatory signaling, as part(s) of anti-tumor strategies that involve inflammation and immune response(s) for an improved outcome, are also evaluated.

Bergenin ameliorates cognitive deficits and neuropathological alterations in sodium azide-induced experimental dementia

Background: Bergenin, 4-O-methyl gallic acid glucoside, is a bioactive compound found in the cortex of Mallotus japonicus (L.f.) Müll.Arg. along with many other natural resources including that from Bergenia species. The present study delineates the neuroprotective potential of bergenin through the modulation of PPAR-γ receptors. Method: Dementia was induced in the Wistar rats by intraperitoneal (i.p.) administration of sodium azide (12.5 mg/kg for the first 5 days followed by 10 mg/kg for the next 9 days). The rats were then exposed to the Morris water maze test to assess the effect on cognitive abilities followed by a series of biochemical and histopathological evaluations. Results: Sodium azide-treated rats exhibited a severe deterioration of memory as suggested by poor performance in the spatial learning task in addition to the enhancement of brain acetylcholinesterase potential, oxidative stress, inflammation, and amyloid-β (Aβ) accumulation. Administration of bergenin to sodium azide-treated rats significantly recovered cognition and related biochemical variations. Further, co-administration of Bisphenol A diglycidyl ether (BADGE), a PPAR-γ antagonist with bergenin challenged its neuroprotective effects. Conclusions: The findings of our study exhibit that the cognitive restoration potential of bergenin may be attributed to its modulatory effects against cholinesterase, oxidative stress, and inflammatory markers, as well as its neuroprotective actions, thus aligning it as a possible therapy for Alzheimer's disease-related dementia. The study also fortifies the significance of PPAR-γ receptors in dementia.

Immediate retrograde amnesia induced by midazolam: A prospective, non-randomised cohort study

BACKGROUND

Midazolam, a short-acting benzodiazepine, has sedative, anxiolytic, amnestic and anticonvulsant effects. Given its advantages of rapid onset, short duration and low toxicity, midazolam is optimal for any procedural sedation. Midazolam is known to cause anterograde amnesia; however, the possibility of retrograde amnesia has also been raised. This prospective cohort, non-randomised study evaluated the presence and extent of retrograde amnesia induced by midazolam during caesarean delivery.

METHODS

One hundred parturients scheduled for elective caesarean delivery under spinal anaesthesia were enrolled. As soon as giving birth, six picture cards were shown to the patients in 1-min intervals, and then midazolam (0.1 mg/kg) was given or not according to the patients' preference. This overall retrograde recall rate of six cards was the primary outcome of our study, which was asked by a blinded investigator.

RESULTS

The overall retrograde card recall rate was lower in the midazolam group compared with the control group (77.0 ± 13.4 vs. 87.7 ± 3.9%, P < .001), especially at 1 minute before midazolam administration (58% vs. 88%, P < .001). Decreased memory trend was observed as time progressed towards midazolam administration in the midazolam group (P = .035). More patients answered 'yes' to the factitious event in the midazolam group than in the control group (26% vs. 4%, P = .004).

CONCLUSION

Intravenous midazolam could cause a brief-period retrograde amnesia in visual and event memory. Moreover, there were more spurious reports of intraoperative factitious events in the midazolam group, implying that episodic memories were also affected by midazolam.

Anti-Alzheimer activity of isolated karanjin from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f

Aim:

The aim of this study is to find out the anti-Alzheimer’s activity of isolated karanjin and embelin.

Materials and Methods:

Karanjin isolated from Pongamia pinnata (L.) pierre and embelin from Embelia ribes Burm.f. and their purity was confirmed by ultraviolet spectrophotometric and Thin layer chromatography based study. Anti-Alzheimer’s activity of isolated compounds were evaluated through elevated plus maze and Morris water maze model on Swiss albino mice. Diazepam (1 mg/kg body weight, intraperitoneally) was used for the induction of Alzheimer’s like effects (amnesia) on Swiss albino mice and piracetam (200 mg/kg body weight, oral) used as a standard treatment.

Results:

In EPM, embelin and karanjin decrease the transfer latency time in dose dependent manner and escape latency time in MWM method. A significant (P < 0.01) reduction in amnesia with an anti-Alzheimer’s effect found when results of isolated compounds were compared with standard and vehicle control. Diazepam (1 mg/kg) treated group showed significant increase in escape latency and transfer latency when compared with vehicle control; which indicates impairment in learning and memory.

