OBJECTIVETo explore the effect of organophosphorus insecticides (OPs) on G protein-coupled receptor kinase 2 mediated phosphorylation of M2 muscarinic receptors in vitro and to understand an alternative target of the OPs for human and other animals.

METHODSThe acetylcholine M2 muscarinic receptors (mAChR2) were purified from rat brain by single step affinity chromatography. In vitro experiments, the purified mAChR2, G-protein coupled receptor kinase 2 (GRK2) and the (gamma-p32) labeled ATP were incubated with paraoxon (PO), chlorpyrifos oxon (CPO) or chlorpyrifos (CPF) of varying concentrations. The proteins were separated by the polyacrylamide gel electrophoresis. The gels were dried and the phosphorylation of mAChR2 was detected with autoradiograms. Bands containing M2 receptor were excised and counted by liquid scintillation.

RESULTSCPO inhibited phosphorylation of M2 muscarinic receptors by GRK2 with a median inhibition concentration (IC(50)) at 70 micromol/L. CPF also inhibited M2 receptors phosphorylation, but was less potent and less efficacious than that of CPO. PO and parathion (PT) had little effect on the receptor phosphorylation under the same conditions. CPO and CPF didn't inhibit the beta2 Adrenalin (beta2-AR) receptor phosphorylation also mediated by GRK2.

CONCLUSIONCPO and CPF can selectively inhibit the GRK2 mediated mAChR2 phosphorylation while PO and PT have no this effect.

Animals ; Chlorpyrifos ; analogs & derivatives ; toxicity ; Cholinesterase Inhibitors ; toxicity ; G-Protein-Coupled Receptor Kinase 2 ; Paraoxon ; toxicity ; Phosphorylation ; Rats ; Receptor, Muscarinic M2 ; metabolism ; beta-Adrenergic Receptor Kinases ; metabolism ; physiology

G protein-coupled receptor kinase 5 (GRK5) plays an important role in the regulation of GPCR-transduced signals. Our previous study showed that acute administration of morphine could significantly increase GRK5 mRNA level in the cerebral cortex and hippocampus of the rat brain. The current study investigated the potential effects of acute administration of addictive drugs including morphine, heroine and cocaine on GRK5 mRNA level in the rat brain using in situ hybridization and analyzed the effects of acute and chronic morphine treatments on GRK5 protein level in the rat brain using Western blotting assay. Our results showed that 2 h after the initial morphine (10 mg/kg), cocaine (15 mg/kg) and heroine (1 mg/kg) treatment, the mRNA level of GRK5 in the parietal cortex increased about 110% (P<0.01), 70% (P<0.05) and 100% (P<0.01), respectively. In the temporal cortex, GRK5 mRNA level increased about 90% (P<0.01), 40% (P<0.05) and 80.0% (P<0.01), respectively . In the hippocampus, the mRNA level of GRK5 increased about 60% (P<0.01), 30% (P<0.05) and 80% (P<0.01). However, the mRNA level of GRK5 remained unchanged after acute morphine, cocaine or heroine treatment. In the cerebral cortex of the rat brain, the acute administration of morphine (NS-Mor) increased GRK5 protein level by about 60% while the chronic morphine treatment (Mor-Mor) increased GRK5 protein level even higher [about 130% compared with the control group (chronic saline treatment, NS-NS) group, P<0.01]. In the hippocampus, GRK5 protein level remained unchanged after acute administration of morphine (P>0.1),while the level of GRK5 protein tended to decrease after chronic morphine treatment (P=0.098). In the thalamus, acute morphine treatment caused no change in GRK5 protein level (P>0.1) while after chronic morphine treatment, GRK5 protein level decreased significantly (more than 90%, P<0.01), Taken together, our results indicate that addictive drugs can regulate GRK5 in the rat brain on protein level as well as on mRNA level and suggest that GRK5 may play a role in addiction of psychoactive substances.
Animals ; Brain ; metabolism ; Cocaine ; adverse effects ; G-Protein-Coupled Receptor Kinase 5 ; Heroin ; adverse effects ; Male ; Morphine ; adverse effects ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Substance-Related Disorders ; metabolism

OBJECTIVETo study the effects of the Weinaokang (WNK), the active compounds extracted from Ginkgo, Ginseng, and saffron, on ischemia/reperfusion (I/R)-induced vascular injury to cerebral microvessels after global cerebral ischemia.

