Decreased Creatine Kinase Activity Caused by Electroconvulsive Shock

Chronic treatment with coenzyme Q10 reverses restraint stress-induced anhedonia and enhances brain mitochondrial respiratory chain and creatine kinase activities in rats

Several recent studies suggest a close link between mitochondrial dysfunction and depression. Coenzyme Q10 (CoQ10) is a mobile electron carrier in the mitochondrial respiratory chain (MRC) with antioxidant and potential neuroprotective activities. This study investigated the effect of chronic administration of CoQ10 (50, 100, and 200 mg/kg/day, intraperitoneally, for 4 weeks) on anhedonia and on the activities of MRC complexes and creatine kinase in the frontal cortex and hippocampus of Wistar rats subjected to chronic restraint stress (CRS, 6 h × 28 days). Exposure to CRS-induced anhedonic-like behavior (decreased sucrose preference), reduced body weight gain and food intake, increased adrenal gland weight, and altered the activity of the MRC complexes in the brain areas tested. CoQ10 dose-dependently antagonized CRS-induced depressive behavior by increasing sucrose preference (reversal of anhedonia), body weight, and food intake and reducing adrenal gland weight. CoQ10 also enhanced the activities of MRC complexes (I-IV) and creatine kinase in the frontal cortex and hippocampus. Thus, the reversal of CRS-induced anhedonia may be partially mediated by amelioration of brain mitochondrial function. The findings also support the hypothesis that brain energy impairment is involved in the pathophysiology of depression and enhancing mitochondrial function could provide an opportunity for development of a potentially more efficient drug therapy for depression.

Effects of maintenance electroshock on mitochondrial respiratory chain and creatine kinase activities in the rat brain

Réus GZ, Stringari RB, Rezin GT, Pezente DP, Scaini G, Maggi DD, De-Nês BT, Streck EL, Quevedo J, Feier G. Effects of maintenance electroshock on mitochondrial respiratory chain and creatine kinase activities in the rat brain.

Objective:Electroconvulsive therapy is used efficacious treatment for a variety of complicated psychiatric disorders and evidences have indicated that energy metabolism impairment may be involved in pathophysiology and treatment of mood disorders. This work was performed to determine creatine kinase and mitochondrial respiratory chain activities at different times after the maintenance electroconvulsive shock (ECS).

Methods:Male Wistar rats received a protocol mimicking therapeutic of maintenance or simulated ECS (sham) and were subsequently sacrificed immediately after, 48 h and 7 days after the last maintenance ECS. We measured creatine kinase and mitochondrial respiratory chain activities in the prefrontal cortex, hippocampus, cortex, cerebellum and striatum.

Results:Our results showed that maintenance ECS alter respiratory chain complexes and creatine kinase activities in the rat brain, but these effects were related to brain area and time after the ECS, in which the animal were killed.

Conclusion:Finally, these findings further support the hypothesis that alteration on the energy metabolism could be involved in the therapeutic or adverse effects of ECS.

Differential effects of escitalopram administration on metabolic parameters of cortical and subcortical brain regions of Wistar rats

OBJECTIVE

Considering that mitochondria may be drug targets and some characteristics of drug-mitochondria interactions may still be misjudged because of the difficulty in foreseeing and understanding all possible implications of the complex pathophysiology of mitochondria, our study aimed to investigate the effect of escitalopram on the activity of enzymes of mitochondrial energy metabolism.

METHODS

Animals received daily administration of escitalopram dissolved in saline [10 mg/kg, intraperitoneal (IP)] at 1.0 ml/kg volume for 14 days. Control rats received an equivalent volume of saline, 1.0 ml/kg (IP), for the same treatment period. Twelve hours after last injection, rats were killed by decapitation and brain areas were rapidly isolated. The samples were homogenised and the activities of mitochondrial respiratory chain complexes, some enzymes of Krebs cycle (citrate synthase, malate dehydrogenase and succinate dehydrogenase) and creatine kinase were measured.

