Panax ginseng Attenuates MK-801-Induced Stereotypy in Mice

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1 스트레스硏究 : 第 17 卷第 4 號 2009 원저 Panax ginseng Attenuates MK-801-Induced Stereotypy in Mice *Kohwang Medical Research Institute, Kyung Hee University, Seoul, Medicinal Crops Division, Ginseng and Medicinal Plants Research Institute Rural Development Administration, Eumseong, Korea Sung Wook Kang*, Su Kang Kim*, Young Ock Kim, Seon Woo Cha, Joo-Ho Chung* Schizophrenia is a mental disorder with lifetime prevalence on approximately 1% of the general population. After MK-801 (NMDA receptor antagonist) treatment, stereotyped behavior in mice is significantly increased, and therefore this is widely used as an animal model for the study of the pathophysiology of schizophrenia. Ginseng, the root of Panax ginseng, is known as a representative tonic for over 2,000 years in East countries such as China, Japan, and Korea. The objective of this study was to investigate the effect of ginseng on stereotyped behavior in MK-801-induced mice. We evaluated the stereotypy score in mice after single and repeated administration of MK-801 to examine acute and chronic responses. A total of 80 male mice were used for the acute and chronic session tests. Each session test was divided into 4 groups (10 mice/group), which were treated with saline (Control group), 400 mg/kg ginseng (Control+Ginseng group), 0.6 mg/kg MK-801 (MK801 group), and 0.6 mg/kg MK-801 and 400 mg/kg ginseng (MK801+Ginseng group), respectively. For the acute session test, mice were injected with a single dose of MK-801 (0.6 mg/kg, i.p). For the chronic session test, mice were daily injected with MK-801 for consecutive 7 days. Ginseng (400 mg/kg, p.o) was administered 30 min before the MK-801 treatment. The results showed that stereotypy score was increased in the MK801 group of both the acute and chronic session tests, compared with the Control group. Ginseng reduced the score of MK-induced stereotypy in the chronic session test, but not in the acute session test. The present results might be related to the long-term effect of ginseng in treating the symptoms of schizophrenia, including stereotyped behavior. (Korean J Str Res 2009;17: ) Key Words: Schizophrenia, Ginseng, MK-801, Stereotypy INTRODUCTION Schizophrenia is a major psychosis typically accompanying a Correspondence to: Joo-Ho Chung, Kohwang Medical Research Institute, Department of Pharmacology, School of Medicine, Kyung Hee University, Hoegi-dong, Dongdaemun-gu, Seoul , Korea Tel: , jhchung@khu.ac.kr Received November 15, 2009, Revised November 20, 2009 Accepted December 5, 2009 marked thinking disturbance. Although it affects emotions, it is distinguished from mood disorders such as depression. It is characterized by clinical manifestations including positive symptoms responsible for hallucinations, delusion, and negative symptoms such as social withdrawal, difficulty in abstract thinking, and stereotyped thinking (Brown et al., 2005; Thaker, 2007). Developmental dysfunction of the hippocampal formation is thought to play a major role in the pathogenesis of schizophrenia (Berner, 2002; Maeda et al., 2007). Stereotyped behavior, hyperlocomotion, and social withdrawal produced by NMDA re- 435

2 스트레스硏究 : 제 17 권제 4 호 2009 ceptor blockers (Mastropaolo et al., 2004; Ma et al., 2009) are selectively suppressed by atypical antipsychotic clozapine but not by typical antipsychotic chlorpromazine (Kwon JS et al., 2005). Motor stereotypy, which is excessive and repetitive behaviors, can be induced with repeated or high doses of psychomotor stimulants and are features of some psychiatric disorders such as schizophrenia and obsessive compulsive disorder (Chartoff et al., 2001). MK-801 is an antagonist of the N-methyl-D-aspartate (NMDA) receptor, one of three known glutamate receptors. MK-801 has been used in creating an animal model for both positive and negative symptoms of schizophrenia (Rung et al., 2005; Dickerson et