Electroconvulsive shock prevents dopamine receptor supersensitivity

Combination therapy of modified electroconvulsive therapy and long-acting injectable aripiprazole for dopamine supersensitivity psychosis: a case report

In the treatment of schizophrenia, long-term pharmacotherapy with D2-receptor antagonists can induce dopamine supersensitivity psychosis (DSP). We report a male patient with schizophrenia with suspected DSP due to excessive polypharmacy. He was hospitalized for several years. Most psychotropic drugs were reduced and subsequently stopped without the exacerbation of symptoms by administering modified electroconvulsive therapy (mECT). Aripiprazole was then selected as the main drug for treatment, which was subsequently changed to the long-acting injection formulation. He was eventually discharged and returned home. Combination therapy with mECT and aripiprazole, especially the long-acting injectable formulation, may help improve and prevent DSP.

Effects of repeated electroconvulsive shocks on dopamine supersensitivity psychosis model rats

While the long-term administration of antipsychotics is known to cause dopamine supersensitivity psychosis (DSP), recent studies revealed that DSP helps form the foundation of treatment resistance. Electroconvulsive shock (ES) is one of the more effective treatments for treatment-resistant schizophrenia. The objective of this study was to examine whether repeated ES can release rats from dopamine supersensitivity states such as striatal dopamine D2 receptor (DRD2) up-regulation and voluntary hyperlocomotion following chronic administration of haloperidol (HAL). HAL (0.75 mg/kg/day) was administered for 14 days via mini-pumps implanted in rats, and DRD2 density and voluntary locomotion were measured one day after drug cessation to confirm the development of dopamine supersensitivity. The rats with or without dopamine supersensitivity received repeated ES or sham treatments, and then DRD2 density was assessed and a voluntary locomotion test was performed. Chronic treatment with HAL led to the up-regulation of striatal DRD2 and hyperlocomotion in the rats one day after drug cessation. We thus confirmed that these rats experienced a dopamine supersensitivity state. Moreover, after repeated ES, locomotor activity and DRD2 density in the DSP model rats fell to the control level, while an ES sham operation had no effect on the dopamine supersensitivity state. The present study suggests that repeated ES could release DSP model rats from dopamine supersensitivity states. ES may be helpful for patients with DSP.

Antipsychotic-Induced Dopamine Supersensitivity Psychosis: Pharmacology, Criteria, and Therapy

The first-line treatment for psychotic disorders remains antipsychotic drugs with receptor antagonist properties at D2-like dopamine receptors. However, long-term administration of antipsychotics can upregulate D2 receptors and produce receptor supersensitivity manifested by behavioral supersensitivity to dopamine stimulation in animals, and movement disorders and supersensitivity psychosis (SP) in patients. Antipsychotic-induced SP was first described as the emergence of psychotic symptoms with tardive dyskinesia (TD) and a fall in prolactin levels following drug discontinuation. In the era of first-generation antipsychotics, 4 clinical features characterized drug-induced SP: rapid relapse after drug discontinuation/dose reduction/switch of antipsychotics, tolerance to previously observed therapeutic effects, co-occurring TD, and psychotic exacerbation by life stressors. We review 3 recent studies on the prevalence rates of SP, and the link to treatment resistance and psychotic relapse in the era of second-generation antipsychotics (risperidone, paliperidone, perospirone, and long-acting injectable risperidone, olanzapine, quetiapine, and aripiprazole). These studies show that the prevalence rates of SP remain high in schizophrenia (30%) and higher (70%) in treatment-resistant schizophrenia. We then present neurobehavioral findings on antipsychotic-induced supersensitivity to dopamine from animal studies. Next, we propose criteria for SP, which describe psychotic symptoms and co-occurring movement disorders more precisely. Detection of mild/borderline drug-induced movement disorders permits early recognition of overblockade of D2 receptors, responsible for SP and TD. Finally, we describe 3 antipsychotic withdrawal syndromes, similar to those seen with other CNS drugs, and we propose approaches to treat, potentially prevent, or temporarily manage SP.