Conclusion:

Both isolated compounds and standard significantly reversed the amnesia induced by diazepam and improved learning and memory of mice in dose and time dependent manner. This study supports the ethnobotanical use of these two plants in India for the management of nerve or brain related problems.

Bacopa monniera selectively attenuates suppressed Superoxide dismutase activity in Diazepam induced amnesic mice

BACKGROUND

Amnesia is characterized by loss of memory that could result from abnormal neuro-chemical homeostasis, genetic predisposition or drug abuse. We earlier reported that B. monniera attenuates diazepam, scopolamine and L-NNA induced amnesia and wanted to test if SOD levels were affected by its administration.

PURPOSE

B. monniera is earlier reported to augment the defense system for oxidative stress by increasing the activities of superoxide dismutase, therefore, we investigated its levels after B. monniera administration in combination with different amnesic agents.

METHODS

We treated mice with amnesic agents such as scopolamine, diazepam, L-NNA and MK 801 either with or without B. monniera.

RESULTS

Diazepam (1.75 mg/kg ip) significantly reduced SOD activity while it was unaltered when Scopolamine (0.1 mg/kg ip), MK 801 (0.17 mg/kg ip) and L-NNA (30 mg/kg ip) were administered. B. monniera significantly attenuated diazepam induced suppression of SOD activity.

CONCLUSION

It is suggested that the mechanism of B. monniera's antiamnesic effect may vary depending on the type of amnesic agent used. However, antioxidant mechanism may be central to evoking the memory enhancing effects of B. monniera against diazepam induced amnesia.

Midazolam impairs acquisition and retrieval, but not consolidation of reference memory in the Morris water maze

Amnesia is one of the most discussed properties of the benzodiazepine class of drugs. The effects of benzodiazepines on human memory are usually anterograde, while changes in retrograde memory functions were seldom reported. Such inconsistent findings have prompted numerous animal studies investigating the influences of these positive modulators of inhibitory neurotransmission on different stages of memory. Among the benzodiazepines, memory effects of midazolam are of special interest due to its many and varied clinical applications. The present Morris water maze study in adult male Wistar rats was performed in three experiments in which midazolam was administered at doses of 0.5, 1 and 2 mg/kg intraperitoneally, before or immediately after each of five daily learning sessions, with two trials in a session, as well as before the probe test. Midazolam impaired acquisition and subsequent retention of spatial learning of the position of the hidden platform even at a pre-training dose of 0.5 mg/kg. This low dose was not associated with impairment of the procedural component of learning, manifested by increased time spent in the periphery of the pool. The lack of midazolam effect on consolidation has not been confounded by the observed below-chance performance of the control group since our additional experiment using diazepam also administered immediately after each of five learning sessions has revealed a similar pattern of results. Finally, midazolam administered before the probe test impaired retrieval of reference memory at all tested doses. Hence, induction of retrograde, besides anterograde amnesia should be kept in mind as a possibility when midazolam is used in clinical settings.

Amyloid-beta42 signals tau hyperphosphorylation and compromises neuronal viability by disrupting alkylacylglycerophosphocholine metabolism

Perturbation of lipid second messenger networks is associated with the impairment of synaptic function in Alzheimer disease. Underlying molecular mechanisms are unclear. Here, we used an unbiased lipidomic approach to profile alkylacylglycerophosphocholine second messengers in diseased tissue. We found that specific isoforms defined by a palmitic acid (16:0) at the sn-1 position, namely 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16:0 PAF) and 1-O-hexadecyl-sn-glycero-3-phosphocholine (C16:0 lyso-PAF), were elevated in the temporal cortex of Alzheimer disease patients, transgenic mice expressing human familial disease-mutant amyloid precursor protein, and human neurons directly exposed to amyloid-beta(42) oligomers. Acute intraneuronal accumulation of C16:0 PAF but not C16:0 lyso-PAF initiated cyclin-dependent kinase 5-mediated hyperphosphorylation of tau on Alzheimer disease-specific epitopes. Chronic elevation caused a caspase 2 and 3/7-dependent cascade resulting in neuronal death. Pharmacological inhibition of C16:0 PAF signaling, or molecular strategies increasing hydrolysis of C16:0 PAF to C16:0 lyso-PAF, protected human neurons from amyloid-beta(42) toxicity. Together, these data provide mechanistic insight into how disruptions in lipid metabolism can determine neuronal response to accumulating oligomeric amyloid-beta(42).

