Molecular mechanisms underlying electroconvulsive therapy-induced amnestic deficits: A decade of research

Inhibition of NLRP3 inflammasome-mediated neuroinflammation alleviates electroconvulsive shock-induced memory impairment via regulation of hippocampal synaptic plasticity in depressive rats

Electroconvulsive shock has been considered one of the most effective treatment modalities for major depressive disorder. The association of acute transitory neuroinflammation in the hippocampus following electroconvulsive therapy with transient learning and memory impairment limits its clinical application. Whereas the NLRP3 inflammatory pathway is deemed to serve a key role in neuroinflammatory regulation, we aimed to examine if NLRP3 inflammasome activation was linked to electroconvulsive shock (ECS)-induced neuroinflammation and cognitive deficits. The depressed rats were modeled with chronic unpredictable mild stress. Their depression-like behaviors and cognitive performance were evaluated via sucrose preference test, forced swim test, open field test, and Morris water maze test. The NLRP3 expression was determined by western blot. The hippocampal CA1 region was immunohistochemically and electron-microscopically examined, respectively, for the activation of Iba-1 positive microglia and the ultrastructure of synapses. In this work, we found that ECS induced microglial activation in the rat hippocampal CA1 region. Pharmacological inhibition of NLRP3 inflammasome with MCC950 (NLRP3 inhibitor) in vivo significantly alleviated ECS-induced spatial learning and memory impairment, partially reversed neuroinflammation, and synaptic structural plasticity in the damaged hippocampal CA1 region, and reduced synapse associated protein expression and microglial activation. It offers a potential new approach for the prevention and treatment of cognitive decline following electroconvulsive therapy.

The Effect of Foot Reflexology on Amnesia in Patients Undergoing Electroconvulsive Therapy: A Randomized Clinical Trial

Introduction: Electroconvulsive therapy (ECT) is the oldest procedure among the early biological treatments introduced in psychiatry. However, the most debated and treatment-limiting adverse effect of ECT is amnesia. Therefore, due to the restriction of the use of drugs to manage amnesia in patients undergoing ECT, the present study investigated the effect of reflexology on amnesia.

Methods: In this randomized controlled trial, 68 patients who met the inclusion criteria were randomly allocated to intervention and control groups. The intervention group received foot reflexology with olive oil 20 minutes a day for 3 days, while the control group was given a gentle foot rub with olive oil 20 minutes a day for 3 days. The amnesia rate of all patients was measured by the Galveston Orientation and Amnesia Test (GOAT) 30 minutes after the end of ECT. The data were analyzed using SPSS software version 11.5 and t-test, chi-squared test, and repeated measures ANOVA.

Results: The results showed that reflexology significantly increased recalling scores in the intervention group compared to the control group. Foot reflexology seems to be effective in managing amnesia in patients after ECT.

Conclusion: Foot reflexology, as a relatively simple, inexpensive, and non-invasive technique with few side effects, can be used to manage amnesia in patients after ECT.

Calotropis procera: A potential cognition enhancer in scopolamine and electroconvulsive shock-induced amnesia in rats

OBJECTIVES

Present study evaluates the effect of Calotropis procera (Apocynaceae) dry latex on cognitive function in rats using scopolamine and electroconvulsive shock (ECS) induced amnesia model.

MATERIALS AND METHODS

Male Wistar rats were pretreated with 200, 400 and 800 mg/kg of C. procera dry latex in scopolamine-induced amnesia model. Dose showing maximum effect in cognitive performance was selected and further evaluated using scopolamine and ECS-induced amnesia model for its effect on neurochemical enzymes and cognitive performance. Acetylcholinesterase (AChE) activity, β amyloid1-42, and dopamine level were analyzed, while the cognitive performance was assessed by elevated plus maze, step-through passive avoidance test, and Morris water maze. Simultaneously, C. procera dry latex (25, 50, 100, 250, 500, and 1000 μg/mL) was screened for in vitro AChE inhibition assay.

RESULTS

Pretreatment with (200, 400 and 800 mg/kg) C. procera dry latex shows dose dependent increase in cognitive performance in scopolamine-induced amnesia. Further, pretreatment with the selected dose (800 mg/kg) showed significant improvement in transfer latency (P < 0.001, P < 0.01), escape latency (P < 0.05), time spent in target quadrant (P < 0.001) also significant decrease in AChE activity (P < 0.05), β amyloid1-42 level (P < 0.001), and increase in dopamine level (P < 0.01) in rat brain homogenate when compared with scopolamine and ECS disease control groups. IC50 for C. procera dry latex was found to be <1000 μg/mL.

CONCLUSIONS

Pretreatment with C. procera dry latex (800 mg/kg) produced significant cognition enhancement by improving cognitive performance and decreasing the marker neurochemical enzyme activity in scopolamine and ECS-induced amnesia model.