The role of dopamine in epilepsy

The clinical benefits of dopamine agonists in the management of epilepsy can be traced back over a century, whilst the introduction of neuroleptics into psychiatry practice 40 years ago witnessed the emergence of fits as a side effect of dopamine receptor blockade. Epidemiologists noticed a reciprocal relationship between the supposed dopaminergic overactivity syndrome of schizophrenia and epilepsy, which came to be regarded as a dopamine underactivity condition. Early pharmacological studies of epilepsy employed nonselective drugs, that often did not permit dopamine's antiepileptic action to be clearly dissociated from that of other monoamines. Likewise, the biochemical search for genetic abnormalities in brain dopamine function, as predeterminants of spontaneous epilepsy, proved largely inconclusive. The discovery of multiple dopamine receptor families (D1 and D2), mediating opposing influences on neuronal excitability, heralded a new era of dopamine-epilepsy research. The traditional anticonvulsant action of dopamine was attributed to D2 receptor stimulation in the forebrain, while the advent of selective D1 agonists with proconvulsant properties revealed for the first time that dopamine could also lower the seizure threshold from the midbrain. Whilst there is no immediate prospect of developing D2 agonists or D1 antagonists as clinically useful antiepileptics, there is a growing awareness that seizures might be precipitated as a consequence of treating other neurological disorders with D2 antagonists (schizophrenia) or D1 agonists (parkinsonism).

Dopamine D2 receptors: a potential pharmacological target for nomifensine and tranylcypromine but not other antidepressant treatments

Treatment for 1 or 14 days by IP injection with the antidepressants, amitriptyline (10 mg/kg), bupropion (30 mg/kg), desipramine (10 mg/kg), GBR 12909 (10 mg/kg), sibutramine HCl (3 mg/kg), mianserin (5 mg/kg), and zimeldine (10 mg/kg), did not affect the number or affinity of dopamine D2 receptors determined by [3H]raclopride binding to rat striatal membranes. Similarly, neither did a single, nor repeated (five times over 10 days), electroconvulsive shock, given under halothane anaesthesia, have any effect on [3H]raclopride binding parameters. By contrast, the noradrenaline and dopamine reuptake inhibitor, nomifensine (5 mg/kg), and the monoamine oxidase inhibitor, tranylcypromine (5 mg/kg), decreased the number of dopamine D2 receptors by 12% and 11%, respectively, when given for 14 days. Administration of the D2 receptor antagonist, haloperidol (1 mg/kg), for 14 days increased the number of [3H]raclopride binding sites by 17%. Thus, the data demonstrate that although nomifensine and tranylcypromine decrease D2 receptor number after 14 days administration, this adaptive change is not observed with other antidepressant treatments. However, the findings do not preclude a contribution of altered dopamine D2 receptor function to the efficacy of those drugs with potent effects on dopaminergic neuronal function.

Effects of chronic electroconvulsive shock on interstitial concentrations of dopamine in the nucleus accumbens

There is accumulating evidence that chronic electroconvulsive shock (ECS) can increase the functional output of central dopaminergic systems. The present experiments investigated the effects of acute and chronic ECS on interstitial concentrations of dopamine (DA) in the nucleus accumbens (NAC) using in vivo microdialysis in awake freely moving rats. ECS (150 V, 0.75 s) increased interstitial concentrations of DA, DOPAC and HVA to approximately 130% of baseline values. The magnitude of the ECS-induced increase in DA was not affected by chronic ECS. In contrast, the response of the DA metabolites was attenuated in the chronic ECS group. Chronic ECS did not influence apomorphine (25 micrograms/kg, SC)-induced decreases in extracellular concentrations of DA or its metabolites in the NAC, thus providing no support for the hypothesis that chronic ECS produces subsensitivity of DA autoreceptors. d-Amphetamine (1.5 mg/kg SC)-induced increases in extracellular DA were significantly prolonged in the NAC of the chronic ECS group. In accordance with previous reports, the locomotor stimulant effects of d-amphetamine were also enhanced in the chronic ECS group. These data provide further evidence that chronic ECS can increase certain behavioral and neurochemical indices of meso-accumbens DA function.

Localized alterations of dopamine receptor binding in rat brain by repeated electroconvulsive shock: an autoradiographic study

The effects of repeated electroconvulsive shock (ECS) on binding parameters of D1 and D2 type dopamine (DA) receptors were investigated in different brain regions of male rats using quantitative autoradiography. D1 binding was studied with [3H]SCH 23390 as the ligand and D2 binding with [3H]spiroperidol. The distribution patterns of both D1 and D2 receptor sites were in good agreement with previously published reports. Repeated ECS induced upregulation of D1 receptors in the olfactory tubercle, the endopiriform nucleus and the substantia nigra without appreciably affecting D1 binding sites in the striatum, n. accumbens or in other brain regions containing D1 binding sites. Upregulation of D2 binding sites, after ECS, was seen in the accumbens, the olfactory tubercle, the amygdaloid nuclei, the claustrum and the endopiriform nucleus, but not in the caudate-putamen or in other brain regions containing D2 binding sites. The present finding that repeated ECS can selectively upregulate DA receptor binding sites in discrete brain areas, including limbic structures, renders important support to a large number of previous studies that demonstrated effects of repeated ECS on DA receptor function in behavioral models.