Bacopa monniera exerts antiamnesic effect on diazepam-induced anterograde amnesia in mice

RATIONALE

As Benzodiazepines are known to produce amnesia by involvement of the GABAergic system, we examined Bacopa monniera, an herb known for memory enhancement for reversal of memory deficits caused by diazepam.

OBJECTIVES

The objective of the study was to study the effect of standardized extract of B. monniera on diazepam-induced amnesia in mice using Morris water maze.

MATERIALS AND METHODS

We used the rota rod test as a screening measure for muscle incoordination followed by the Morris water maze scale to evaluate the effect of B. monniera on amnesia. The index of acquisition and retrieval was recorded with varying doses of Bacopa.

RESULTS

The results revealed antiamnesic effects of B. monniera (120 mg kg(-1) oral) on diazepam (1.75 mg kg(-1) intraperitoneal)-induced amnesia. The degree of reversal by Bacopa was significant as it progressively reduced escape latency time when mice treated with diazepam were subjected to acquisition trials.

CONCLUSIONS

The antiamnesic effects of Bacopa suggest likely a gamma-aminobutyric acid-benzodiazepine pathway possibly affecting long-term potentiation.

Bacopa monniera ameliorates amnesic effects of diazepam qualifying behavioral-molecular partitioning

Benzodiazepines are known to produce amnesia by involvement of GABAergic system and by interference of long term potentiation (LTP). In this study, we examined effect of Bacopa monniera on downstream molecules of LTP after diazepam-induced amnesia in mice. We used a Morris water maze scale for evaluating the effect of Bacopa monniera after screening for muscle coordination by rota rod. The index of acquisition and retrieval was recorded as escape latency time (ELT). Behavioral results showed that Bacopa monniera (120 mg kg(-1) oral) significantly reversed diazepam- (1.75 mg kg(-1) i.p.) induced amnesia in Morris water maze task. The molecular studies revealed that diazepam upregulated mitogen activated protein kinase (MAP kinase), phosphorylated CREB (pCREB) and inducible nitric oxide synthase (iNOS), while it downregulated nitrite, nitrate, total nitrite, cAMP response element binding protein (CREB) expression, phosphodiesterase, cyclic adenosine monophosphate (cAMP) without affecting calmodulin levels. Bacopa monniera suppressed the diazepam induced upregulation of MAP kinase, pCREB and iNOS and attenuated the downregulation of nitrite. It did not affect the cAMP, PDE, nitrate, total nitrite, total CREB level. These behavioral findings displayed the reversal of diazepam-induced amnesia by Bacopa monniera without qualifying the molecular details although some downstream molecules of LTP may be involved.

Potentiation of Ethanol in Spatial Memory Deficits Induced by Some Benzodiazepines

Triazolam caused no significant increase in the total error at 0.05 and 0.1 mg/kg. However, at 0.2 mg/kg, it caused a significant increase in total error. Almost the same findings were observed with brotizolam and rilmazafone. That is, at 0.2 and 0.5 mg/kg of brotizolam, 0.5 and 1.0 mg/kg of rilmazafone caused no significant increase in the total error. However, brotizolam at 1.0 mg/kg and rilmazafone at 2.0 mg/kg caused a significant increase in total error. Triazolam (0.05 mg/kg) and ethanol (1.0 g/kg) showed no significant effect on the numbers of errors when used alone separately, but the simultaneous use of triazolam and ethanol caused a significant increase in total error. Almost the same findings were observed with the coadministration of brotizolam (0.2 mg/kg) or rilmazafone (0.5 mg/kg) with ethanol. These results clearly indicate that all the short-acting benzodiazepines used in the study showed potentiation by ethanol in spatial memory deficits in mice.

Criminal injury case using vegetable juice intermixed with triazolam

This article explores an injury case in which a middle-aged male offered two female colleagues vegetable juice containing triazolam. The concentration of triazolam in one subject's vegetable juice was of a higher concentration than the other. This subject suffered from such symptoms as numbness, sleepiness, visual disturbance and anterograde amnesia. Conversely, despite having consumed a considerable quantity of vegetable juice, the other subject, with a relatively lower concentration of triazolam in her drink carton, exhibited no symptoms. The differences in the amount of triazolam ingested by each subject, particularly with respect to the expression of symptoms in just one subject, sparked considerable medico-legal discussion. The advice of a medico-legal expert was thus required to explain the reason for these differences.