Investigation of the possible role of Shankapushpi in the attenuation of ECT induced amnestic deficits

INTRODUCTION

Shankapushpi (Evolvulus alsinoides and others) has received mention in traditional Indian writings as a potential enhancer of cognitive functioning. This study used an animal model to examine whether Shankapushpi improves learning and memory and attenuates anterograde and retrograde amnesia associated with electroconvulsive shocks (ECS).

MATERIALS AND METHODS

Adult, male, Sprague Dawley rats (n=64) were treated with an aqueous extract of Shankapushpi or vehicle all through the 13-day study. From Days 1 to 8, the animals received Shankapushpi or vehicle alone. On Days 8-10, the animals were trained in a T-maze. On Day 11, they received two true or sham 30 mC ECS 5 h apart. On Day 12, recall of pre-ECS training was examined, and on Day 13, new learning was assessed.

RESULTS

Shankapushpi-treated rats did not show better learning during the pre-ECS phase (Days 8-10). Seizure duration was not influenced by Shankapushpi treatment (Day 11). Shankapushpi did not attenuate ECS-induced retrograde amnesia (Day 12). ECS did not impair new learning, and the effect of Shankapushpi herein, therefore, could not be ascertained (Day 13).

CONCLUSIONS

In this animal model of learning and memory, and of ECS-induced retrograde amnesia, Shankapushpi was found to have no favorable or unfavorable effects on either cognitive or seizure duration parameters. These findings diminish expectations of cognitive and anticonvulsant benefits of simple Shankapushpi decoctions in clinical settings, but do not preclude benefits with extracts obtained and concentrated by using other methods.

Administration of a selective glucocorticoid antagonist attenuates electroconvulsive shock-induced retrograde amnesia

Mifepristone, a glucocorticoid and progesterone receptor antagonist, has been shown to attenuate retrograde amnesia induced by repeated electroconvulsive shocks (ECS). We examined the efficacy of CORT 108297, a selective glucocorticoid antagonist, in this regard. Adult, male, Wistar rats (n = 69) received either vehicle or CORT 108297 (1 mg/kg) 2 h before each of 5 once-daily true or sham 30 mC ECS. Recall of previous exposure to a noxious stimulus in a passive avoidance (step-through) paradigm was tested 1 day after the 5-ECS course. Analyses were conducted using recall operationalized in different ways: using the absolute final latency scores; defining adequate recall as a final latency of 30 s or greater; defining perfect recall as a final latency of 180 s; and using visual, subjective assessments of animal behavior. ECS was associated with significant impairment of recall, and this impairment was significantly attenuated by CORT 108297 on all outcome measures (with the exception of the perfect recall analyses, where outcomes narrowly missed statistical significance). In conclusion, these findings strengthen previous data from our laboratory implicating glucocorticoid mechanisms in ECS-induced retrograde amnesia. We suggest that the administration of a selective glucocorticoid receptor antagonist shortly before electroconvulsive therapy (ECT) treatments may attenuate the deleterious effect of ECT-induced acute hypercortisolemia on neural mechanisms involved in learning and memory.

How antidepressant drugs act: A primer on neuroplasticity as the eventual mediator of antidepressant efficacy

Depression is conventionally viewed as a state of chemical imbalance, and antidepressants are suggested to act through increasing monoaminergic neurotransmission. These views are currently considered simplistic. This article examines the animal and human literature on the neurohistological mechanisms underlying stress, depression and antidepressant treatment. Pathological stress and depression are associated with changes such as loss of dendritic spines, shrinkage of the dendritic tree and loss of synapses in the hippocampus and prefrontal cortex. There is also a decrease in glia. Apoptosis may occur under extreme circumstances. In contrast, there is increased dendritic arborization and synaptogenesis in the amygdala. Antidepressant treatment protects against and even reverses some but not all of these stress-induced neurohistological changes. Pathological stress results in an aberrant neuroplasticity response characterized by abnormally increased activity in the amygdala and by impaired functioning of the hippocampus, prefrontal cortex and downstream structures. This aberrant neuroplasticity response directly explains most of the clinical symptoms of depression. Antidepressant treatment protects against stress-induced pathoplastic neurohistological and neurocognitive changes. Antidepressant treatment also restores functional neuroplasticity in stressed organisms and, thereby, presumably, facilitates re-adaptation through learning and memory mechanisms. Thus, the stress-depression syndrome and the therapeutic and prophylactic efficacy of antidepressant treatments can be explained through a hardwiring analogy. In this context, glutamate is an important neurotransmitter.

Electroconvulsive therapy-induced persistent retrograde amnesia: could it be minimised by ketamine or other pharmacological approaches?

