Effects of Ovariectomy and 17β-Estradiol Replacement on the Activity of Dopamine D2 Receptors in the Selection of Macronutrients Carbohydrates, Lipids and Proteins in Females Rats

17β-estradiol modulates the activity of D2 receptors in the regulation of food intake and body weight. The functional lack of 17β-estradiol in postmenopausal women could create a dietary imbalance and cause body weight gain. This study aimed to better understand the interferences that could exist between 17β-estradiol, D2 receptors and the selection of carbohydrate, fat and protein consumption, as well as their consequences on body weight gain by using an animal model of the menopause. Ovariectomy exacerbates the consumption of foods rich in lipids. Thus confirming an inhibitory action of 17β-estradiol (E2) on the consumption of these types of foods. This consumption stimulates body weight gain, which is promoted by the high caloric content of these foods and not by the amount consumed. Our results showed a direct involvement of D2 receptors in food choice. This choice would be made according to the two (2) isoforms of the D2 receptors. The D2/BR isoform directs towards a high carbohydrate consumption, without causing a gain in body weight. While D2/SUL, promotes high fat food consumption, causing an increase in body weight. In women, 17β-estradiol modulates the activity ratio between these two D2 receptor isoforms to ensure energy and homeostatic balance, stabilizing food intake and body weight.

Relationship of Toll-Like Receptors 2 and 4 Gene Polymorphisms with Essential Hypertension in Chinese Han Population

Objective: There are numerous studies suggesting that genetic polymor-phisms of inflammation factors Toll-like receptors 2 and 4 (TLR2, TLR4) might play a role in the pathophysiological process of hypertension. In this study, we evaluated the association in a sample of members of the Chinese Han population. Method: We selected four single nucleotide polymor-phisms (SNP) of TLR2 (rs3804099, rs3804100, rs7656411) and TLR4 (rs1927906) genes, and measured the distributions of genotypic and allelic frequencies in 1063 participants, including 391 essential hypertension pa-tients and 672 controls. Result: No significant differences in the genotypic and allelic frequencies of the four SNPs were detected between cases and controls. However, three haplotypes, CCG, TTG and TTT of TLR2, were significantly associated with a decrease in the risk of essential hyperten-sion (OR: 0.512, 95% CI: 0.397 - 0.660, P P = 0.0038;OR: 0.797, 95% CI: 0.667 - 0.952, P = 0.0122, respectively). Inversely, the risk of essential hypertension increased sig-nificantly in patients with the CTG, TCG or TCT haplotypes (OR: 2.924, 95% CI: 2.157 - 3.963, P P P Conclusion: Our study suggested that haplotypes (CCG, TTG, TTT, CTG, TCG and TCT) of TLR2 might have profound effects on the development of essential hypertension in the Chinese Han population.

Effects of Aprotinin on Serum Interleukin-2 and Soluble Interleukin-2 Receptor during Cardiopulmonary Bypass

Interleukin-2 and its receptor are of importance in regulating immunity responses. The changes of interleukin-2 (IL-2) and soluble interleukin-2 receptor (IL-2R) during heart valve (s) replacement operation and effects of aprotinin on them were observed. Twenty patients undergoing heart valve (s) replacement were randomly divided into two groups: control group (n=10) and apro- tinin group (n=10). In aprotinin group, 1 000 000 KIU aprotinin was given by vein injection and then 2 000 000 KIU was given as a bolus in prime. Blood samples were collected before CPB, right after CPB and on the 1st, 3rd and 7th postoperative day (POD) for serum IL-2 and sIL-2R determination. Results showed that after CPB, IL-2 was reduced and slL-2R increased. Meanwhile, serum IL-2R was lower in aprotinin group than that of control. It is concluded that the immunity depression after CPB is associated with low level of IL-2 and high level of sIL-2R and aprotinin can ameliorate the situation.

INTERLEUKIN-2 (IL-2) PRODUCTION AND INTERLEUKIN-2 RECEPTOR EXPRESSION IN PATIENTS WITH APLASTIC ANEMIA

IL-2 production and IL-2 receptor (Tac antigen) of the peripheral blood mononuclear cells in 30 patients with aplastic anemic (AA) were studied. We found that mononuclear cells from patients produce spontaneously IL-2 in the absence of exogenous lee-tin stimulation, the proportion of Tac+ cells in mononuclear cells increased. The release of IL-2 and or Tac antigen expression were elevated in almost every patient with AA. The plasma from patients stimulate mitogen-induced blastogenesis and Tac antigen expression of normal human lymphocytes. Immunological 1 abnormalities of patients with AA possibly might represents secondary response to bone marrow depression.