al., 2006). Antipsychotics are used for managing schizophrenia but some adverse effects can be developed. Therefore, patients open prefer herbal and alternative medicine (Edlinger et al., 2009). Ginseng, the root of Panax ginseng C.A. Meyer (Araliaceae), has been used as a representative tonic for over 2,000 years in Far East countries such as China, Japan, and Korea. Nowadays, ginseng is one of the most famous herbal medicines around the world (Nah SY et al., 2007; Dang et al., 2009). Although ginseng exhibits multiple pharmacological actions (Attele et al., 1999), the mechanisms of its various effects are still mostly unknown. Still, it has been reported that ginseng is promoted as an adaptogen and has anticarcinogenic and antioxidant properties (Davydov et al., 2000). In this study, we investigated the effects of ginseng on the symptoms of schizophrenia using a MK801-induced mice model. MATERIALS AND METHODS 1. Animals Male ICR mouse weighting g (Orient, Republic of Korea) were used. All animals were housed in standard cages at room temperature between 20 and 24 o C with a relative humidity of 55±5%, a 12 h light/dark cycle. Water and food were available ad libitum. All experimental procedures were approved by the Kyung Hee University Medical Center Institutional Animal Care and Use Committee, Seoul, Republic of Korea. 2. Treatments Dried roots of Panax ginseng were obtained from the National Institute of Crop Science and identified by Dr. Seong NS, Ginseng & Medicinal Crops Division, National Institute of Crop Science, Rural Development Administration (Suwon, Republic of Korea). Roots of Panax ginseng (1.0 kg) were extracted with 70% ethanol under sonication. The ethanol filtrate was evaporated in vacuum to give ethanol extracts (238 g), which were then stored at 20 o C until use. Powdered extracts were dissolved in saline to make a solution of 100 mg/ml. MK-801 (Sigma, St. Louis, MO, USA) was stored as a 4 mg/ml stock solution at 70 o C. Pre-dilution of stocks with saline to the final injection concentrations were stored at 4 o C. MK-801 (0.6 mg/kg) was intraperitoneally injected and ginseng (400 mg/kg) was administered per os at 30 min before MK-801 treatment. 3. Experimental designs We performed two session of experiments, acute and chronic sessions. Each session test was divided into 4 groups (10 mice/group), in which the mice were treated with saline (Control group), 400 mg/kg ginseng (Control+Ginseng group), 0.6 mg/kg MK-801 (MK801 group), and 0.6 mg/kg MK-801 and 400 mg/kg ginseng (MK801+Ginseng group), respectively. In the acute session test, mice were administered with a single injection of MK-801 (0.6 mg/kg, i.p). In the chronic session test, mice were daily injected with MK-801 for 7 consecutive days. 4. Behavioral observation The cage was a clear cubic arena and cm in size. A video tape recorder installed directly above the cage was used to record animals behavior. The behavior was recorded for 2 h and after the recording the behavior was analyzed in intervals of 20 min. Stereotypy score was measured following the methods described in previous reports (Huang et al., 1997; Zuo et al., 2007). Score 1; lying down, eyes closed (asleep). Score 2; lying down, eyes open (inactive). Score 3; normal grooming or chewing cage litter (in place activities). Score 4; moving about cage, sniffing, rearing (normal, alert, active). Score 5; running movement (hyperactive). Score 6; repetitive exploration of the cage at normal level of activity (slow patterned). Score 7; repetitive exploration of the cage with hyperactivity (fast patterned). Score 8; remaining in same place in cage with fast repetitive head and/or foreleg movement (restricted). Score 9; backing up, jumping, seizures, abnormally maintained postures, dyskinetic 436