BACKGROUND

Certain pharmacological agents administered during electroconvulsive therapy may have the potential to prevent persistent retrograde amnesia induced during electroconvulsive therapy. This review examines mechanisms for electroconvulsive therapy-induced retrograde amnesia, and evaluates the suitability of the anaesthetic ketamine for preventing this amnestic outcome.

METHODS

A review of human studies, animal models and theoretical models in light of memory dysfunction following electroconvulsive therapy was conducted. MEDLINE was searched from 1950 to April 2009 using the MeSH terms "electroconvulsive therapy", "memory", "memory short term", "memory disorders", "excitatory amino acid antagonists", and "ketamine". PREMEDLINE was searched using the terms "electroconvulsive therapy", "amnesia" and "ketamine". Additional keyword and reference list searches were performed. No language, date constraints or article type constraints were used.

RESULTS

Disruption of long term potentiation as a mechanism for electroconvulsive therapy-induced retrograde amnesia is well supported. Based on this putative mechanism, an N-methyl-D-aspartate receptor antagonist would appear suitable for preventing the retrograde amnesia. Available evidence in animals and humans supports the prediction that ketamine, an anaesthetic agent and N-methyl-D-aspartate receptor antagonist, could effectively prevent electroconvulsive therapy-induced persistent retrograde amnesia. Whilst there are concerns about the use of ketamine with electroconvulsive therapy, such as possible psychotomimetic effects, on balance this anaesthetic agent may improve or hasten clinical response to electroconvulsive therapy.

CONCLUSIONS

A clinical trial is warranted to determine if ketamine anaesthesia during electroconvulsive therapy can lessen persistent retrograde amnesia and improve therapeutic response. Electroconvulsive therapy with ketamine anaesthesia may provide effective antidepressant action with minimal side effects.

Initiatives in biological research in Indian psychiatry

Biological psychiatry is an exploratory science for mental health. These biological changes provide some explicit insight into the complex area of 'brain-mind and behavior'. One major achievement of research in biological field is the finding to explain how biological factors cause changes in behavior. In India, we have a clear history of initiatives in research from a biological perspective, which goes back to 1958. In the last 61 years, this field has seen significant evolution, precision and effective utilization of contemporary technological advances. It is a matter of great pride to see that in spite of difficult times in terms of challenges of practice and services, administration, resource, funding and manpower the zest for research was very forthcoming. There was neither dedicated time nor any funding for conducting research. It came from the intellectual insight of our fore fathers in the field of mental health to gradually grow to the state of strategic education in research, training in research, international research collaborations and setting up of internationally accredited centers. During difficult economic conditions in the past, the hypothesis tested and conclusions derived have not been so important. It is more important how it was done, how it was made possible and how robust traditions were established. Almost an entire spectrum of biological research has been touched upon by Indian researchers. Some of these are electroconvulsive therapy, biological markers, neurocognition, neuroimaging, neuroendocrine, neurochemistry, electrophysiology and genetics. A lot has been published given the limited space in the Indian Journal of Psychiatry and other medical journals published in India. A large body of biological research conducted on Indian patients has also been published in International literature (which I prefer to call non-Indian journals). Newer research questions in biological psychiatry, keeping with trend of international standards are currently being investigated by the younger generation with great enthusiasm. What we have achieved so far is the foundation work in last 60 years. Our main challenge in development of biological psychiatry research in India remains resources in terms of manpower, funding and dedicated time for research psychiatrists. Developing basic sciences laboratories, discrete research questions, high quality methodology, and logistical support are some of the essentials. In the present time the culture of research has changed. It is specific and evidence-based. We have time-tested examples of International collaborative research. We need to get more resources, develop education, collaboration and effective leadership. In times to come, India will provide international leadership in basic and clinical biological psychiatry. There is hope.

Indian Journal of Psychiatry and psychiatric research in India: Past, Present and Future

Commendable work has been done in psychiatric research in India as it moves in tandem with contemporary trends abroad. Indian Journal of Psychiatry (IJP), as its flag-ship publication, has mirrored this trend faithfully down the decades. Stalwarts and icons of Indian psychiatry have set Indian research firmly on this course. A systematic appraisal of psychiatric research in India shows that most work is replicative, some of it corrective at the local level, and very little that is original and corrective at the international level. Opinion and policy makers, including IJP and research departments at colleges and universities, must endeavor to steer the course towards trend-setting and original work emanating from India, even as we do not neglect replicative work, of which we are masters.

Cognitive psychiatry in India

Cognitive deficits have been shown to exist in various psychiatric disorders. Though most Indian studies pertaining to cognition have been replication studies, well designed original studies have also been conducted. This article traces the evolution of cognitive psychiatry in India. Cognitive research has huge potential in India and can help us unravel mysteries of the human mind, identify etiopathogenesis and facilitate treatment of psychiatric disorders.