Changes in soluble interleukin-2 receptor level in serum and Na^+ -K^+ -exchanging ATPase activity in semen of infertile men caused by antisperm antibody

Aim: To explore the possible mechanisms of male infertility caused by antisperm antibody (AsAb). Methods: Thesoluble interleukin-2 receptor (sIL-2R) level in serum was analyzed by ELISA and Na^+ -K^+ -exchanging ATPase activi-ty in semen by phosphorus (Pi) assay. Results: The slL-2R level in serum was significantly higher and the Na^+ -K^+ -exchanging ATPase activity in semen significantly lower in AsAb positive infertile men when compared with thecontrols. Conclusion: The AsAb titer varies with the slL-2R level in serum. A decrease in Na^+ -K^+ -exchangingATPase activity in semen may play a role in male infertility caused by AsAb.

Interleukin-22 receptor 1 is expressed in multinucleated giant cells:A study on intestinal tuberculosis and Crohn’s disease

BACKGROUND It is challenging to distinguish intestinal tuberculosis from Crohn’s disease due to dynamic changes in epidemiology and similar clinical characteristics. Recent studies have shown that polymorphisms in genes involved in the interleukin (IL)- 23/IL-17 axis may affect intestinal mucosal immunity by affecting the differentiation of Th17 cells. AIM To investigate the specific single-nucleotide polymorphisms (SNPs) in genes involved in the IL-23/IL-17 axis and possible pathways that affect susceptibility to intestinal tuberculosis and Crohn's disease. METHODS We analysed 133 patients with intestinal tuberculosis, 128 with Crohn’s disease, and 500 normal controls. DNA was extracted from paraffin-embedded specimens or whole blood. Four SNPs in the IL23/Th17 axis (IL22 rs2227473, IL1β rs1143627, TGFβ rs4803455, and IL17 rs8193036) were genotyped with TaqMan assays. The transcriptional activity levels of different genotypes of rs2227473 were detected by dual luciferase reporter gene assay. The expression of IL-22R1 in different intestinal diseases was detected by immunohistochemistry. RESULTS The A allele frequency of rs2227473 (P = 0.030, odds ratio = 0.60, 95% confidence interval: 0.37-0.95) showed an abnormal distribution between intestinal tuberculosis and healthy controls. The presence of the A allele was associated with a higher IL-22 transcriptional activity (P < 0.05). In addition, IL-22R1 was expressed in intestinal lymphoid tissues, especially under conditions of intestinal tuberculosis, and highly expressed in macrophage-derived Langhans giant cells. The results of immunohistochemistry showed that the expression of IL-22R1 in patients with Crohn's disease and intestinal tuberculosis was significantly higher than that in patients with intestinal polyps and colon cancer (P < 0.01). CONCLUSION High IL-22 expression seems to be a protective factor for intestinal tuberculosis. IL-22R1 is expressed in Langhans giant cells, suggesting that the IL-22/IL-22R1 system links adaptive and innate immunity.

Fluence of Glucosidorum Tripterygii Totorum on joint and serum soluble interleukin-2 receptor in patients with ankylosing spondylitis

Objective The current study was designed to find out the effect of Glucosidorum Tripterygii Totorum (GTT) on the serum level of soluble interleukin-2 receptor (sIL-2R) in patient with ankylosing spondylitis (AS). Method 29 patients with active AS were selected to take GTT (1mg per kg) three times a day for one year. After that, its curative effect was evaluated. The serum level of sIL-2R of these patients was measured by sandwich ELISA method and was compared with that of normal subjects. Result The serum level of sIL-2R in active AS patients was obviously higher than that of the non-active AS patients. (P<0.01). The total effective rate of GTT on AS was 89.6%, while clinical relief rate 27.6%, obvious effective rate 44.8%, effective rate 17.2% and non-effective rate 10.4%. The patients’ serum level of sIL-2R after therapy was significantly lower than that before therapy except patients with no effect. (P<0.05). Conclusion GTT has positive curative effect on active AS patients and could cause obvious decrease of the serum level of sIL-2R. The serum level of sIL-2R can be used as an important index of activity of AS and as a guide of therapy.