METHODSMale C57BL/6J mice were randomly divided into 5 groups (10 animals/group): the sham group (0.5% CMC-Na, 20 mL/kg), the I/R model group (0.5% CMCNa, 20 mL/kg), the I/R+Crocin control group (20 mg/kg), the I/R+high dose WNK group (20 mg/kg), and the I/R+low dose WNK group (10 mg/kg). Bilateral common carotid artery occlusion (BCCAO, 20 min) in mice, followed by 24 h reperfusion, was built. The generation of nitric oxide (NO), the activity of nitric oxide synthase (NOS), the phosphorylation of extracellular signal-regulated kinase1/2 (ERK1/2), and the expression of matrix metalloproteinases-9 (MMP-9) and G protein-coupled receptor kinase 2 (GRK2) in cortical microvascular homogenates were evaluated. The ultrastructural morphology of cortical microvascular endothelial cells (CMEC) was observed.

RESULTSThe transient global cerebral ischemia (20 min), followed by 24 h of reperfusion, significantly promoted the generation of NO and the activity of NOS. The reperfusion led to serious edema with mitochondrial injuries in the cortical CMEC, as well as enhanced membrane GRK2 expression and reduced cytosol GRK2 expression. Furthermore, enhanced phosphorylation of ERK1/2 and decreased expression of MMP-9 were detected in cortical microvessels after I/R (20 min/24 h). As well as the positive control Crocin (20 mg/kg, 21days), pre-treatment with WNK (20, 10 mg/kg, 21 days) markedly inhibited nitrative injury and modulated the ultrastructure of CMEC. Furthermore, WNK inhibited GRK2 translocation from cytosol to the membrane (at 20 mg/kg) and reduced ERK1/2 phosphorylation and MMP-9 expression in cortical microvessels.

CONCLUSIONWNK and its active compounds (Crocin) are effective to suppress I/R-induced vascular injury to cerebral microvessels after global cerebral ischemia with the target on GRK2 pathways.

Animals ; Brain Ischemia ; drug therapy ; metabolism ; Cerebral Cortex ; blood supply ; drug effects ; metabolism ; ultrastructure ; Drug Evaluation, Preclinical ; Drugs, Chinese Herbal ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; G-Protein-Coupled Receptor Kinase 2 ; metabolism ; Male ; Matrix Metalloproteinase 9 ; metabolism ; Mice ; Mice, Inbred C57BL ; Microvessels ; drug effects ; metabolism ; pathology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Phosphorylation ; Reperfusion Injury ; drug therapy ; metabolism ; Signal Transduction ; drug effects ; Tissue Distribution ; drug effects

BACKGROUND: Mucin synthesis in airways has been reported to be regulated by the epidermal growth factor receptor (EGFR) system. Epidermal growth factor receptor transactivation was identified as a critical element in G-protein-coupled receptors (GPCRs)-induced mitogenic signaling. EGF receptor transactivation by G-protein-coupled receptors requires metalloproteinase cleavage of proHB-EGF. This study was hypothesized that lipopolysaccharide (LPS)-induced mucin production associates with epidermal growth factor receptor transactivation, and MUC5AC production associates with epidermal growth factor receptor transactivation by G-protein-coupled receptors that regulates by metalloproteinase. METHOD: MUC5AC mucin production was examined in NCI-H292 cells and MUC5AC protein synthesis was assessed using ELISA. For the evaluation of mechanism of LPS-induced MUC5AC production, TNFalpha was measured using ELISA with or without pretreatment of heterotrimeric G-protein inhibitor, mastoparan. MUC5AC protein was measure with pretreatment of polyclonal TNFalpha antibody or mastoparan on LPS-induced MUC5AC production. For the evaluation of relation of G-protein and MUC5AC production, G-protein stimulant, mastopara-7, or matrix metalloproteinase, ADAM10, was added to NCI-H292 cells. MUC5AC protein was measure with pretreatment of polyclonal EGF antibody on mastoparan-7-induced MUC5AC production. RESULTS: LPS alone did not increase significantly MUC5AC production. LPS with TGFalpha induced dose-dependently MUC5AC production in NCI-H292 cells. LPS increased dose-dependently TNFalpha secretion, which was inhibited by mastoparan. LPS with TGFalpha-induced MUC5AC production was inhibited by neutralizing polyclonal TNFalpha antibody, mastoparan or AG 1472. Mastoparan-7 or ADAM10 increased dose-dependently MUC5AC production, which was inhibited by polyclonal neutralizing EGF antibody. CONCLUSION: In LPS-induced MUC5AC synthesis, LPS causes TNFalpha secretion, which induces EGFR expression. EGFR tyrosine kinase phosphorylation result in MUC5AC production. EGF-R transactivation by G-protein-coupled receptors requires matrix metalloproteinase cleavage of proHB-EGF.
Enzyme-Linked Immunosorbent Assay ; Epidermal Growth Factor ; GTP-Binding Proteins ; Mucins ; Mucus* ; Phosphorylation ; Protein-Tyrosine Kinases ; Receptor, Epidermal Growth Factor ; Receptors, G-Protein-Coupled ; Signal Transduction* ; Transcriptional Activation ; Transforming Growth Factor alpha ; Tumor Necrosis Factor-alpha