RESULTS

We verified that chronic administration of escitalopram decreased the activities of complexes I and II-III in cerebellum, hippocampus, striatum and posterior cortex whereas prefrontal cortex was not affected. Complex II activity was decreased only in striatum without affecting prefrontal cortex, hippocampus, cerebellum and posterior cortex. However, chronic administration of escitalopram did not affect complex IV and enzymes of Krebs cycle activities as well as creatine kinase.

CONCLUSION

In this study we showed a decrease in the activities of complexes I and II-III in most of the brain structures analysed and complex II activity was decreased only in striatum. However, it remains to be determined if mitochondrial dysfunction is rather a causal or a consequential event of abnormal signalling.

Creatine metabolism and psychiatric disorders: Does creatine supplementation have therapeutic value?

Athletes, body builders, and military personnel use dietary creatine as an ergogenic aid to boost physical performance in sports involving short bursts of high-intensity muscle activity. Lesser known is the essential role creatine, a natural regulator of energy homeostasis, plays in brain function and development. Creatine supplementation has shown promise as a safe, effective, and tolerable adjunct to medication for the treatment of brain-related disorders linked with dysfunctional energy metabolism, such as Huntington's Disease and Parkinson's Disease. Impairments in creatine metabolism have also been implicated in the pathogenesis of psychiatric disorders, leaving clinicians, researchers and patients alike wondering if dietary creatine has therapeutic value for treating mental illness. The present review summarizes the neurobiology of the creatine-phosphocreatine circuit and its relation to psychological stress, schizophrenia, mood and anxiety disorders. While present knowledge of the role of creatine in cognitive and emotional processing is in its infancy, further research on this endogenous metabolite has the potential to advance our understanding of the biological bases of psychopathology and improve current therapeutic strategies.

Brain energy metabolism is increased by chronic administration of bupropion

OBJECTIVES

Based on the hypothesis that energy impairment may be involved in the pathophysiology of depression, we evaluated the activities of citrate synthase, malate dehydrogenase, succinate dehydrogenase (SDH), mitochondrial respiratory chain complexes I, II, II-III, IV and creatine kinase (CK) in the brain of rats submitted to chronic administration of bupropion.

METHODS

Animals received daily administration of bupropion dissolved in saline (10 mg/kg, intraperitoneal) at 1.0 ml/kg body weight. The rats received injections once a day for 14 days; control rats received an equivalent volume of saline. Twelve hours after the last administration, the rats were killed by decapitation and brain was rapidly removed and kept on an ice plate. The activities of the enzymes were measured in different brain areas.

RESULTS

We observed that the activities of citrate synthase and malate dehydrogenase, mithocondrial respiratory chain complexes I, II-III and IV and CK were not altered after chronic administration of bupropion. However, SDH activity was increased in the prefrontal cortex and cerebellum. In the hippocampus, cerebellum and striatum the activity of complex II was increased after chronic administration of bupropion.

CONCLUSIONS

Our results demonstrated that bupropion increased some enzymes of brain energy metabolism. These findings are in accordance with other studies which showed that some antidepressants may improve energy metabolism. The present results reinforce the hypothesis that antidepressants modulate brain energy metabolism.

Sex-specific antidepressant effects of dietary creatine with and without sub-acute fluoxetine in rats

The potential role of metabolic impairments in the pathophysiology of depression is motivating researchers to evaluate the treatment efficacy of creatine, a naturally occurring energetic and neuroprotective compound found in brain and muscle tissues. Growing evidence is demonstrating the benefit of oral creatine supplements for reducing depressive symptoms in humans and animals. A novel question is whether dietary creatine, when combined with antidepressant drug therapy, would be more effective than either compound alone. To answer this question, four studies were conducted to investigate the behavioral effects of combined creatine and low-dose fluoxetine treatment using the forced swim test in male and female rats. Sprague-Dawley rats were fed powdered rodent chow supplemented with 0%, 2% or 4% w/w creatine monohydrate for 5 weeks. Rats were injected with fluoxetine (5.0 or 10.0 mg/kg) or saline according to a sub-acute dosing schedule. Female rats maintained on a 4% creatine diet displayed antidepressant-like effects compared to non-supplemented females prior to fluoxetine treatment. In contrast, creatine did not alter behavior reliably in males. Following drug treatment and a second forced swim trial, the antidepressant-like profile of creatine remained significant only in females co-administered 5.0 mg/kg fluoxetine. Moreover, in females only, supplementation with 4% creatine produced a more robust antidepressant-like behavioral profile compared to either dose of fluoxetine alone. Estrous cycle data indicated that ovarian hormones influenced the antidepressant-like effects of creatine. Addressing the issue of sex differences in response to treatment may affect our understanding of creatine, its relationship with depressive behavior, and may lead to sex-specific therapeutic strategies.

