Role of group mGluR in low dose ketamine protecting learning and memory function after electroconvulsive shock in depression rats / 上海交通大学学报（医学版）

Objective • To investigate the role of group I metabotropic glutamate receptor (mGluR) in the regulation of N-methyl-D-aspartic acid receptor (NMDAR)-mediated synaptic plasticity in low dose ketamine protecting learning and memory function after modified electroconvulsive shock (MECS). Methods • The 2-3-month-old Sprague Dawley (SD) rats were used to establish depression models with chronic unpredictable mild stress. Ten healthy rats were used as the control group (group C), and another 30 depressed rats were randomly divided into group D, group M, and group KM. Group C was not treated, group D was treated with pseudo-MECS after intraperitoneal injection of normal saline, group M was given intraperitoneal injection of propofol, and group KM was given intraperitoneal injection of propofol combined with low-dose ketamine (10 mg/kg). Both group M and group KM underwent MECS. The sucrose preference test was used to evaluate the depression status. The Morris water maze was used to detect the spatial learning and memory function. The expression of NMDAR1, mGluR1 and mGluR5 proteins in the hippocampus was detected by Western blotting. Another 36 depressed rats were randomly divided into 6 groups: group DE, group m1E, group m5E, group DE', group m1E', and group m5E'. Group DE and group DE' were perfused with artificial cerebrospinal fluid alone. Group m1E and group m1E' were perfused with artificial cerebrospinal fluid containing mGluR1 blocker. Group m5E and group m5E' were perfused with artificial cerebrospinal fluid containing mGluR5 blocker. Long-term potentiations (LTP) were detected in group DE, group m1E, and group m5E. NMDAR-mediated field potentials (fEPSPNMDAR) were detected in group DE', group m1E', and group m5E'. Results • After treatment, the sucrose preference percentages of group M and group KM increased compared with group D (P<0.05), the escape latencies (EL) of group M and group KM were prolonged (P<0.05), and the space exploration times (SET) were shortened (P<0.05). Compared with group M, the EL of group KM was shortened (P<0.05), and the SET was prolonged (P<0.05). Compared with group D, the expression levels of NMDAR1, mGluR1 and mGluR5 in group M and group KM decreased (P<0.05). Compared with group M, the expression levels of NMDAR1, mGluR1 and mGluR5 in group KM increased (P<0.05). Compared with group DE, the LTP decreased in group m1E and group m5E (P<0.05). Compared with group DE', the fEPSPNMDAR of group m1E' and group m5E' decreased (P<0.05). Conclusion • Ketamine up-regulates NMDAR1 and group mGluR expression to enhance the activation of NMDAR in the hippocampus which may be responsible for the protective effects on spatial learning and memory function in depression rats undergoing MECS.

Effects of ketamine combined with electroconvulsive shock on inflammation and amyloid-beta peptide in hippocampus of depressive rats / 局解手术学杂志

Objective To investigate the effects of ketamine combined with electroconvulsive shock (ECS) on inflammation and amyloid-beta peptide in hippocampus of depressive rats.Methods Chronic unpredictable mild stress (CUMS) was used to generate animal models of depression.Forty-eight adult male Sprague-Dawley rats were randomly divided into 4 groups (n=12):depression model group (group D),electroconvulsive shock group (group DE),ketamine combined with electroconvulsive shock group (group DKE),and ketamine group (group DK).Rats in group D received sham ECS treatment;rats in group DE received ECS treatment;rats in group DKE were given intraper-itoneal injection of ketamine (100 mg/kg) and then received ECS treatment;rats in group DK were given intraperitoneal injection of ketamine (100 mg/kg) and then received sham ECS treatment.Morris water maze was used to assess the memory abilities of rats.The expression levels of IL-1β and TNF-α were measured by real-time PCR.Enzyme-linked immunosorbent assays were used to detect the levels of soluble Aβ.Results Before the administration of ECS or ketamine treatment,there was no significant difference in the escape latencies and space exploration time between the 4 groups (P>0.05).After the ECS and ketamine treatment,rats of group DKE exhibited a shorter escape latencies and a longer space exploration time,and the expression of IL-1β and TNF-α mRNA were down-regulated while the concentration of Aβ1-40 and Aβ1-42 were increased compared with group DE with significant difference (P<0.05).Conclusion Ketamine can alleviate ECS-induced learning and memory impairments in depressive rats.This cognition-protecting effect of ketamine may be attributed to its suppression of ECS-induced neuroinflammation and decrease of the levels of soluble Aβ in the hippocampus of depressive rats.

