Upregulation of GAD65 mRNA in the medulla of the rat model of metabolic syndrome

Metabolic syndrome is characterized by obesity, elevated blood pressure (BP), insulin resistance, and hypercholesterolemia. Recently an animal model of this disorder has been proposed in rats selectively bred based on their performance on a treadmill-running task. Accordingly, low capacity runner (LCR) rats exhibited all of the diagnostic criteria for metabolic syndrome, including elevated BP, as compared to their high capacity runner (HCR) counterparts [U. Wisløff, S.M. Najjar, O. Ellingsen, P.M. Haram, S. Swoap, Q. Al-Share, M. Fernstrom, K. Rezaei, S.J. Lee, L.G. Koch, S.L. Britton, Cardiovascular risk factors emerge after artificial selection for low aerobic capacity, Science 307 (2005) 418–420]. Previous studies have highlighted the importance of GABAergic neurotransmission in the medullary cardiovascular-regulatory areas in the central control of BP. Thus, we hypothesized a dysregulation in GABAergic transmission in the medullary cardiovascular-regulatory nuclei of LCR rats. To begin testing this hypothesis we carried out experiments examining expression of the GABA synthetic enzymes, GAD65 and GAD67, mRNAs in the two rat strains via radioactive in situ hybridization. Our results showed GAD65 and GAD67 mRNAs were widely expressed throughout the brainstem; quantification revealed increased GAD65 mRNA expression in LCR animals in the caudal nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (VLM) as compared to HCR rats. Conversely, no differences in the expression of GAD67 were detected in these regions. These data are consistent with the notion of altered GABAergic neurotransmission in the NTS and VLM in metabolic syndrome, and point to the importance of these regions in cardiovascular regulation.     

Differential role of GABAA and GABAB receptors in two distinct output stations of the rat striatum: studies on the substantia nigra pars reticulata and the globus pallidus

The role of GABA_A and GABA_B receptors in the substantia nigra pars reticulata and the globus pallidus in turning behaviour of rats was studied. Unilateral injection of the GABA_A receptor agonist muscimol (25 and 50 ng) into the substantia nigra pars reticulata elicited contralateral pivoting, namely tight head-to-tail turning marked by abnormal hindlimb backward stepping. This effect was GABA_A receptor specific, since it was dose-dependent and prevented by co-administration of the GABA_A receptor antagonist bicuculline (100 and 200 ng) which alone did not elicit turning behaviour. Unilateral injection of the GABA_B receptor agonist baclofen (100 and 200 ng) into the substantia nigra pars reticulata also produced contralateral pivoting. This effect was GABA_B receptor specific, since it was dose-dependent and inhibited by the GABA_B receptor antagonist CGP 55845 (200 ng) which alone did not elicit turning behaviour. In contrast, unilateral injection of bicuculline (100 and 200 ng) into the globus pallidus produced contralateral circling, namely turning marked by normal stepping. This effect was GABA_A receptor specific, since it was dose-dependent and prevented by muscimol (50 ng), which alone did not elicit turning behaviour. Unilateral injection of baclofen (100 and 200 ng) into the globus pallidus dose-dependently produced ipsilateral pivoting; this effect was inhibited by CGP 55845 (200 ng), which alone did not elicit turning behaviour. The present study demonstrates that GABA_A and GABA_B receptors in the globus pallidus and the substantina nigra pars reticulata play differential roles in the production of turning behaviour. This study underlines the notion that the two types of turning, namely pivoting and circling, are valid tools to map out the information flow across the basal ganglia.     

细胞外信号调节激酶在三叉神经痛动物模型中的表达

为了研究细胞外信号调节激酶(ERK)信号转导通路在三叉神经痛动物模型中的表达,将24只雄性SD大鼠分为三叉神经痛模型组和对照组两组,模型组大鼠以铬制羊肠线疏松结扎大鼠一侧眶下神经,对照组大鼠眶下神经不结扎。应用免疫组化和免疫荧光染色方法,分别检测大鼠三叉神经节(TG)和三叉神经脊束核尾侧亚核(Vc)中磷酸化ERK(p-ERK)的表达。本研究发现p-ERK在模型组和对照组大鼠的TG和Vc中均有不同程度的表达,但模型组大鼠中p-ERK表达明显高于对照组(P<0.05)。提示ERK可能参与了三叉神经痛(TGN)痛觉信号的传导,在三叉神经痛的发病机制中发挥重要的作用。     