Study of the Effect of Leeching on Plasma Endothelin and Soluble Interleukin-2 Receptor in Patients with Systemic Lupus Erythematosus

Objective: to explore the mechanism of leeching in treating systemic lupus erythematosus (SLE). Methods: Forty-four patients with SLE were randomly divided into conventional corticosteroid treated group (control group, n =20) and conventional treatment group with leeching intervention added (leeching group, n =24). Before and after treatment the concentration of plasma endothelin (ET) and soluble interleukin-2 receptor (sIL-2R) were determined. Results: Before treatment the level of plasma ET and sIL-2R in the SLE patients were all higher than those in the normal healthy group, ( P <0.01). But after treatment the level of these in both groups were significantly improved than those of before treatment ( P <0.05), and comparison between these two treated groups showed that the difference between them was significant ( P <0.05). Conclusion: Leeching added to conventional treatment of SLE could be more effective in improving the level of plasma ET and sIL-2R, and ameliorating the impairment of renal tissues.

Elevated pancreatic enzymes, IgM, soluble interleukin-2 receptor in anti-GADab(+) type 1 diabetes

Type 1 diabetes can be classified into immune-mediated diabetes (type 1A) and idiopathic diabetes, which lacks immunological evidence for beta cell autoimmunity (type 1B). Type 1A diabetes is characterized by the presence of the anti-glutamic acid decarboxylase antibody (anti-GADab). Fulminant type 1 diabetes is classified as type 1B diabetes, and characterized by the absence of anti-GADab, flu-like symptoms, and elevated serum exocrine pancreatic enzymes. We report a type 1 diabetic patient who showed flu-like symptoms, elevated serum exocrine pancreatic enzymes, and an extremely high-titer of anti-GADab, manifesting the characteristics of both type 1A and fulminant type 1 diabetes.

Central CB2 receptors in inflammation-driven neurodegeneration： dysregulation and therapeutic potential

In recent times there has been an intensification of interest in the pathological role of neuroinflammation in neurodegenerative disease. Neuroprotective strategies to slow, halt or reverse neuro- degeneration have not proven fruitful clinically, and the notion of a multi-hit hypothesis in the progression of neurodegenerative disease has steered focus towards other contributory pathological factors, particularly neuroinflammation. Neuroinflammation is believed to sustain the neurodegenerative pathology, forming a cy- clical and self-sustaining pathological process, with dying neurons activating microglia, which, once activated, can release several fac- tors that kill further neurons （reviewed in Blandini, 2013）.

Role of peroxisome proliferator-activated receptors gene polymorphisms in type 2 diabetes and metabolic syndrome

Metabolic syndrome(MetS) and type 2 diabetes mellitus(T2DM) are the serious public health problems worldwide.Moreover,it is estimated that MetS patients have about five-fold greater risk of the T2 DM development compared with people without the syndrome.Peroxisome proliferator-activated receptors are a subgroup of the nuclear hormone receptor superfamily of ligand-activated transcription factors which play an important role in the pathogenesis of MetS and T2 DM.All three members of the peroxisome proliferator-activated receptor(PPAR) nuclear receptor subfamily,PPARα,PPARp/5 and PPARγ are critical in regulating insulin sensitivity,adipogenesis,lipid metabolism,and blood pressure.Recently,more and more studies indicated that the gene polymorphism of PPARs,such as Leu^(162)Val and Val^(227)Ala of PPARα,+294T> C of PPARβ/δ,Pro^(12)Ala and C1431 T of PPARγ,are significantly associated with the onset and progressing of MetS and T2 DM in different population worldwide.Furthermore,a large body of evidence demonstrated that the glucose metabolism and lipid metabolism were influenced by gene-gene interaction among PPARs genes.However,given the complexity pathogenesis of metabolic disease,it is unlikely that genetic variation of a single locus would provide an adequate explanation of inter-individual differences which results in diverse clinical syndromes.Thus,gene-gene interactions and gene-environment interactions associated with T2 DM and MetS need future comprehensive studies.

Role of P2X_7 receptors in neuronal death in the retina

Acknowledgments： I would like to express my appreciation to Professor Puro DG for leading me to this research topic during my stay as a research fellow in his laboratory at the University of Michigan in 2001, and also to Professor Ikeda T forgiving me the opportunity to study abroad and then to continue to investigate this topic in the Department of Ophthalmology at Osaka Medical College, lapan.