Changes of AP-1 Binding Activities in Rat Brain by Electroconvulsive Shock / 신경정신의학

OBJECTIVES: ECS could have therapeutic effects on psychiatric illnesses by inducing IEGs, which in turn regulates expression of their target genes. We observed AP-1 binding activity and identified AP-1 binding proteins in NMDAR1, late response gene of IEGs, which considered as the candidate gene for schizophrenia. METHODS: By gel shift assay and supershift assay, we observed binding activities and AP-1 binding proteins in NMDAR1. Because IEGs are induced rapidly but transiently by external stimuli, there is a possibility that the expression of IEGs is negatively feedbacked by their own products via their AP-1 binding sites. For that purpose, we also observed AP-1 binding activity of c-fos and c-jun via gel shift and supershift assay. RESULTS: ECS increased AP-1 binding activities of NMDAR1 gene, contributed by c-Fos and its related proteins. Peak of the increased binding was 60 minutes in both hippocampus and cerebellum. Though expression of c-Fos and c-Jun were increased by ECS, there were no changes in AP-1 binding activities after ECS. AP-1 sites of IEGs were binded by CREB, regardless of ECS. CONCLUSION: There is a possibility that ECS induced IEG expression, and then incresed expression of NMDR1 by binding of expressed IEGs to the AP-1 site of NMDAR1. ECS did not increase AP-1 binding activities of IEGs. This suggests that the regulation of IEGs' expression can not be influenced mainly by AP-1 site.

The Effects of Repeated Electroconvulsive Shock on the Expression of NMDA Receptor Subunits in the Rat Hippocampus / 신경정신의학

OBJECTIVES: The N-methyl-D-aspartate (NMDA) receptor plays an important role in synaptic plasticity. The functional NMDA receptor is an oligomer of several subunits and the most abundant subunits in the brain are NR1, NR2A and NR2B. The function of the NMDA receptor is regulated by protein phosphorylation and by changes in the level of protein expression. The present study examined the effect of repeated electroconvulsive shock (ECS), an effective antidepressant and antipsychotic measure, on the expression of NMDA receptor subunit proteins in the rat hippocampus. METHODS: Male Sprague-Dawley rats were given 1, 5, or 10 consecutive daily ECS and the amounts of NR1, NR2A, and NR2B in the hippocampus were assessed by the immunoblot analysis. RESULTS: The expression levels of NR1 and NR2A subunits were found positively correlated with the number of treatment. However, there was no evidence of NR2B regulation by ECS. CONCLUSION: These findings suggest the action of ECS in the regulation of the NMDA receptor, and hence in the regulation of synaptic plasticity.

The Effects of Cyclosporin A on the Signal Transduction System in the Rat Brain / 대한정신약물학회지

The most important molecular mechanisms of intraneuronal signal transduction are those mediated by calcium and reversible protein phosphorylation. Although many studies pursued the activation of the protein kinases in the nervous system, there are only few reports focused on the protein phosphatases. In this article, the authors report the effects of cyclosporin A (CSA), an inhibitor of calcineurin, on the calcium signaling-related molecules such as ERKs, calmodulin-dependent kinase II (CaMKII) and CREB in the rat hippocampus. The authors also report the effects of cyclosporin A on the electroconvulsive shock (ECS)-induced seizure and the activation of ERKs. Calcineurin is a protein phosphatase that is abundant in the brain and regulated by calcium and calmodulin. It is proposed that calcineurin plays central roles in the synaptic plasticity and neuronal apoptosis. CSA (50 mg/kg) increased the phosphorylation of ERK, CaMKII and CREB. The treatment of of CSA increased the duration of tonic phase of seizure induced by ECS and augmented the phosphorylation of ERKs after ECS. These results suggested the protective role of calcineurin against the excessive electrical and molecular activities in the brain.

