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AIM DDT1 MF-2 hamster smooth muscle cells were used to investigate the role of α1B-adrenoceptor (AR) in the cell proliferation and its signaling pathway. METHODS DNA synthesis was measured by ［3H］thymidine (TdR) incorporation and the cell cycle was determined by flow cytometry. The actions of several inhibitors and activators of second messenger on NE-induced DNA synthesis were investigated. RESULTS NE (0.1～1 μmol*L-1) elicited significant concentration-dependent stimulation of DDT1 MF-2 cell proliferation. The proliferative effect caused by α1B-AR was blocked by PLC inhibitor (U73122, 10 μmol*L-1), Ca2+/ATPase inhibitor (cyclopiazonic acid, 10 μmol*L-1), intracellular Ca2+ chelator (BAPTA/AM, 10 μmol*L-1), PKC inhibitors (RO-31-8220, 0.1 μmol*L-1 and calphostin C, 0.1 μmol*L-1), TK inhibitors (tyrphostin A25, 10 μmol*L-1 and genistein, 10 μmol*L-1), and MEK1/2 inhibitor (PD 98059, 10 μmol*L-1). CONCLUSION α1B-AR subtypes stimulate DDT1 MF-2 cells growth and its signal pathway is related to the PLC activation、Ca2+ release、PKC、TK and ERKs activation.
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Objective: To better understand the antagonistic effect of Xiao Long Tong Bi (XLTB), a Chinese herb medicine, on α1-adrenoceptor (α1-AR). Methods: (1) Radio ligand binding assay . Specific 125I-BE2254(2-β(4-hdroxyphenyl)-ethyl amino-methyl-tetralone) binding was measured by incubating membrane of canine cerebral cortex with a single concentration of 125I-BE2254 in the presence of 15 concentrations of XLTB. Half-effectual concentration of inhibition (IC50) and Hill coefficients (nH) were determined by Hill plots. (2) Contractile responses of rat prostate strip in vitro were determined. pKB values for XLTB in competitively inhibiting NE-stimulated contraction of tissues were measured by the method of Ainlakshana. Results: XLTB competitively inhibited binding of 125I-BE2254 to α1-AR in a concentration -dependent manner. IC50 values for XLTB in canine cerebral cortex were (34.0±6.0) g*L－1, the Hill efficiency value (0.7±0.1) was significantly decreased from unity. Contractile studies showed that XLTB competitively antagonized the NE concentration-response curve with pKB values of (37.0±11.0) g*L－1 or (30.0±8.0) g*L－1 when XLTB concentration was 70 g*L－1 or 170 g*L－1, respectively. The pKB values for XLTB in antagonizing NE-induced contraction of tissues were showed to fit in well with the IC50 values on rat prostate. Conclusion: These results suggest that XLTB appears to be a competitive antagonist for α1-AR.
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AIM: To define the gene expression changes of vascular smooth muscle cells (VSMCs) in response to norepinephrine (NE). METHODS: The expression adrenergic receptors (AR) were determined by radioligand binding assay in A7r5 cells. Gene expression profiles were identified by cDNA microarray after A7r5 cells were treated with NE for 24 h, and mRNA expressions of ? 1A -AR and ? 1B -AR were confirmed by real-time PCR. RESULTS: ? 1-AR and ?-AR existed in A7r5 cells. Seventy-five genes with changed expression in response to NE were screened out. These genes are involved in cell structure, cell/organism defense, metabolism, signal transduction and so on. ? 1A -, ? 1B -AR mRNA expression identified by microarray and realtime quantitive PCR displayed similar patterns. CONCLUSIONS: Gene expression profile in response to NE was analyzed comprehensively with the microarray technique. NE induces many kinds of different function genes in A7r5 cells, which may provide a novel insight into the particular role of NE that modulates multiple aspects of biological function in VSMCs. [
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adrenergic receptor is the third subtype of ?-adrenergic receptors. The genetic structure and pharmacological property of ? 3-adrenergic receptor are markedly distinguished from ? 1-and ? 2-adrenergic receptor subtypes. Recently studies show that myocardial ? 3-adrenergic receptor mediates negative inotropic effect through Gi-protein/NO/cGMP pathway, the expression of ? 3-adrenergic receptor and negative inotropic effect mediated by ? 3-adrenergic receptor are increased in heart failure. However, because of the low expression of ? 3-adrenergic receptor in the heart, the actual pathophysiological significance of ? 3-adrenergic receptor remains unknown.
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AIM DDT1 MF 2 hamster smooth muscle cells were used to investigate the role of ? 1B adrenoceptor (AR) in the cell proliferation and its signaling pathway. METHODS DNA synthesis was measured by [ 3H]thymidine (TdR) incorporation and the cell cycle was determined by flow cytometry. The actions of several inhibitors and activators of second messenger on NE induced DNA synthesis were investigated. RESULTS NE (0 1～1 ?mol?L -1 ) elicited significant concentration dependent stimulation of DDT1 MF 2 cell proliferation. The proliferative effect caused by ? 1B AR was blocked by PLC inhibitor (U73122, 10 ?mol?L -1 ), Ca 2+ /ATPase inhibitor (cyclopiazonic acid, 10 ?mol?L -1 ), intracellular Ca 2+ chelator (BAPTA/AM, 10 ?mol?L -1 ), PKC inhibitors (RO 31 8220, 0 1 ?mol?L -1 and calphostin C, 0 1 ?mol?L -1 ), TK inhibitors (tyrphostin A25, 10 ?mol?L -1 and genistein, 10 ?mol?L -1 ), and MEK1/2 inhibitor (PD 98059, 10 ?mol?L -1 ). CONCLUSION ? 1B AR subtypes stimulate DDT1 MF 2 cells growth and its signal pathway is related to the PLC activation、Ca 2+ release、PKC、TK and ERKs activation.
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Impact of air pollution on cardiovascular d is eases has been established. As the main source of city air pollution, particulat e matter has been demonstrated an independent correlation with incidence and mor tality of cardiovascular diseases. The mechanisms are not clear. Several plausib le mechanistic pathways have been described, including inflammation induced by o xidative stress, the followed enhanced coagulation/thrombosis resulted in instab ility of atherosclerosis, the promotion of ischemic heart diseases and imbalance of autonomic nerve tone resulted in the occurrence of arrhythmia. The article p rovides a review of the mechanisms on air pollution and cardiovascular diseases and suggestions for further research.