GluN2B-NMDA receptors in Alzheimer's disease:beyond synapse loss and cell death

Alzheimer＇s disease （AD） is one of the most devastating dis- eases affecting the life and health of aging population. Two hallmarks of AD are senile plaques and neurofibrillary tan- gles, and AD is well known for the massive loss of neurons and impaired cognitive functions especially memory loss. Despite extensive search for effective treatment, available drugs have limited efficacy without affecting the course of AD. Significant efforts have been devoted to curb the pro- duction of amyloid [3 （A[3; the major component of plaques） or enhance the clearance of it, with the aim to reduce the accumulation of plaque in the brain. Antibodies that can bind A[3 to increase their removal have received a lot of at- tention although recent clinical trial results have been largely negative and disappointing （Panza et al., 2014）. Targets that are not directly related to A[3 have also been pursued. One such target is N-methyl-D-aspartate （NMDA） receptors （NMDARs）, a subclass of glutamate receptors. The antago- nist of NMDAR memantine has been approved for treating moderate to severe AD, although the exact mechanism un- derlying its action is still in debate （Kotermanski and John- son, 2009）.

Effects of Ovariectomy and 17<i>β</i>-Estradiol Replacement on Dopamine D2 Receptors in Female Rats: Consequences on Sucrose, Alcohol, Water Intakes and Body Weight

Background: Mechanisms underlying overeating-induced obesity in post-menopausal woman include functional lack of 17β-estradiol dysregulating dopamine D2 receptors, thereby inducing food addiction, glucose craving or alcohol dependence through reward circuitry. This study aimed at further understanding 17β-estradiol and dopamine D2 receptors interferences in the etiology of woman obesity. Method: Seventy-two Wistar female rats weighing 200 - 205 g, individually-housed, were divided into non-ovariectomized control (C = 6 groups) and ovariectomized rats (OVX = 6 groups) which were concurrently subjected to the following treatments: Non-drug-treated (DMSO vehicle), 17β-estradiol (E2, 5 μg/kg, s.c.), sulpiride (SUL, 20 mg/kg, i.p.), bromocriptine (BR, 0.1 mg/kg, i.p.), E2 + SUL or E2 + BR, designating the 6 constitutive groups of either control or ovariectomy. Within each experimental group, consumption of different solutions (10% alcohol, 10% sucrose and water) as well as food intake and body weight were daily measured, for 10 consecutive days. Results: This study indicated that D2S was a specific inducer of alcohol and food intakes, but reduced sugar consumption. In addition, 17β- estradiol regulated the body weight set point, modulating D2S functions towards increased food intake at lower weights and decreased food intake at higher weights. D2S met the slow genomic actions induced by 17β-estradiol. Conversely, D2L inhibited alcohol and food intakes, but induced specifically sugar consumption, thereby regulating blood glucose levels and promoting energy expenditure in reducing body weight. Indeed, 17β-estradiol exerted a tonic inhibition on D2L which was released by OVX, exacerbating sugar intake and increasing body weight. D2L mediated the rapid metabolic effects of 17β-estradiol. Conclusion: Our results supported physiological data reporting that activation of the mostly expressed presynaptically D2S-class autoreceptors decreased dopamine release stimulating food intake, whereas activation of the predominantly postsynaptic isoform D2L receptors increased dopamine activity inhibiting food intake. Our studies indicated that 17β-estradiol acted on the two types of D2 receptors showing opposite functions to equilibrate energy intake vs. expenditure for weight set point regulation. Our data also supported biochemical findings reporting that 17β-estradiol induced D2 genes transcriptional regulation, thereby involving both types of D2 receptors in the etiology of obesity. The combined dysregulated effects of D2L and D2S receptors, as 17β-estradiol was lacking, would be causal factors underlying the etiology of obesity.

Expression of estrogen receptor alpha,nerve growth factor,interleukin-2,and androgen receptor in the cerebellum of ovariectomized rats following soybean isoflavone treatment