Fluoroscopic Caudal Epidural Injections in Managing Post Lumbar Surgery Syndrome: Two-Year Results of a Randomized,Double-Blind,Active-Control Trial

Study Design: A randomized, active control, double-blind trial. Objective: To evaluate the effectiveness of fluoroscopically directed caudal epidural injections with or without steroids in managing chronic low back and lower extremity pain secondary to post lumbar surgery syndrome. Summary of Background Data: There is a paucity of evidence concerning caudal epidural injections for managing chronic persistent low back pain with or without lower extremity pain caused by post lumbar surgery syndrome.Methods: This active control randomized study included 140 patients with 70 patients in each group. Group I received 0.5% lidocaine, 10 mL; Group II received 9 mL of 0.5% lidocaine mixed with 1 mL of 6 mg of nonparticulate betamethasone. The multiple outcome measures included the numeric rating scale, the Oswestry Disability Index 2.0, employment status, and opioid intake with assessments at 3, 6, 12, 18, and 24 months posttreatment. Primary outcome was defined as at least 50% improvement in pain and Oswestry Disability Index scores. Patients with a positive response to the first 2 procedures with at least 3 weeks of relief were considered to be successful. All others were considered as failures.Results: Overall in Group I, 53% and 47% of the patients and in Group II, 59% and 58% of the patients, showed significant improvement with reduction in pain scores and disability index at 12 months and 24 months. In contrast, in the successful groups, significant pain relief and improvement in function were observed in 70% and 62% of Group I at one and 2 years; in 75% and 69% of Group II at one and 2 years. The results in the successful group showed that at the end of the first year patients experienced approximately 38 weeks of relief and at the end of 2 years Group I had 62 weeks and Group II had 68 weeks of relief. Overall total relief for 2 years was 48 weeks in Group I and 54 weeks in Group II. The average procedures in the successful groups were at 4 in one year and 6 at the end of 2 years.Conclusion: Caudal epidural injections of local anesthetic with or without steroid might be effective in patients with chronic persistent low back and/or lower extremity pain in patients with post lumbar surgery syndrome.     

The role of 5-HT receptor subtypes in the ventrolateral orbital cortex of 5-HT-induced antinociception in the rat

The present study examined the involvement of 5-HT in the ventrolateral orbital cortex (VLO) on descending antinociception and determined which subtypes of 5-HT receptors mediated this effect. This study focused on the effects of 5-HT microinjection in the VLO of lightly anesthetized male rats on the radiant heat-evoked tail flick (TF) reflex, as well as the influence of 5-HT(1A), 5-HT(2), 5-HT(3), and 5-HT(4) receptor subtype antagonists on the effect of 5-HT. Results showed that 5-HT microinjection (2, 5, 10 microg, in 0.5 microl) into the VLO depressed the TF reflex in a dose-dependent manner. Pretreatment with 5-HT receptor antagonists (1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), cyproheptadine hydrochloride (CPT) and 1-methyl-N-(8-methyl-8-azabicyclo[3.2.3]-oct-3-yl)-1H-indazole-3-carboxamide maleate salt (LY-278,584)), specific for 5-HT(1A), 5-HT(2) and 5-HT(3) receptors, respectively, partially reversed the 5-HT-evoked inhibition. In contrast, the 5-HT(4) receptor antagonist, 1-[2-[(methylsulfonyl)-amino]ethyl]-4-piperidinyl]methyl1-methyl-1H-indole-3-carboxylate (GR 113808), had no effect on the inhibition of 5-HT. Microinjections of NAN-190, CPT and LY-278,584 alone into the VLO had no effect on the TF reflex. These results suggest that 5-HT(1A), 5-HT(2) and 5-HT(3), but not 5-HT(4) receptors, are involved in mediating 5-HT-induced antinociception in the VLO. According to different properties and distribution patterns of the 5-HT receptor subtypes on neurons, the possible mechanism of 5-HT activation of the VLO-periaqueductal gray (PAG) descending antinociceptive pathway is discussed.     

Gestational diabetes mellitus (class A): A human teratogen?