3 Sung Wook Kang, et al:panax ginseng Attenuates MK-801-Induced Stereotypy in Mice Fig. 1. Effect of ginseng on stereoscopy by MK-801 single injection. Each group was used 10 mice. Control group, saline (i.p); Control+ Ginseng group, 400 mg/kg ginseng (p.o); MK801 group, 0.6 mg/kg MK-801 (i.p); MK801+Ginseng group, 0.6 mg/kg MK-801 (i.p) and 400 mg/kg ginseng (p.o). Values are means±sem. movements (dyskinetic-reactive). 5. Data analysis The results are expressed as the mean±standard error of the mean (S.E.M.). Effects of MK-801 were compared with saline controls using a repeated-measures analysis of variance (ANOVA) with Dunnett s post-hoc test. Results were considered to be statistically significant at p<0.05. RESULTS When the stereotypy score of all groups were compared, the MK-801-treated group showed a significantly higher score than the Control group until 120 min (Fig. 1, 2). When treated with MK-801, the mice showed a remarkable hyperactivity in compared to the other groups. In Fig. 1, the results of the acute session test are shown. At zero time, stereotypy scores of all groups were similar (Control, 2.75±0.25; Control+Ginseng, 2.50±0.29; MK801, 3.00±0.41, and MK801+Ginseng 2.75±0.750). At 20 min, the MK801 and MK801+Ginseng groups were 8.25±0.50 and 8.00±0.41. Until 120 min, the two groups showed a similar pattern. This indicates that ginseng didn t attenuate MK-801-induced stereotypy in the acute session test. In Fig. 2, the results of the chronic session test are shown. Fig. 2. Effect of ginseng on stereoscopy by MK-801 repeated injection for 7 days. Each group was used 10 mice. Control group, saline (i.p); Control+Ginseng group, 400 mg/kg ginseng (p.o); MK801 group, 0.6 mg/kg MK-801 (i.p); MK801+Ginseng group, 0.6 mg/kg MK-801 (i.p) and 400 mg/kg ginseng (p.o). Values are means±sem. *vs. Control group, p<0.05; vs. MK801 group, p<0.05. Ginseng treatment resulted in a significant decrease of stereotypy score in the chronic session test using repeated injection of MK-801. At zero time, stereotypy scores of all groups were similar (Control, 3.50±0.29; Control+Ginseng, 3.25±2.50; MK801, 3.50±0.29, and MK801+Ginseng, 3.75±0.25). At 20 min, the MK801+Ginseng group (7.00±0.41) showed a significantly decreased stereotypy score, compared to the MK801 group (8.25±0.48). Until 120 min, two groups showed a similar pattern again. The results indicate that ginseng treatment attenuated MK-801-induced stereotypy in the chronic session test, suggesting long-term effects of ginseng which may be helpful for the treatment of certain symptoms of schizophrenia. DISCUSSION Glutamate is one of the major neurotransmitter in the brain. Recently, in the pathogenesis of schizophrenia, the hypothesis of the hypofunction of NMDA receptors is getting importance. Pencycline and ketamine are noncompetitive antagonists of the NMDA receptor, and these drugs exacerbate cognitive dysfunction and psychotic state in schizophrenic patients. LY , an agonist of the metabotropic 2/3 glutamate, may help the treatment of schizophrenia (Paz et al., 2008; Bennett, 2009). Schizophrenic patients who have excitotoxic damage are expected 437

4 스트레스硏究 : 제 17 권제 4 호 2009 to pronounced negative symptoms such as cognitive deficits and profound psychosocial deterioration. Disinhibited glutamatergic activity could result from inhibition of NMDA receptor-mediated neurotransmission and a consequent failure to stimulate inhibitory GABAergic interneurons, and/or anatomic degeneration of inhibitory GABAergic interneurons (Deutsch et al., 2001). Stereotyped behaviors are thought to be competing motor activities that are mediated by distinct mechanisms (Segal et al., 1974). Systemic injection of a noncompetitive NMDA receptor antagonist MK-801 causes both increased locomotion and stereotyped behaviors in rodents. This has also been proposed to be a useful animal model for certain symptoms of schizophrenia (Wu et al., 2004). Stereotypy elicited by acute MK-801 administration to mice is a behavior that reflects the pharmacological creation of a state of NMDA receptor hypofunction (Zuo et al., 2009). However, pharmacological interventions that normalize the adverse effects