BACKGROUND： Studies have shown that estrogen receptor alpha （ERα）, nerve growth factor （NGF）, interleukin-2 （IL-2）, and androgen receptor （AR） expression in the cerebellum decreases when estrogen levels decrease in vivo. Soybean isoflavone, a type of non-steroid estrogen with similar molecular structure and function to estradiol, exhibits estrogen-like characteristics. OBJECTIVE： To investigate the effects of various doses of soybean isoflavone on expression of ERa, NGF, IL-2, and AR in the cerebellum of ovariectomized rat, and to determine whether there is a dose-dependent effect.DESIGN, TIME AND SETTING： Controlled trial at the cellular and molecular level. The study was performed at the Experimental Animal Engineering Center, College of Veterinary Medicine, Sichuan Agricultural University from July 2006 to May 2008. MATERIALS： Soybean isoflavone, comprised of daidzin, genistein and isoflavone, was provided by Taiyuan Yuantai Biochemical Industry, China. The ERα, NGF, IL-2, and AR in situ hybridization kit, rabbit anti-rat ERa, NGF, IL-2, and AR monoclonal antibodies, and SABC kit were purchased from Wuhan Boster Biological Technology, China. METHODS： A total of 50 female, Sprague Dawley rats, aged 3 months, were randomly assigned to 5 groups, with 10 animals in each group. With the exception of the sham-operation group （abdominal cavity opening alone）, all rats underwent bilateral ovariectomy. At 14 days after surgery, rats in the high-, middle-, and low-dose soybean isoflavone groups were subcutaneously injected with 1.5, 1.0, and 0.5 mg/kg soybean isoflavone, respectively, every 2 days for 6 consecutive weeks. Rats in the sham-operation and ovariectomized groups were subcutaneously injected with absolute alcohol （0.5 mL/kg）. MAIN OUTCOME MEASURES： Expression levels and distribution of ERα, NGF, IL-2, and AR in the cerebellum were detected by immunohistochemistry and in situ hybridization. RESULTS： Compared with the sham-operation group, immunoreactive products and hybridization signals of ERa, NGF, IL-2, and AR were significantly decreased in the cerebellar cortex and nuclei of ovariectomized rats （P 〈 0.05 or P 〈 0.01）, but increased following soybean isoflavone treatment. In particular, levels of the high-dose soybean isoflavone group were almost restored to levels of the sham-operation group （P 〉 0.05）. The immunoreactive products were primarily located in the cytoplasm and neurites, and rarely in the cell membrane and nuclei. However, the hybridization signals were predominantly located in the nuclei, but rarely in the cytoplasm, cell membrane, or neurites. CONCLUSION： Soybean isoflavone upregulated ERα, NGF, IL-2, and AR protein and gene expression in a dose-dependent manner, and played an important role in sustaining and protecting structure and function of cerebellar neurons. Moreover, the similarity of expression patterns of these molecules indicated that they were mutually interactive during the regulation of soybean isoflavone to the cerebellum.

P2X receptors in maintenance and differentiation of neural progenitor cells

Purinergic receptors are among the first cell surface receptors expressed during embryonic development （Burnstock and Ulrich, 2011）. These are characterized based on their pharmacological properties of being activated by adenosine or purine/pyrimidine nucleotides as P1 and P2 receptors. P2 receptors are further classified by their structure as P2Y metabotropic and P2X ionotropic receptors.

Detection of Circulating Autoantibodiestoβ_2-Adrenergic Receptors in Patients with Asthma

To investigate the roles of autoantibodies to β 2 adrenergic receptors in the pathogenesis of asthma, the positive chronotropic action of the β 2selective adrenergic agonist, clenbuterol, was investigated on cultured neonatal rat cardiomyocytes, firstly. Then we detected the autoantibodies to β 2adrenergic receptors through the sera of patients with asthma could inhibit the positive chronotropic action of clenbuterol. The results showed that all the sera of the patients with asthma (16 cases) had the autoantibodies to β 2 adrenergic receptors; in contrast, none of the control subjects (20 cases) had the autoantibodies to β 2 adrenergic receptors, and that the inhibitory autoantibodies were IgG type. This study suggests that the autoantibodies to β 2 adrenergic receptors may play an important role in the pathogenesis of asthma.

Uridine adenosine tetraphosphate acts as a pro-angiogenic factor in vitrothrough purinergic P2Y receptors