Activity of mitochondrial respiratory chain is increased by chronic administration of antidepressants

OBJECTIVE

Depressive disorders, including major depression, are serious and disabling for affected patients. Although the neurobiological understanding of major depressive disorder focuses mainly on the monoamine hypothesis, the exact pathophysiology of depression is not fully understood.

METHODS

Animals received daily intra-peritoneal injections of paroxetine (10 mg/kg), nortriptyline (15 mg/kg) or venlafaxine (10 mg/kg) in 1.0 ml/kg volume for 15 days. Twelve hours after the last injection, the rats were killed by decapitation, where the brain was removed and homogenised. The activities of mitochondrial respiratory chain complexes in different brain structures were measured.

RESULTS

We first verified that chronic administration of paroxetine increased complex I activity in prefrontal cortex, hippocampus, striatum and cerebral cortex. In addition, complex II activity was increased by the same drug in hippocampus, striatum and cerebral cortex and complex IV activity in prefrontal cortex. Furthermore, chronic administration of nortriptyline increased complex II activity in hippocampus and striatum and complex IV activity in prefrontal cortex, striatum and cerebral cortex. Finally, chronic administration of venlafaxine increased complex II activity in hippocampus, striatum and cerebral cortex and complex IV activity in prefrontal cortex.

CONCLUSION

On the basis of the present findings, it is tempting to speculate that an increase in brain energy metabolism by the antidepressant paroxetine, nortriptyline and venlafaxine could play a role in the mechanism of action of these drugs. These data corroborate with other studies suggesting that some antidepressants modulate brain energy metabolism.

Effect of acute administration of ketamine and imipramine on creatine kinase activity in the brain of rats

OBJECTIVE

Clinical findings suggest that ketamine may be used for the treatment of major depression. The present study aimed to compare behavioral effects and brain Creatine kinase activity in specific brain regions after administration of ketamine and imipramine in rats.

METHOD

Rats were acutely given ketamine or imipramine and antidepressant-like activity was assessed by the forced swimming test; Creatine kinase activity was measured in different regions of the brain.

RESULTS

The results showed that ketamine (10 and 15mg/kg) and imipramine (20 and 30mg/kg) reduced immobility time when compared to saline group. We also observed that ketamine (10 and 15mg/kg) and imipramine (20 and 30mg/kg) increased Creatine kinase activity in striatum and cerebral cortex. Ketamine at the highest dose (15mg/kg) and imipramine (20 and 30mg/kg) increased Creatine kinase activity in cerebellum and prefrontal cortex. On the other hand, hippocampus was not affected.

CONCLUSION

Considering that metabolism impairment is probably involved in the pathophysiology of depressive disorders, the modulation of energy metabolism (like increase in Creatine kinase activity) by antidepressants could be an important mechanism of action of these drugs.