of NMDA receptor antagonist have been evaluated as potential antischizophrenic therapies. We examined the effects of ginseng on the stereotyped behavior elicited by MK-801 treatment. Ginseng is widely used in the field of herbal medicine and it has served as an important component of many Chinese and Korean prescriptions since thousands of years. Today, it still occupies a permanent and prominent position in the herbal list (best-sellers) and is considered the most widely taken herbal product in the world (Radad et al., 2006). The relationships between the components of ginseng and NMDA receptor have been reported. One of ginsenosides, Rg3, could inhibit NMDA receptor, which may be for ginseng-mediated neuroprotective actions (Kim S et al., 2002). Gu et al.(2009) suggested that notoginsenoside R1 (NTR1) is the main active ingredient of Panax notoginseng may preferentially protect neurons from glutamate toxicity mediated by NMDA receptor in the brain. Also, 20(S)-ginsenoside Rh2 [20(S)-Rh2] was reported to possess preventive effect on NMDA receptor in cultured hippocampal neurons (Lee EY et al., 2006). These reports were studied about the function of the ginseng components as NMDA antagonist or inhibitor. However, a recent report has been investigated the opposite effect of ginseng against MK-801, a NMDA receptor antagonist (Qi et al., 2009). In this point of view, we focused on the effect of ginseng against NMDA antagonist. Our data show that Panax ginseng is effective on attenuating stereotypy induced by MK-801 treatment. Many patients with schizophrenia have serious problems with daily life, although symptoms are reduced by the prescription of antipsychotics. Still, antipsychotics have also various side effects on maintaining the treatment of schizophrenia (Gorwood, 2006). Therefore, it is important to reduce schizophrenic symptoms and/or side effects of antipsychotics. In summary, the present study provides evidence that administration of Panax ginseng attenuates MK801-induced stereotypy. It also suggests that Panax ginseng may help to ameliorate the stereotyped symptoms of schizophrenia. ACKNOWLEDGEMENTS We appreciate the financial support from Medicinal Crops Division, Ginseng and Medicinal Plants Research Institute Rural Development Administration ( ). REFERENCES Attele AS, Wu JA, Yuan CS (1999) Ginseng pharmacology: multiple constituents and multiple actions. Biochem. Pharmacol. 58: Berner P (2002) Conceptualization of vulnerability models for schizophrenia: historical aspects. Am. J. Med. Genet. 114: Bennett M (2009) Positive and negative symptoms in schizophrenia: the NMDA receptor hypofunction hypothesis, neuregulin/erbb4 and synapse regression. Aust. N. Z. J. Psychiatry 43: Brown AS, Bresnahan M, Susser ES (2005) Schizophrenia: environmental epidemiology. In: Sadock BJ. Sadock VA, eds. Comprehensive Textbook of Psychiatry. 8ed. P Lippincott. Williams and Wilkins, Baltimore. Md. Chartoff EH, Marck BT, Matsumoto AM et al. (2001) Induction of stereotypy in dopamine-deficient mice requires striatal D1 receptor activation. Proc. Natl. Acad. Sci. USA. 98: Dang H, Chen Y, Liu X et al. (2009) Antidepressant effects of ginseng total saponins in the forced swimming test and chronic mild stress models of depression. Prog. Neuropsychopharmacol. Biol. Psychiatry. 33: Davydov M, Krikorian AD (2000) Eleutherococcus senticosus (Rupr. & Maxim.) Maxim. (Araliaceae) as an adaptogen: a closer look. J. Ethnopharmacol. 72: Deutsch SI, Rosse RB, Schwartz BL et al. (2001) A revised excitotoxic hypothesis of schizophrenia: therapeutic implications. Clin. Neuro- 438