OBJECTIVE Uridine adenosine tetraphosphate(Up4A),a dinucleotide,contains both purine and pyrimidine moieties,and exerts its vascular influence via activation of purinergic receptors.Here,we aimed to investigate the effects of Up4 A on angiogenesis and the putative purinergic receptors(PR)involved in this process.METHODS Tubule formation assay was performed in 3D matrix system.In this assay,human umbilical vein endothelial cells(HUVECs)were co-cultured with pericytes with various Up4 A doses(0,1,2.5,5,10 and 20μmol·L-1)in the absence and presence of P2Y6 R antagonist MRS2578(10μmol·L-1)for 5d.Expression profile of PR subtypes and angiogenic factors was assessed in HUVECs by q-PCR with and without P2Y6 R antagonist.RESULTS No difference in initial tubule formation was detected between Up4 A stimulation and control conditions at day 2.In contrast,a significant increase in vascular density in response to Up4 A was observed at day 5.Up4 A at a dose of 2.5and 5μmol·L-1 promoted total tubule length(by-1.89 fold and-2.23fold),number of tubules(by-1.71 fold and-1.89fold)as well as number of junctions(by-2.24 fold and-2.80fold),all of which were inhibited by MRS2578.Further increase in Up4 A dose to10 and 20μmol·L-1 did not induce an increase in these vascular parameters as compared to non-treated controls.Moreover,Up4 A increased mRNA level of P2YRs(P2Y2R,P2Y4 R and P2Y6R)but not P2XR(P2X4R and P2X7R)or P1R(A2AR and A2BR),while Up4 A upregulated VEGFA and ANGPT1 but not VEGFR2,ANGPT2,Tie1 and Tie2at mRNA level.Transcriptional upregulation of P2 YRs and angiogenic factors by Up4 A was inhibited by MRS2578.CONCLUSION Up4 A is functionally capable of promoting tubule formation in vitro co-culture system.This process is likely mediated by activation of pyrimidine-favored P2 YRs but not P2 XR or P1 Rs,and involves stimulation of well known angiogenic factors.

Influences of NR2B-containing NMDA Receptors Knockdown on Neural Activity in Hippocampal Newborn Neurons

Summary： Adult-bom neurons undergo a transient period of plasticity during their integration into the neural circuit. This transient plasticity may involve NMDA receptors containing NR2B, the major sub unit expressed at early developmental stages. The main objective of the present study was to investigate the effects of NR2B gene knockdown on the functional integration of the adult-born granule cells gen- erated from the subgranule zone （SGZ） in the hippocampus. The small interfering RNA （siRNA） was used to knock down the NR2B gene in the adult-born hippocampal neurons. In the functional integration test, the mice were exposed to a novel environment （open field arena）, and the expression of c-fos was immunohistochemically detected in the hippocampus. After exposure to the novel environment, siRNA-NR2B mice were significantly different from control mice in either the number of squares or the number of rears they crossed, showing decreased horizontal and vertical activity （P〈0.05）. Moreover, the c-fos expression was increased in both control and siRNA-NR2B mice after open field test. But, it was significantly lower in siRNA-NR2B neurons than in control neurons. It was concluded that the neu- ral activity of newborn neurons is regulated by their own NR2B-containing NMDA glutamate receptors during a short, critical period after neuronal birth.

Expression of prostaglandin E_2 receptors in rat hippocampus

BACKGROUND: Prostaglandin E2 (PGE2) can directly regulate toxic injury of hippocampal neurons through participation by its receptor. Increase of excitability of hippocampal membrane and long-term synaptic elasticity are closely related to PGE2, PGD2 and PGF2A. This suggests that PGE2 may be a key molecule of neuronal signal passage and regulate the existence of neurons through its receptor. However, which isoforms of PGE2 receptor expressing in hippocampal neurons is still unclear. OBJECTIVE: To research the subtype expression of PGE2 receptor in hippocampus of rats through mRNA transcription and protein interpretation. DESIGN: Animal studies with random, control and operator and designer double-blind methods. SETTING: University of South Carolina, Animal Center. MATERIALS: Sprague-Dawley rats, aged 12 weeks, weighing 200 g, females 48 and males 48, were selected from Animal Center in South Carolina University. Tri ReagentTM kit was provided by Molecular Research Center, USA. METHODS: The experiment was carried out in Animal Center in South Carolina University from January to December 2005. The expression of the PGE2 receptors was profiled and compared in rat hippocampus using real-time RT-PCR and Western-blot techniques. MAIN OUTCOME MEASURES: Expression of PGE2 receptors in various isoforms of hippocampal neurons of rats. RESULTS: mRNAs of all four EP1-4 subtypes were detected in the hippocampus. Western-blot data showed consistently detectable bands at approximately Mr 50 000 of EP1, Mr 40 000 and Mr 52 000 of EP2, Mr 45 000, Mr 57 000 and Mr 105 000 of EP3, and Mr 46 000 of EP4. CONCLUSION: Identifying four subtypes of EPs heterogeneously expresses in the hippocampus.