ECT and tardive dyskinesia

Three cases of elderly depressed patients with symptoms of tardive dyskinesia (TD) subsequently treated with electroconvulsive therapy (ECT) are presented. These cases are discussed in relation to several cases reported in the literature of ECT and TD. The possibility of improvement in symptoms of TD in certain patients is discussed.

Effects of chronic electroconvulsive shock on D1 and D2 dopamine receptor-mediated activity of adenylate cyclase in homogenates of striatum and limbic forebrain of rat

Stimulation of adenylate cyclase by dopamine in homogenates of the striatum was unaltered in rats which had received either a single or a series of 10 electroconvulsive shock, compared to those which received sham treatment. In homogenates of the limbic forebrain, stimulation by both 100 microM dopamine and by 4 microM SKF 38393 was significantly increased after chronic electroconvulsive shock. The activity of D2 receptors, as measured by inhibition of forskolin-stimulated adenylate cyclase, in the presence of the D1 receptor antagonist SCH 23390, was unaltered by chronic electroconvulsive shock in either area of the brain. The selective effect of chronic electroconvulsive shock in increasing the activity of D1 receptors may account both for the increase, in dopamine-mediated behaviour, seen after chronic electroconvulsive shock and for the antiparkinsonian effects of this treatment.

Treatment of dopaminomimetic psychosis in Parkinson's disease with electroconvulsive therapy

Two Parkinsonian patients with chronic nonconfusional dopaminomimetic psychosis were treated with a course of electroconvulsive therapy. In both cases sustained remission of psychosis was obtained in the face of ongoing administration of dopaminomimetics.

On the mechanism of potentiation of apomorphine-induced stereotypy due to electroconvulsive shock

Electroconvulsive shock-induced changes in the intensity of stereotype induced by apomorphine, the binding of [3H]spiroperidol in the corpus striatum, the accumulation of [3H]dopamine in brain and the permeability of the blood-brain barrier, were monitored in rats 30 min after single, or 24 hr after chronic (once daily for 7 days) electroconvulsive shock. There was significant potentiation in stereotypy induced by apomorphine after chronic electroconvulsive shock. The binding of [3H]spiroperidol did not show any change in the affinity (Kd) or density (Bmax) of receptors in the striatum after acute or chronic electroconvulsive shock. The accumulation of dopamine increased significantly in the hypothalamus after acute electroconvulsive shock and in the corpus striatum and hypothalamus after chronic electroconvulsive shock. A significant increase in the entry of sodium fluorescein into the hypothalamus occurred after acute electroconvulsive shock; it increased in all the regions of the brain after chronic electroconvulsive shock. Alteration in the blood-brain barrier (BBB) by electroconvulsive shock leading to increased accumulation of dopamine in the corpus striatum may be responsible for the potentiation of stereotypy.

Attenuation by electroshock treatment of the haloperidol-induced rise in the binding of 3H-imipramine to rat brain membranes

Studies were conducted in rats to investigate whether chronic haloperidol treatment, electroshock treatment (EST), or a combination of both affects the high-affinity binding of 3H-imipramine to cerebral membranes. Chronic haloperidol (2 mg/kg SC daily for 28 days) resulted in a significant decrease in the density of binding sites in animals killed 1 h after the last treatment, but binding was markedly enhanced after a "washout" period of 5 days. In animals subjected to EST (20-30 mA, 1.5 s, 60 Hz; three times a week for 4 weeks) and killed 1 h after the last treatment, there were no apparent changes, but when animals were allowed a recovery period of 5 days there appeared to be a slight increase in binding. The marked increase in binding seen after haloperidol withdrawal was no longer apparent in animals treated with both haloperidol and EST, indicating that EST acts to attenuate the increase in binding seen after withdrawal of chronic haloperidol. It is suggested that chronic haloperidol may influence presynaptic recognition sites that regulate serotonin uptake and that EST may interact with haloperidol to "stabilize" these presynaptic sites.