5 Sung Wook Kang, et al:panax ginseng Attenuates MK-801-Induced Stereotypy in Mice pharmacol. 24: Dickerson J, Sharp FR (2006) Atypical antipsychotics and a Src kinase inhibitor (PP1) prevent cortical injury produced by the psychomimetic, noncompetitive NMDA receptor antagonist MK Neuropsychopharmacology 31: Edlinger M, Hofer A, Rettenbacher MA et al. (2009) Factors influencing the choice of new generation antipsychotic medication in the treatment of patients with schizophrenia. Schizophr. Res. 113: Gorwood P (2006) Meeting everyday challenges: antipsychotic therapy in the real world. Eur. Neuropsychopharmacol. S3:S Gu B, Nakamichi N, Zhang WS et al. (2009) Possible protection by notoginsenoside R1 against glutamate neurotoxicity mediated by N-methyl-D-aspartate receptors composed of an NR1/NR2B subunit assembly. J. Neurosci. Res. 87: Huang NK, Wan FJ, Tseng CJ et al. (1997) Amphetamine induces hydroxyl radical formation in the striatum of rats. Life Sci. 61: Kim S, Ahn K, Oh TH et al. (2002) Inhibitory effect of ginsenosides on NMDA receptor-mediated signals in rat hippocampal neurons. Biochem. Biophys. Res. Commun. 296: Kwon JS, Kim KM, Chang SM et al. (2005). Differential effects of typical and atypical antipsychotics on MK-801-induced EEG changes in rats. Korean J. Physiol. Pharmacol. 9: Lee EY, Kim S, Chung KC (2006) 20(S)-ginsenoside Rh2, a newly identified active ingredient of ginseng, inhibits NMDA receptors in cultured rat hippocampal neurons. Eur. J. Pharmacol. 536: Ma J, Tai SK, Leung LS (2009) Ketamine-induced deficit of auditory gating in the hippocampus of rats is alleviated by medial septal inactivation and antipsychotic drugs. Psychopharmacology (Berl.) 206: Maeda K, Sugino H, Hirose T et al. (2007) Clozapine prevents a decrease in neurogenesis in mice repeatedly treated with phencyclidine. J. Pharmacol. Sci. 103: Mastropaolo J, Rosse RB, Deutsch SI (2004) Anabasine, a selective nicotinic acetylcholine receptor agonist, antagonizes MK-801-elicited mouse popping behavior, an animal model of schizophrenia. Behav. Brain Res. 153: Nah SY, Kim DH, Rhim H (2007) Ginsenosides: are any of them candidates for drugs acting on the central nervous system? CNS Drug. Rev. 13: Paz RD, Tardito S, Atzori M et al. (2008) Glutamatergic dysfunction in schizophrenia: from basic neuroscience to clinical psychopharmacology. Eur. Neuropsychopharmacol. 18: Qi Y, Zhu L, Wen Q et al. (2009) Ginsenoside Rg1 restores the impairment of learning induced by chronic morphine administration in rats. J. Psychopharmacol. 23: Radad K, Gille G, Liu L et al. (2006) Use of ginseng in medicine with emphasis on neurodegenerative disorders. J. Pharmacol. Sci. 100: Rung JP, Carlsson A, Rydén Markinhuhta K et al. (2005) (+)- MK-801 induced social withdrawal in rats; a model for negative symptoms of schizophrenia. Prog. Neuropsychopharmacol. Biol. Psychiatry. 29: Segal DS, Mandell AJ (1974) Long-term administration of d-amphetamine: progressive augmentation of motor activity and stereotypy. Pharmacol. Biochem. Behav. 2: Thaker GK (2007) Schizophrenia endophenotypes as treatment targets. Expert. Opin. Ther. Targets 11: Wu J, Zou H, Strong JA et al. (2005) Bimodal effects of MK-801 on locomotion and stereotypy in C57BL/6 mice. Psychopharmacology (Berl.) 177: Zuo DY, Cao Y, Zhang L et al. (2009) Effects of acute and chronic administration of MK-801 on c-fos protein expression in mice brain regions implicated in schizophrenia with or without clozapine. Prog. Neuropsychopharmacol. Biol. Psychiatry 33: Zuo DY, Wu YL, Yao WX et al. (2007) Effect of MK-801 and ketamine on hydroxyl radical generation in the posterior cingulate and retrosplenial cortex of free-moving mice, as determined by in vivo microdialysis. Pharmacol. Biochem. Behav. 86:

6 스트레스硏究 : 제 17 권제 4 호 2009 = 국문초록 = 정신분열병은정신병의일종으로전체인구에서약 1% 의발병률을가지고있다. 많은연구자가정신분열병의주요증상인인지장애및이상행동에관심을갖고연구하고있다. 인삼은아시아그중에서도한국, 일본, 중국에서약 2,000 년동안건강증진을위하여사용된약물이다. 이논문의실험목적은 MK801 로정신분열병과유사한증상을야기한동물모델에서인삼의효과를보고자하였으며, 급성과만성정신분열병유사동물모델을이용하여동물행동에어떤변화가있는지를관찰하였다. 급성모델은 MK-801 (NMDA receptor antagonist) 을 0.6 mg/kg (i.p) 농도로한번주사를놓았고, 만성모델은 7 일동안주사한후행동실험을비교관찰하였다. 인삼 (400 mg/kg) 은경구투여로 MK-801 투여 30 분전에투여하였다. MK-801 투여로야기된 stereotyped score 가급성과만성모델에서모두증가하였다. 인삼투여로는급성모델에서반복행동의완화에는유의성이나타나지않았지만, 만성모델에서는유의성을보였다. 이러한실험결과는인삼을장기간사용하였을때, 반복행동같은정신분열병의일부증상에효과를나타낼수있음을시사한다. 중심단어 : 정신분열병, 인삼, MK-801, 반복행동 440