Differential changes in the expression of cyclic nucleotide phosphodiesterase isoforms in rat brains by chronic treatment with electroconvulsive shock

Electroconvulsive shock (ECS) has been suggested to affect cAMP signaling pathways to exert therapeutic effects. ECS was recently reported to increase the expression of PDE4 isoforms in rat brain, however, these studies were limited to PDE4 family in the cerebral cortex and hippocampus. Thus, for comprehensive understanding of how ECS regulates PDE activity, the present study was performed to determine whether chronic ECS treatment induces differential changes in the expression of all the PDE isoforms in rat brains. We analyzed the mRNA expression of PDE isoforms in the rat hippocampus and striatum using reverse transcription polymerase chain reaction. We found chronic ECS treatment induced differential changes in the expression of PDE isoform 1, 2, 3, 4, 5 and 7 at the rat hippocampus and striatum. In the hippocampus, the expression of PDE1A/B (694%), PDE4A (158%), PDE4B (323 %), and PDE4D (181%) isoforms was increased from the controls, but the expression of PDE2 (62.8%) and PDE7 (37.8%) decreased by chronic ECS treatment. In the striatum, the expression of PDE1A/B (179%), PDE4A (223%), PDE4B (171%), and PDE4D (327%) was increased by chronic ECS treatment with the concomitant decrease in the expression of PDE2 (78.4%) and PDE3A (67.1%). In conclusion, chronic ECS treatment induces differential changes in the expression of most PDE isoforms including PDE1, PDE2, PDE3, PDE4, PDE5, and PDE7 in the rat hippocampus and striatum in an isoform- and brain region-specific manner. Such differential change is suggested to play an important role in regulation of the activity of PDE and cAMP system by ECS.

A New Gene Regulated by Electroconvulsive Shock in Rat Brains / 신경정신의학

OBJECTIVES: This study was performed to identify genes regulated by electroconvulsive shock (ECS) and to observe the pattern of expression of genes according to different developmental stages and brain regions. METHODS: ECS(130V, 0.5 sec) was given to male Sprague-Dawley rats with age of postnatal day 7 and 21(P7, P21 respectively). After screening genes regulated by ECS with mRNA differential display-PCR(DD-PCR), we selected one clone among them and observed the induction of this gene after ECS by time-dependent Northern blot analysis of rat brain of P7, P21 and adult rat cortex and hippocampus. RESULTS: By DD-PCR method, we have identified four clones whose expression was regulated by ECS. Among them, one(CP 10-2) was proved to be a new gene by sequencing and BLAST search. Its expression was increased after ECS in P7, P21, and adult rat brain. The expression of CP 10-2 reached peak level at 180 minutes after ECS in P7 rat brain, but was further increased until 360 minutes after ECS in P21 and adult rat brain. CONCLUSION: In this study, a new gene was identified in rat brain which showed up-regulated expression in response to ECS. Cloning and characterization of this new gene would be helpful to elucidate the effect of ECS in rat brain.

Developmental Changes in the Phosphorylation of CREB Following Electroconvulsive Shock in Rat Brain / 신경정신의학

OBJECTIVES: In order to understand the biological basis of neurodevelopmental perspectives of mental disorders, the authors investigated the developmental and regional changes in the phosphorylation of the transcription factor CREB following the electroconvulsive shock(ECS) in rat brain. METHODS: Rats of various age groups (7, 14, 21 days postnatal and adults) were given ECS and their hippocampi and cerebella were dissected at specified time points. The content of CREB and phosphorylated CREB were measured by immunoblot analysis. RESULTS: The amount of CREB increased in the hippocampus and decreased in the cerebellum according to the age. Baseline levels of CREB phosphorylation in both tissues were increased from postnatal 14 days, and it was proportional to the amount of CREB protein in the cerebellum. In the hippocampus, ECS increased the phosphorylation of CREB at postnatal 21 days, but in the cerebellum, ECS did not increased the phosphorylation of CREB in any age group. CONCLUSION: CREB mediated signal transduction pathways showed developmental and tissue-specific changes. ECS increased the phosphorylation of CREB in the hippocampus by postnatal 21 days, but not in the cerebellum. CREB activation is supposed to be related with the inducdion of c-fos after ECS in the hippocampus. However, the Ser-133 phosphorylation of CREB could not completely explain the developmental and tissue specificity of c-fos induction.