BACKGROUND/AIMS: Several disorders of the gastrointestinal tract are associated with abnormal serotonin (5-HT) signaling or metabolism where the 5-HT3 and 5-HT4 receptors are clinically relevant. The aim was to examine the distribution of 5-HT3, 5-HT4, and 5-HT7 receptors in the normal human colon and how this is associated with receptor interacting chaperone 3, G protein coupled receptor kinases, and protein LIN-7 homologs to extend previous observations limited to the sigmoid colon or the upper intestine. METHODS: Samples from ascending, transverse, descending, and sigmoid human colon were dissected into 3 separate layers (mucosa, longitudinal, and circular muscles) and ileum samples were dissected into mucosa and muscle layers (n = 20). Complementary DNA was synthesized by reverse transcription from extracted RNA and expression was determined by quantitative or end point polymerase chain reaction. RESULTS: The 5-HT3 receptor subunits were found in all tissues throughout the colon and ileum. The A subunit was detected in all samples and the C subunit was expressed at similar levels while the B subunit was expressed at lower levels and less frequently. The 5-HT3 receptor E subunit was mainly found in the mucosa layers. All splice variants of the 5-HT4 and 5-HT7 receptors were expressed throughout the colon although the 5-HT4 receptor d, g, and i variants were expressed less often. CONCLUSIONS: The major differences in 5-HT receptor distribution within the human colon are in relation to the mucosa and muscular tissue layers where the 5-HT3 receptor E subunit is predominantly found in the mucosal layer which may be of therapeutic relevance.
Colon* ; Colon, Sigmoid ; DNA, Complementary ; G-Protein-Coupled Receptor Kinases ; Gastrointestinal Tract ; Humans ; Ileum ; Intestines ; Metabolism ; Mucous Membrane ; Polymerase Chain Reaction ; Receptors, Serotonin ; Receptors, Serotonin, 5-HT3 ; Receptors, Serotonin, 5-HT4 ; Reverse Transcription ; RNA ; Serotonin

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.
Adrenergic beta-Agonists/*pharmacology ; Aging/*drug effects ; Animals ; Epinephrine/*pharmacology ; G-Protein-Coupled Receptor Kinase 2/metabolism ; G-Protein-Coupled Receptor Kinase 3/metabolism ; Glucagon/pharmacology ; *Gluconeogenesis/drug effects ; Male ; Models, Biological ; Phosphorylation ; Rats ; Rats, Inbred F344 ; Receptors, Adrenergic, beta-2/agonists/metabolism

The effects of glucagon and epinephrine on gluconeogenesis in young (4 month) and old (24 month) Fisher 344 rat hepatocytes were compared. In contrast to glucagon, which had a similar effect on gluconeogenesis in both young and old cells, epinephrine caused a smaller increase in gluconeogenesis in old rat hepatocytes than in young hepatocytes. beta2 adrenergic receptor (beta2-AR) expression slightly decreased in aged rat liver, and there were differences between young and old hepatocytes in their patterns of G protein coupled receptor kinases, which are involved in the activation of beta2-AR receptor signal desensitization. The major isoform of the kinase changed from GRK2 to GRK3 and the expression of beta-arrestin, which is recruited by the phosphorylated beta2-AR for internalization and degradation, increased in aged rat liver. GRK3 overexpression also decreased the glucose output from young rat hepatocytes. We conclude that an age-associated reduction in epinephrine-induced gluconeogenesis occurs through the epinephrine receptor desensitizing system.
Adrenergic beta-Agonists/*pharmacology ; Aging/*drug effects ; Animals ; Epinephrine/*pharmacology ; G-Protein-Coupled Receptor Kinase 2/metabolism ; G-Protein-Coupled Receptor Kinase 3/metabolism ; Glucagon/pharmacology ; *Gluconeogenesis/drug effects ; Male ; Models, Biological ; Phosphorylation ; Rats ; Rats, Inbred F344 ; Receptors, Adrenergic, beta-2/agonists/metabolism