Dopamine and serotonin metabolites in rat cerebroventricular fluid following withdrawal of haloperidol or electroshock treatment

Levels of the dopamine metabolites dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) and of the major serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) were determined in the CSF of rats at various times after repeated electroshock treatment (EST) or chronic administration of haloperidol. The acidic metabolites were analyzed in 25 microliter CSF using HPLC with an electrochemical detector. A significant decrease in the CSF levels of DOPAC and HVA was found 4 days after the last administration of chronic haloperidol, EST, or both. The decrease in the level of the dopamine metabolites indicated a slower dopamine turnover, which might have resulted from hypersensitivity of presynaptic dopamine receptors after these treatments. Rats treated with haloperidol also showed an increase in 5-HIAA levels, possibly due to enhanced serotonin turnover. The 5-HIAA increase following haloperidol was prevented by a concurrent administration of EST, suggesting attenuation by EST of the haloperidol-induced enhancement of serotonin turnover.

Electroconvulsive treatment and haloperidol: effects on pre- and postsynaptic dopamine receptors in rat brain

Electroconvulsive treatment (ECT) has a transitory beneficial effect on patients with Parkinson's disease (PD). The possibility that this effect is mediated by dopamine (DA) receptors was investigated in the rat brain. Repeated ECT or chronic haloperidol treatment induced supersensitivity of putative autoreceptors in the nigrostrital and mesolimbic DA pathways as reflected by enhanced apomorphine-induced inhibition of DA synthesis. Effect of simultaneous administration of ECT plus haloperidol on DA receptor sensitivity were not additive. Chronic haloperidol treatment induced significant elevations in the density of 3[H]-spiperone striatal binding sites. Concurrent administration of ECT had no effect on the neuroleptic-induced supersensitivity. ECT alone was also without effect on 3[H]-spiperone binding. Thus, ECT-induced increases in the sensitivity of presynaptic autoinhibition of DA release was not reflected by changes in the striatal 3[H]-spiperone binding sites. This suggests that effects of ECT on the DA system are not mediated by dopamine D2 receptors.

Clinical strategies for evaluating ECT mechanisms--pharmacological, biochemical and psychophysiological approaches

Although ECT is a highly effective treatment for severe depression and other psychiatric syndromes, its mode of action is not known. Recent studies have suggested that effects of ECT on central neurotransmitter receptors may underlie its therapeutic action. The effects of chronically administered electroconvulsive shock on receptors for dopamine, serotonin, noradrenaline, acetylcholine and endorphins in rodent brain, are reviewed. Strategies for evaluating the relevance of these animal findings to mechanisms of action of ECT in humans are discussed.

Chronic antidepressant therapy and associated changes in central monoaminergic receptor functioning

Acutely administered antidepressants possess a multiplicity of pharmacological actions. However, the fact that agents possessing similar pharmacological actions are devoid of antidepressant activity, together with the lack of correlation between doses required for acute pharmacological effects and clinical efficacy, suggest that the mechanism(s) of action of antidepressants cannot be directly attributed to the acute pharmacological properties of the drugs. The lag phase in onset of clinical effectiveness emphasizes the importance of adaptive changes following chronic antidepressant administration. A rapidly accelerating trend in attempting to delineate the precise molecular mechanisms of action of antidepressants is the shift in emphasis following chronic antidepressant therapies from alterations in uptake, storage, synthesis and release of neurotransmitters to adaptive changes in receptor functioning. These adaptations occur both pre- and postsynaptically. Examples of the former are alpha 2 and DA presynaptic receptors, both being down-regulated by certain forms of chronic antidepressant therapy. The fact that the NE-coupled adenylate cyclase system in rat brain slices is down-regulated by tricyclics, atypical antidepressants, MAO inhibitors and ECT emphasizes the importance of the system. Electrophysiological and behavioral studies point to the up-regulation of central alpha 1 and 5-HT receptor functioning following long-term antidepressant therapy. In contrast to the beta-adrenoceptor, these findings cannot be correlated with data from radioligand binding studies. In general central alpha 1-adrenoceptor binding remains unaltered. This is also true for 5-HT1 binding whereas cortical 5-HT2 binding is both increased and decreased depending on the type of antidepressant therapy being investigated. The relationship of these adaptive changes to the clinical efficacy of antidepressants in man is not clear since there is generally a lack of good models for studying human central receptor functioning. A review of current data from animal studies would tend to disfavour the view that all forms of antidepressant therapy possess a common mechanism of action. Perhaps multiple intervention sites exist. The introduction and evaluation of agents possessing a specificity of pharmacological action will undoubtedly aid psychotherapeutic research. The knowledge that peptides and 'classical' neurotransmitters can co-exist in the same neurone will undoubtedly generate studies of the significance and importance of the co-transmitter function of peptides in the mechanisms of action of antidepressant therapies.