Brain creatine kinase activity is increased by chronic administration of paroxetine

Major depression is a serious and recurrent disorder often manifested with symptoms at the psychological, behavioral, and physiological levels. In addition, several works also suggest brain metabolism impairment as a mechanism underlying depression. Creatine kinase (CK) plays a central role in the metabolism of high-energy consuming tissues such as brain, where it functions as an effective buffering system of cellular ATP levels. Considering that CK plays an important role in brain energy homeostasis and that some antidepressants may modulate energy metabolism, we decided to investigate CK activity from rat brain after chronic administration of paroxetine (selective serotonin reuptake inhibitor), nortriptiline (tricyclic antidepressant) and venlafaxine (selective serotonin-norepinephrine reuptake inhibitor). Adult male Wistar rats received daily injections of paroxetine (10 mg/kg), nortriptiline (15 mg/kg), venlafaxine (10 mg/kg) or saline in 1.0 mL/kg volume for 15 days. Twelve hours after the last administration, the rats were killed by decapitation, the hippocampus, striatum and prefrontal cortex were immediately removed, and activity of CK was measured. Our results demonstrated that chronic administration of paroxetine increased CK activity in the prefrontal cortex, hippocampus and striatum of adult rats. On the other hand, nortriptiline and venlafaxine chronic administration did not affect CK activity in these brain areas. In order to verify whether the effect of paroxetine on CK is direct or indirect, we also measured the in vitro effect of this drug on the activity of the enzyme. We verified that paroxetine did not affect CK activity in vitro. Considering that metabolism impairment is probably involved in the pathophysiology of depressive disorders, an increase in CK activity by antidepressants may be an important mechanism of action of these drugs.

Effects of the HIV treatment drugs nevirapine and efavirenz on brain creatine kinase activity

Nevirapine (NVP) and efavirenz (EFV) are antiretroviral drugs belonging to potent class of non-nucleoside reverse transcriptase inhibitors (NNRTIs) widely used for the treatment human immunodeficiency virus (HIV) infection. It has been demonstrated that NVP and EFV are able to cross the blood-brain barrier and arrive at the central nervous system (CNS), causing important adverse effects related to their presence within this tissue. Considering that the exact mechanisms responsible for CNS toxicity associated with NVP and EFV remain unknown and that creatine kinase (CK) plays an important role in cell energy homeostasis, in the present work we evaluated CK activity in brain of mice after chronic administration of these drugs. Our results demonstrated that NVP and EFV significantly inhibited CK activity in cerebellum, hippocampus, striatum and cortex of mice. Although it is difficult to extrapolate our findings to the human condition, the inhibition of brain CK activity by NVP and EFV may be associated with neurological adverse symptoms of these drugs.

Mitochondrial dysfunction and psychiatric disorders

Mitochondrial oxidative phosphorylation is the major ATP-producing pathway, which supplies more than 95% of the total energy requirement in the cells. Damage to the mitochondrial electron transport chain has been suggested to be an important factor in the pathogenesis of a range of psychiatric disorders. Tissues with high energy demands, such as the brain, contain a large number of mitochondria, being therefore more susceptible to reduction of the aerobic metabolism. Mitochondrial dysfunction results from alterations in biochemical cascade and the damage to the mitochondrial electron transport chain has been suggested to be an important factor in the pathogenesis of a range of neuropsychiatric disorders, such as bipolar disorder, depression and schizophrenia. Bipolar disorder is a prevalent psychiatric disorder characterized by alternating episodes of mania and depression. Recent studies have demonstrated that important enzymes involved in brain energy are altered in bipolar disorder patients and after amphetamine administration, an animal model of mania. Depressive disorders, including major depression, are serious and disabling. However, the exact pathophysiology of depression is not clearly understood. Several works have demonstrated that metabolism is impaired in some animal models of depression, induced by chronic stress, especially the activities of the complexes of mitochondrial respiratory chain. Schizophrenia is a devastating mental disorder characterized by disturbed thoughts and perception, alongside cognitive and emotional decline associated with a severe reduction in occupational and social functioning, and in coping abilities. Alterations of mitochondrial oxidative phosphorylation in schizophrenia have been reported in several brain regions and also in platelets. Abnormal mitochondrial morphology, size and density have all been reported in the brains of schizophrenic individuals. Considering that several studies link energy impairment to neuronal death, neurodegeneration and disease, this review article discusses energy impairment as a mechanism underlying the pathophysiology of some psychiatric disorders, like bipolar disorder, depression and schizophrenia.

