Development of an animal model of fluoxetine akathisia

Revisiting Antipsychotic-induced Akathisia: Current Issues and Prospective Challenges

BACKGROUND

Akathisia continues to be a significant challenge in current neurological and psychiatric practice. Prompt and accurate detection is often difficult and there is a lack of consensus concerning the neurobiological basis of akathisia. No definitive treatment has been established for akathisia despite numerous preclinical and clinical studies.] Method: We reviewed antipsychotic-induced akathisia including its clinical presentation, proposed underlying pathophysiology, current and under investigation therapeutic strategies.

CONCLUSION

Despite the initial promise that second generation antipsychotics would be devoid of akathisia effects, this has not been confirmed. Currently, there are limited therapeutic options for the clinical practice and the evidence supporting the most widely used treatments (beta blockers, anticholinergic drugs) is still absent or inconsistent.

The restless legs syndrome

The restless legs syndrome (RLS) is one of the commonest neurological sensorimotor disorders at least in the Western countries and is often associated with periodic limb movements (PLM) during sleep leading to severe insomnia. However, it remains largely underdiagnosed and its underlying pathogenesis is presently unknown. Women are more affected than men and early-onset disease is associated with familial cases. A genetic origin has been suggested but the mode of inheritance is unknown. Secondary causes of RLS may share a common underlying pathophysiology implicating iron deficiency or misuse. The excellent response to dopaminegic drugs points to a central role of dopamine in the pathophysiology of RLS. Iron may also represent a primary factor in the development of RLS, as suggested by recent pathological and brain imaging studies. However, the way dopamine and iron, and probably other compounds, interact to generate the circadian pattern in the occurrence of RLS and PLM symptoms remains unknown. The same is also the case for the level of interaction of the two compounds within the central nervous system (CNS). Recent electrophysiological and animals studies suggest that complex spinal mechanisms are involved in the generation of RLS and PLM symptomatology. Dopamine modulation of spinal reflexes through dopamine D3 receptors was recently highlighted in animal models. The present review suggests that RLS is a complex disorder that may result from a complex dysfunction of interacting neuronal networks at one or several levels of the CNS and involving numerous neurotransmitter systems.

Acute Akathisia Associated With Quetiapine Use

Because of their better side-effect profile, atypical antipsychotic agents have replaced conventional antipsychotic agents as the first-line treatment for schizophrenia. Although atypical agents are less likely to be associated with extrapyramidal symptoms, such symptoms sometimes do occur in patients treated with atypical agents. The authors report the cases of two patients who developed akathisia after treatment with quetiapine for insomnia, consider previously reported cases of akathisia induced by atypical antipsychotic agents, discuss other medications that can induce similar symptoms, discuss treatments for akathisia, and examine issues in the use of quetiapine as a soporific agent.

Animal models of acute drug-induced akathisia - a review

Akathisia is a complex neurobehavioural side effect of neuroleptics and some other drugs which is characterised by subjective report and objective manifestations of restlessness. Its pathophysiology is poorly understood and there are many limitations to its investigation in humans. This paper reviews the various attempts that have been made in modelling acute akathisia in animals. Homologous as well as isomorphic models have been attempted, but most models are partial as they reproduce either the subjective or the objective features of the syndrome. None of the available models has been fully validated. Neuroleptic-induced defecation in the rat, even though constrained by a lack of symptom similarity and thereby face validity, has been most studied as a model of subjective akathisia. Rat models of restlessness, in particular those involving the use of serotonergic drugs or lesions of the ventral tegmentum or medial prefrontal cortex, are interesting partial models that should be further investigated. Neuroleptic-induced akathisia is observed in primates and has been modelled in dogs, and these should be studied further for their validation. It is also necessary to consider the subtypes of akathisia in the attempts to develop these models.

Development of an affordable hi-resolution activity monitor system for laboratory animals

We describe a hardware and software system for recording and analyzing the spatial and temporal pattern of locomotor activity of laboratory animals. The system offers maximal spatial resolution 500-fold greater than existing light beam monitors. An infrared motion analysis systems (MacReflex, Qualysis) simultaneously tracks the location of up to 20 subjects (identified by reflective markers) to within 0.04 mm at a rate of up to 50 Hz. Macintosh software provides measures of distance traveled, amount of area traversed, number of position changes (microevents), average time between movements, number of left and right turns, number of forward movements and reversals, as well as temporal and spatial scaling exponents. This system was validated by comparing these parameters to direct observer scoring of video tapes and other commercially available activity monitors. Our findings show that applying reflective markers to the subjects does not significantly alter activity levels. The effect of pharmacological manipulation with d-amphetamine is provided to show the value of the different activity parameters. The main advantages of this system are very high spatial resolution, capacity to monitoring up to 20 animals simultaneously at reasonable cost, and lack of sensitivity of the system to ambient lighting. The main limitation is the need to apply reflective markers.