Between January 1, 1982 and December 31, 1992 we evaluated 200 children of mothers with pregestational or gestational diabetes mellitus through the University of South Florida Genetics/Dysmorphology Clinics. They were a portion of the 22,100 families seen during that period. Pregnant women with diabetes mellitus were not part of this study. One hundred and fifty-two of the 200 were offspring of mothers with gestational diabetes (classes A₁ and A₂). Class B₁ was not encountered as a subclass of gestational diabetes in this series. Twenty-four of the 152 did not have anomalies. Forty-one of the 152 had another primary diagnosis to account for their malformations. Eighty-seven of the 152 had a constellation of anomalies or solitary structural defects as seen in diabetic embryopathy. Chromosomal, monogenic, and other teratogenic causes were excluded. The observed phenotypes matched those seen in offspring of mothers with diabetes mellitus classes B₂ to T. They also corroborated the animal studies, indicating that the embryopathy of gestational diabetes has a pathogenesis similar to that in classes B₂ to T, and recent epidemiological studies showing a statistically significant increase of anomalies as in diabetic embryopathy in the offspring of gestational diabetes mothers. As per established obstetric practice the testing for gestational diabetes was after gestation 16 weeks. Thus, it was impossible to prove that the anomalies of the 87 propositi were due to gestational diabetes. However, the anomalies occurred during organogenesis as in the other diabetic classes, and inferred that gestational diabetes is a human teratogen. If so, common “idiopathic” malformations may be actually caused by undiagnosed maternal gestational diabetes. Am. J. Med. Genet. 83:402–408, 1999. © 1999 Wiley-Liss, Inc.     

腹外侧眶皮层中miR-200对慢性应激所致大鼠抑郁行为调控作用研究

目的:观察慢性不可预知温和应激(CUMS)模型大鼠腹外侧眶皮层(VLO)内miR-200和双特异性磷酸酶1(DUSP1)表达变化,并探讨VLO内注射miR-200模拟物对抑郁行为的调控作用及机制。方法:大鼠建立CUMS抑郁模型后分为5组:CUMS+miR-200模拟物组(VLO内注射20 pmol miR-200 mimic);CUMS+阴性对照组(VLO内注射20 pmol阴性对照siRNA);无应激+阴性对照组;无应激+miR-200模拟物组;CUMS+氟西汀(10 mg/kg/d)组。依次进行蔗糖偏爱测试、旷场实验、高架十字迷宫实验。Western Blot检测VLO内DUSP1、细胞外调节蛋白激酶(ERK)、pERK蛋白表达。结果:与无应激组比较,CUMS组大鼠体重降低(P0.0001)、蔗糖偏爱下降(P=0.008),VLO中miR-200表达减少(P0.0001),DUSP1表达增高(P=0.0054);与CUMS+阴性对照组比较,CUMS+miR-200模拟物组大鼠蔗糖偏爱率(P=0.028),开放臂进入时间(P=0.031)和进入次数(P0.0001)均升高,总活动距离不受影响;与CUMS+阴性对照组比较,CUMS+miR-200模拟物组VLO中DUSP1(P=0.046)和pERK(P=0.042)蛋白水平显著升高。结论:慢性应激性环境所致抑郁样行为与VLO内pERK下调有关,miR-200可直接下调VLO内DUSP1表达,提高pERK表达并最终改善抑郁症状。     

Somatotopic arrangement and location of the corticospinal tract in the brainstem of the human brain

The corticospinal tract (CST) is the most important motor pathway in the human brain. Detailed knowledge of CST somatotopy is important in terms of rehabilitative management and invasive procedures for patients with brain injuries. In this study, I conducted a review of nine previous studies of the somatotopical location and arrangement at the brainstem in the human brain. The results of this review indicated that the hand and leg somatotopies of the CST are arranged medio-laterally in the mid to lateral portion of the cerebral peduncle, ventromedial-dorsolaterally in the pontine basis, and medio-laterally in the medullary pyramid. However, few diffusion tensor imaging (DTI) studies have been conducted on this topic, and only nine have been reported: midbrain (2 studies), pons (4 studies), and medulla (1 study). Therefore, further DTI studies should be conducted in order to expand the literature on this topic. In particular, research on midbrain and medulla should be encouraged.