Methylphenidate increases creatine kinase activity in the brain of young and adult rats

AIMS

The high prevalence of Attention Deficit/Hyperactivity Disorder (ADHD) and the increased therapeutic use of methylphenidate (MPH) raise some concerns regarding its long-term side effects and safety profile. Considering that MPH effects on brain metabolism are poorly known and that creatine kinase (CK) plays an important role in cell energy homeostasis, we evaluated CK activity in the brain of young and adult rats following acute (one injection) or chronic (28 days) administration of MPH.

MAIN METHODS

MPH was acutely or chronically administered to young and adult rats. For acute administration, a single injection of MPH was given to rats on postnatal day (PD) 25 or PD 60, in the young and adult groups, respectively. For chronic administration, MPH injections were given to young rats starting at PD 25 once daily for 28 days (last injection at PD 53). In adult rats, the same regimen was performed starting at PD 60 (last injection at PD 88). CK activity was measured in brain homogenates.

KEY FINDINGS

Our results showed that MPH acute administration increased the enzyme in prefrontal cortex, hippocampus, striatum and cerebral cortex, but not cerebellum of young and adult rats. Chronic administration of MPH also increased CK activity in these brain regions, as well as the cerebellum, in young and adult rats. The highest dose (10.0 mg/kg) presented more pronouncing effects.

SIGNIFICANCE

The present findings suggest that acute or chronic exposure to MPH increased CK activity, an enzyme involved in energy homeostasis, in the brain of young and adult rats.

Effect of Electroconvulsive Shock on Mitochondrial Respiratory Chain in Rat Brain

It is well described that impairment of energy production has been implicated in the pathogenesis of a number of diseases. Although several advances have occurred over the past 20 years concerning the use and administration of electroconvulsive therapy (ECT) to minimize its side effects, little progress has been made in understanding its mechanism of action. In this work, our aim was to measure the activities of mitochondrial respiratory chain complexes II and IV and succinate dehydrogenase from rat brain after acute and chronic electroconvulsive shock (ECS). Our results showed that mitochondrial respiratory chain enzymes activities were increased after acute ECS in hippocampus, striatum and cortex of rats. Besides, we also demonstrated that complex II activity was increased after chronic ECS in cortex, while hippocampus and striatum were not affected. Succinate dehydrogenase, however, was inhibited after chronic ECS in striatum, activated in cortex and not affected in hippocampus. Finally, complex IV was not affected by chronic ECS in hippocampus, striatum and cortex. Our findings demonstrated that brain metabolism is altered by ECS.

Modulation of creatine kinase activity by ruthenium complexes

Creatine kinase is a crucial enzyme for brain, heart and skeletal muscle energy homeostasis, and a decrease of its activity has been associated with cell death. Many biological properties have been attributed to ruthenium complexes. In this context, this work was performed in order to evaluate creatine kinase activity from rat brain, heart and skeletal muscle (quadriceps) after administration of ruthenium complexes, trans-[RuCl(2)(nic)(4)] (nic=3-pyridinecarboxylic acid) 180.7 micromol/kg (complex I), trans-[RuCl(2)(i-nic)(4)] (i-nic=4-pyridinecarboxylic acid) 13.6 micromol/kg (complex II), trans-[RuCl(2)(dinic)(4)] (dinic=3,5-pyridinedicarboxylic acid) 180.7 micromol/kg (complex III) and trans-[RuCl(2)(i-dinic)(4)] (i-dinic=3,4-pyridinedicarboxylic acid) 180.7 micromol/kg (complex IV). Our results showed that complex I caused inhibition of creatine kinase activity in hippocampus, striatum, cerebral cortex, heart and skeletal muscle. Besides, complex II did not affect the enzyme activity. complexes III and IV increased creatine kinase activity in hippocampus, striatum, cerebral cortex and heart, but not in skeletal muscle. Besides, none of the complexes in vitro altered creatine kinase activity, suggesting that enzymatic activity is indirectly affected by complexes I, III and IV. It is believed that diminution of creatine kinase in brain of rats caused by complex I may be related to results from other study reporting memory impairment caused by the same complex. Further research is necessary in order to elucidate the effects of ruthenium complexes in other important metabolic enzymes.