The Effect of Electroconvulsive Shock on Chloramphenicol-Induced Insomnia in Freely-Moving Rats / 신경정신의학

OBJECTIVES: Muramyl peptide derived from bacterial cell wall has been identified as one of several endogenous sleep-promoting factors. Several studies have shown that the administration of antibiotics decreased sleep amount as well as bacterial colony numbers in rats. Electroconvulsive shock (ECS)has been widely used in the treatment of many psychiatric disorders, including depression, bipolar disorder, and some cases of schizophrenia. However exact mechanism of ECS on the normal or psychiatric condition is not well understood so far. Previous studies indicated that ECS has diverse effects on sleep parameters both in the human and animal subjects. However, there was no report to examine the relationship between effects of ECS and sleep in the antibiotic imposed animal subjects. Therefore the author studied the effects of ECS on chloramphenicol-induced insomnia in rats. METHODS: Twelve Sprague-Dawley strain rats were divided into control (N=6)and experimental group (N=6) The sleep-wake activity was recorded continuously for consecutive three days(baseline, day 1 and day 2) On day 1, both groups were intraperitoneally injected with chloramphenicol 150mg/kg. On day 2, the control group was intraperitoneally injected with chloramphenicol 150mg/kg only, whereas experimental group received ECS an hour after they were injected with chloramphenicol 150mg/kg. RESULTS: 1)Chloramphenicol administration decreased light period slow wave sleep (SWS) (t=4.944, p=0.000) and paradoxical sleep (PS) (t=3.887, p=0.003) as well as total SWS(t=2.98, p=0.012)and total PS (t=4.391, p=0.001) 2)ECS increased dark period SWS(t=-3.863, p=0.003)and dark period PS (t=-2.458, p=0.034)as well as total dark period sleep (t=-4.302, p=0.002) CONCLUSION: These results suggest that ECS may be effective to reverse chloramphenicolinduced insomnia in rats. Furthermore, chloramphenicol-induced insomnia in rats could be a useful animal model for the future sleep research.

Regulation of MAPK Activity by Seizure-induced MKP-1 in Rat Hippocampus / 신경정신의학

OBJECTIVES: Both electroconvulsive shock(ECS) and kainic acid-induced seizures activate mitogenactivated protein kinases(MAPKs)in rat hippocampus. They can also induce the expression of MAPK phosphatase-1(MKP-1)in rat hippocampus. MKP-1 is known as a specific MAPK deactivator. This study aimed to elucidate the role of MKP-1 in the deactivation of MAPKs in rat hippocampus. METHODS: In order to induce MKP-1 in the hippocampus, ECS was given to the rats. At the time points when MKP-1 was sufficiently induced, the second ECS was given to them and the subsequent phosphorylation or activation of MAPKs were measured in the hippocampus. A second group of rats were injected with kainic acid and the relationship between MKP-1 expression and MAPK phosphorylation was examined in their hippocampi. RESULTS: The expression of MKP-1 did not influence the phosphorylation or activation of MAPKs following ECS in rat hippocampus. Kainic acid-induced expression of MKP-1 did not significantly reduce the phosphorylation of MAPKs. CONCLUSION: MKP-1 did not play a significant role in the deactivation of MAPKs which were activated by ECS or kainic acid in rat hippocampus.

Stress Among Chinese, Korean-Chinese and Korean High School Students: A Transcultural Study / 신경정신의학

OBJECT: In order to examine the interaction mechanisms of electroconvulsive shock(ECS) and antipsychotic drug at the level of molecular biology, we observed the effect of chlorpromazine pre-treatment on the activation of mitogen activated protein kinase(MAPBD induced by electroconvulsive shock(ECS) in rat hippocampus. METHODS: Male Sprague-Dawley rats were divided into 2 groups. To the experimental group chlorpromazine(20mg/kg) was given intraperitoneally, 3nd to the control disliked water was given instead. Thirty minutes later, ECS was given and the hippocampus was dissected out 2 minutes thereafter. Immunoblotting with antiphosphotyrosine antibody was carried out, and the signal intensity at 42kDa band was quantitized using densitometer. The obtained result was compared by student t-test between the experimental and the control group. The absolute amount of MAPK was measured by immunoblotting with anti-MAPK antibody. RESULT: The tyrosine phosphorylation of MAPK reached peak at 2 minutes after ECS. However, in the chlorpromazine pre-treated group, the peak level of MAPK tyrosine phosphorylation was significantly attenuated(t= -3.12, df= 14, p=0.008) compared to the control. In contrast to this, the absolute amount of MAPK did not differ between the pretreated and the control group. CONCLUSION: Chlorpromazine attenuated the tyrosine phosphorylation of MAPK by ECS. This finding seems to be related to the fact that chlorpromazine pre-treatment changed the c-fos expression by ECS in rat brain. Antipsychotic drug and ECS might interact at the level of MAPK signal transduction system, and this might explained the observed synergistic elect of two treatment modality.