beta-adrenergic receptors (betaAR) belong to the large family of G protein-coupled receptors that form the interface between the sympathetic nervous and cardiovascular systems. G protein-coupled receptors undergo adaptation to repeated or prolonged agonist stimulation, which is termed desensitization. Significant betaAR desensitization occurs with the development of cardiac hypertrophy and heart failure, and uncoupling of betaARs and defects in this pathway might be primary elements underlying the transition from compensated to uncompensated cardiac failure. Decreasing the level of myocardial betaARK1 in established heart failure is a novel approach to improving impaired betaAR receptor function, and potentially alter the pathogenesis of this disease.
beta-Adrenergic Receptor Kinases ; Cardiomegaly* ; Cardiovascular System ; Heart Diseases* ; Heart Failure* ; Heart* ; Humans ; Receptors, Adrenergic, beta

BACKGROUND: Beta-adrenergic receptor Kinase 1(betaARK1) is a serine/threonine kinase attached, which inhibits the coupling of beta-adrenergic receptor with G-protein. Myocardial betaARK1 level is usually elevated in heart failure and hypertrophy, but it is not known whether the circulating betaARK1 level is related with the degree of cardiac hypertrophy. This study was performed to evaluate the association of the betaARK1 level in circulating mononuclear leukocytes(MNL) in untreated hypertension with left ventricular mass in hypertensive patients. Method: Nineteen non-treated hypertensive patients were included for this study. High blood pressure was confirmed when systolic BP is over 150 mmHg or diastoli BP is over 95 mmHg. Echocardiography was performed to evaluate the degree of hypertrophy by measuring the left ventricular mass index(LVMI) and relative wall thickness(RWT), and test the LV function by measuring the ejection fraction(EF) according to ASE guideline. At the same time, blood was collected from each patient and MNL were isolated by gradient centrifuge with Ficoll-400. Total RNA was purified from MNL and semi-quantitative RT-PCR was performed. After reverse transcription, PCR was done with primers for human betaARK1 and GAPDH as external control. betaARK1 levels were expressed by ratio to GAPDH level and estimated the relations with clinical and Echocardiographic parameters. Result: We studied confirmed 19 hypertensive patients(10 men and 9 women, mean age of 50.6 years). Echocardiographically measured indices(mean+/-SD) were as follows; LVMI(137.3+/-30.6g/m2), PWT(0.53+/-0.09) and EF(54.6+/-8.5%). Ratio of betaARK1 levels to GAPDH was from 0.10 to 0.96 (0.62+/-0.25). betaARK1 levels were correlated with LVMI(correlation coefficient: r=.502, p=.029) and RWT(r=.627, p=.004). But Systolic BP(r=0.009, p=.93), diastolic BP(r=.07, p=.85) or EF(r=.045, p=.84) were not related to level of betaARK1. CONCLUSIONS: The betaARK1 level of circulating MNL was correlated well with the degree of the cardiac hypertrophy estimated by LVMI and RWT. This data suggests that activation of sympatho-adrenal system would exert a major role in developing cardiac hypertrophy and we can expect the decreased responsiveness to catecholamine in the heart of hypertensive patients. betaARK1 in circulating MNL might be used as a predictor or marker for LV hypertrophy in hypertensive patients.
beta-Adrenergic Receptor Kinases ; Cardiomegaly ; Echocardiography ; Female ; GTP-Binding Proteins ; Heart ; Heart Failure ; Humans ; Hypertension ; Hypertrophy ; Leukocytes, Mononuclear* ; Male ; Phosphotransferases ; Polymerase Chain Reaction ; Reverse Transcription ; RNA

OBJECTIVETo explore the correlation of lymphocyte G protein-coupled receptor kinases 2 (GRK2) expression of the very elderly with chronic heart failure (HF) and heart ejection fraction (EF).

METHODS16 elderly patients with chronic heart failure were divided into 2 groups as following: EF < 45% (n=7), EF > or = 45% (n=9); and health elderly as control (n=8). Lymphocytes were obtained from blood, reverse transcription polymerase chain reaction were used to measure GRK2 mRNA levels.

RESULTSLymphocyte GRK2 mRNA levels of EF < 45% group were higher than that of EF > 45% group, which were greater than that of control.

CONCLUSIONElevation of lymphocyte GRK2 levels in HF is associated with heart EF, lymphocytes may provide a surrogate for monitoring cardiac GRK2 in human HF.

Aged, 80 and over ; Chronic Disease ; G-Protein-Coupled Receptor Kinase 2 ; genetics ; metabolism ; Heart Failure ; blood ; physiopathology ; Humans ; Lymphocytes ; metabolism ; Male ; RNA, Messenger ; genetics ; metabolism ; Stroke Volume ; physiology