Du, Juan. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 110-134). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Kwan Hiu Yee. / "June 2006." / 2+ in the title is superscript. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (p. 131-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese.

Attempts were made to determine the pore properties, such as permeability, rectification and voltage-dependent block, of the putative TRPV4-TRPC1 channel. We demonstrated that this putative TRPV4-TRPC1 heterotetrameric channels displays distinct property different (although not drastically different) from TRPV4 homotetrameric channel with regard to I-V relation, kinetics of cation current, cations permeability and rectification properties. Together, the data from FRET and functional studies both suggest that heterologous expression of TRPV4 and TRPC1 can produce functional TRPV4-TRPC1 heterotetrameric channel. / Hemodynamic blood flow is one of most important physiological factors that control vascular tone. Flow shear stress acts on the endothelium to stimulate the release of vasodilators such as nitric oxide (NO), prostacyclin and endothelium-derived hyperpolarizing factors, causing endothelium-dependent vascular relaxation. In many cases, a key early signal in this flow-induced vascular dilation is Ca2+ influx in endothelial cells in response to flow. There is intense interest in searching for the molecular identity of the channels that mediate flow-induced Ca2+ influx. The present study aimed at identifying an interaction of TRPV4 with TRPC1, and investigating functional role of such a complex in flow-induced Ca2+ influx / In functional study, flow elicited a [Ca2+]i rise in TRPV4-expressing HEK cells. Co-expression of TRPC1 with TRPV4 markedly prolonged this [Ca2+]i transient, and it also enabled this [Ca2+]i transient to be negatively modulated by protein kinase G (PKG). Furthermore, this [Ca2+]i rise was inhibited by an anti-TRPC1 blocking antibody T1E3 and a dominant negative construct TRPC1Delta567-793. Physical interaction of TRPV4 with TRPC1 and functional role of such a complex were also found in the primary cultured rat mesenteric artery endothelial cells (MAECs) and human umbilical vein endothelial cells (HUVECs). A TRPC 1-specific siRNA was used to knock-down TRPC1 protein levels in HUVECs. Interestingly, this siRNA not only reduced the magnitude of flow-induced [Ca2+]i rise, but also accelerated the decay of flow-induced [Ca2+]i transient. Pressure myograph was used to investigate the functional role of such a complex in flow-induced vascular dilation. T1E3 also decreased flow-induced vascular dilation. Thogether, the data from endothelial cells are consistent with those in overexpressed HEK cells, supporting the notion that TRPC 1 interacts with TRPV4 to prolong the flow-induced[Ca2+]i transient, and that TRPV4-TRPC1 complex plays an important role in flow-induced vascular dilation. / In summary, my study demonstrated that TRPV4 is capable of assembling with TRPC1 to form a functional TRPV4-TRPC1 heteromeric channel. TRPV4-TRPC1 heteromeric channel can rapidly translocate to the plasma membrane after Ca 2+ depletion in intracellular stores. This TRPV4-TRPC1 heteromeric channel plays an important role in flow-induced endothelial Ca2+ influx and its associated vascular relaxation. / Ion channels are delivered to the plasma membrane via vesicle trafficking. Thus the vesicle trafficking is a key mechanism to control the amount of TRP channel proteins in the plasma membrane, where they perform their function. TRP channels in vivo are often composed of heteromeric subunits. However, up to the present, there is lack of knowledge on trafficking of heteromeric TRP channels via vesicular translocation. In the present study, we examined the effect of Ca2+ store depletion on the translocation of TRPV4-TRPC1 heteromeric channels to the plasma membrane. Experiments using total internal fluorescence reflection microscopy (TIRFM) and biotin surface labeling showed that depletion of intracellular Ca2+ stores triggered a rapid translocation of TRPV4-TRPC1 channel proteins into the plasma membrane. Fluorescent Ca2+ measurement and patch clamp studies demonstrated that store Ca2+ depletion augmented several TRPV4-TRPC1 complex-related functions, which include store-operated Ca2+ influx and cation current as well as 4alpha-PDD-stimulated Ca2+ influx and cation current. The translocation required stromal interacting molecule 1 (STIM1). Furthermore, TRPV4-TRPC1 complex is more favorably translocated to the plasma membrane than TRPC1 or TRPV4 homomers. Similar mechanisms were identified in native endothelial cells, where the TRPV4-TRPC I complex is a key component mediating flow-induced Ca2+ influx and subsequent vascular relaxation. / With the use of fluorescence resonance energy transfer (FRET), co-immunoprecipitation and subcellular colocalization methods, it was found that TRPC1 interacts physically with TRPV4 to form a heteromeric channel complex. In addition, our experimental results indicate that C-terminal and N-terminal domains of both channels are required for their interaction. / Ma, Xin. / Adviser: Yao Xiaodiang. / Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 109-121). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Kattaya-Annappa-Seema. / Thesis submitted in: December 2006. / "2+" and "+" in the title are superscripts. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 162-188). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.viii / Abstracts published based on work in this thesis --- p.ix / Table of contents --- p.x / Chapter Chapter 1: --- Introduction / Chapter 1.1 --- Pulmonary hypertension / Chapter 1.1.1 --- Pulmonary circulation and its functions --- p.1 / Chapter 1.1.2 --- Pulmonary vascular diseases and symptoms --- p.3 / Chapter 1.2 --- Muscarinic Receptor functions --- p.5 / Chapter 1.3 --- Acetylcholine (ACh) and its function --- p.7 / Chapter 1.4 --- ACh receptors in pulmonary vascular bed --- p.11 / Chapter 1.5 --- Potassium channel classification and functions --- p.12 / Chapter 1.5.1 --- "Importance of High-conductance, Ca2+ activated potassium channel (BKca) in vascular smooth muscle functions" --- p.15 / Chapter 1.5.2 --- Modulation of BKca channel by various cations --- p.18 / Chapter 1.6 --- Calcium signaling and homeostasis --- p.20 / Chapter 1.7 --- Role of sodium in hypertension --- p.22 / Chapter 1.8 --- Na+-H+ exchanger (NHE) functions --- p.25 / Chapter 1.9 --- Na+-Ca2+ exchanger (NCX) in vascular smooth muscle cells --- p.29 / Chapter 1.10 --- Spontaneously hypertensive rat (SHR) / Chapter 1.10.1 --- Hypertension in SHR --- p.32 / Chapter 1.10.2 --- BKca in smooth muscle vasculature of SHR --- p.33 / OBJECTIVES OF THE STUDY --- p.34 / Chapter Chapter 2: --- Material and methods / Chapter 2.1 --- Material / Chapter 2.1.1 --- Solutions and Drugs --- p.35 / Chapter 2.1.2 --- Chemicals and Enzymes --- p.39 / Chapter 2.2 --- Methods / Chapter 2.2.1 --- Isolation of single pulmonary arterial smooth muscle cells --- p.40 / Chapter 2.2.2 --- Electrophysiological measurement --- p.42 / Chapter 2.2.3 --- Data analysis --- p.44 / Chapter Chapter 3: --- Receptor-mediated activation of BKca Channel / Chapter 3.1 --- BKCa activation by ACh/ Carbachol (CCh) --- p.45 / Chapter 3.2 --- Role of extracellular sodium ([Na+]o）on BKca activation --- p.49 / Chapter 3.3 --- Receptor-mediated activation of BKca in a [Na+]o-containing solution --- p.51 / Chapter 3.4 --- Receptor-mediated activation of BKca in a [Na+]o-free solution --- p.55 / Chapter Chapter 4: --- Non-receptor mediated activation of BKCa Channel / Chapter 4.1 --- Effect of different concentrations of sodium nitroprusside (SNP) on BKCa activation --- p.60 / Chapter 4.2 --- Effect of SNP on BKca activation in a [Na+]o-containing and [Na+]o-free solutions --- p.62 / Chapter Chapter 5: --- Role of NHE in modulating activation of BKCa Channel / Chapter 5.1 --- Effect of Monensin on BKca activation / Chapter 5.1.1 --- Effect of monensin on CCh-mediated activation of BKca in a [Na+]o-containing solution --- p.70 / Chapter 5.1.2 --- Effect of monensin on CCh-mediated activation of BKca in a [Na+]o-free solution --- p.74 / Chapter 5.1.3 --- Effect of monensin on SNP- mediated activation of BKca in [Na+]o-containing and [Na+]o-free solutions --- p.78 / Chapter 5.2 --- Effect of 5-(N-ethyl-N-isopropyI) amiloride (EIPA) on BKCa activation / Chapter 5.2.1 --- Effect of EIPA on CCh-mediated activation of BKca in a [Na+]o-containing solution --- p.85 / Chapter 5.2.2 --- Effect of EIPA on CCh-mediated activation of BKca in a [Na+]。-free solution --- p.89 / Chapter 5.2.3 --- Effect of EIPA on SNP-mediated activation of BKCa in [Na+]o-containing and [Na+]o-free solutions --- p.93 / Chapter Chapter 6: --- Role of NCX in modulating activation of BKCa Channel / Chapter 6.1 --- Effect of KB-R7943 on CCh-mediated activation of BKCa in a [Na+]o-containing solution --- p.100 / Chapter 6.2 --- Effect of KB-R7943 on CCh-mediated activation of BKCa in a [Na+]o-free solution --- p.104 / Chapter 6.3 --- Effect of KB-R7943 on SNP-mediated activation of BKca in [Na+]o-containing and [Na+]o-free solutions --- p.109 / Chapter Chapter 7: --- Effect of intracellular sodium ([Na+]i) on BKCa channel activation / Chapter 7.1 --- Effect of CCh on BKCa channel activation with elevated [Na+]i pipette solution --- p.117 / Chapter 7.2 --- Effect of SNP on BKca channel activation with elevated [Na+]j pipette solution --- p.130 / Chapter Chapter 8: --- Discussion / Chapter 8.1 --- Modulatory effect of ACh and SNP --- p.138 / Chapter 8.2 --- Role of ion exchangers: NHE and NCX in modulating BKca channel function --- p.144 / Chapter 8.3 --- Modulatory effect of elevated [Na+]i on BKca activation --- p.153 / CONCLUSION --- p.161 / References --- p.162