Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2008. / Vita. Includes bibliographical references.

Thesis (doctoral)--Katholieke Universiteit te Nijmegen.

Kai Hong Kwok. / Thesis submitted in: December 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 90-98). / Abstract also in Chinese. / Chapter Chapter 1 --- Introduction / Chapter 1.1. --- Classification of β-adrenoceptor in cardiovascular system --- p.1 / Chapter 1.2. --- Vasodilator effects of β-adrenoceptor-agonists and their mechanisms --- p.4 / Chapter 1.3. --- Role of endothelium in β-adrenoceptor-mediated vasodilation --- p.7 / Chapter 1.4. --- Role of K+ channels in β-adrenoceptor-mediated relaxation --- p.11 / Chapter 1.5. --- Other aspect regarding the vascular response to stimulation of B-adrenoceptor --- p.15 / Chapter 1.6. --- Clinical aspect of B-adrenoceptor agents --- p.15 / Chapter Chapter 2 --- Methods and Materials / Chapter 2.1. --- Tissue Preparation --- p.19 / Chapter 2.1.1. --- Preparation of the isolated rat mesenteric artery --- p.19 / Chapter 2.1.2. --- Removal of the functional endothelium --- p.19 / Chapter 2.1.3. --- Organ bath set-up --- p.20 / Chapter 2.1.4. --- Length-tension relationship and an optimal resting tension --- p.22 / Chapter 2.2. --- Experimental Procedure --- p.22 / Chapter 2.2.1. --- Relaxant effects of the B-adrenoceptor agonists --- p.24 / Chapter 2.2.2. --- Effects of putative K+ channel blockers --- p.24 / Chapter 2.2.3. --- Effects of inhibitors of nitric oxide activity --- p.25 / Chapter 2.2.4. --- Effect of indomethacin --- p.25 / Chapter 2.2.5. --- "Effects of K+ channel opener, nitric oxide donor and forskolin" --- p.26 / Chapter 2.3. --- Chemicals and Solutions --- p.26 / Chapter 2.3.1. --- Chemicals and drugs --- p.26 / Chapter 2.3.2. --- Preparation of drug stock solutions --- p.26 / Chapter 2.3.3. --- Solutions --- p.28 / Chapter 2.4. --- Statistical Analysis --- p.28 / Chapter Chapter 3 --- Results / Chapter 3.1. --- Relaxant Effect of Isoprenaline --- p.29 / Chapter 3.1.1. --- Relaxant effect of isoprenaline --- p.29 / Chapter 3.1.2. --- Effects of inhibitors of nitric oxide activity --- p.29 / Chapter 3.1.3. --- Effect of charybdotoxin on the vasorelaxant response to isoprenaline --- p.32 / Chapter 3.1.4. --- Effect of glibenclamide on the vasorelaxant response to isoprenaline --- p.32 / Chapter 3.1.5. --- Effect of TPA+ on isoprenaline-induced relaxation --- p.36 / Chapter 3.1.6. --- Effect of TPA+ in the presence of iberiotoxin or glibenclamide --- p.36 / Chapter 3.1.7. --- Effect of Ba2+ on the vasorelaxant effect of isoprenaline --- p.41 / Chapter 3.1.8. --- Effect of raising extracellular K+ on isoprenaline-mediated relaxation --- p.41 / Chapter 3.2. --- Relaxant Effect of Dobutamine --- p.44 / Chapter 3.2.1. --- Effects of inhibitors of endothelium-derived factors on the relaxant effect of dobutamine --- p.44 / Chapter 3.2.2. --- Antagonism of the effect of dobutamine by β1-adrenoceptor antagonist --- p.44 / Chapter 3.2.3. --- Effects of putative Kca channel blockers on the relaxant effect of dobutamine --- p.51 / Chapter 3.2.4. --- Effect of TPA+ on the relaxant effect of dobutamine --- p.55 / Chapter 3.2.5. --- Effect of raising extracellular K+ on the relaxant effect of dobutamine --- p.55 / Chapter 3.3. --- Relaxant Effect of Fenoterol --- p.57 / Chapter 3.3.1. --- Effect of inhibitors of nitric oxide activity on the relaxant effect of fenoterol --- p.57 / Chapter 3.3.2. --- Effect of charybdotoxin on the relaxant effect of fenoterol --- p.57 / Chapter 3.3.3. --- Effect of TPA+ on the relaxant effect of fenoterol --- p.64 / Chapter 3.3.4. --- Effect of glibenclamide on the relaxant effect of fenoterol --- p.64 / Chapter 3.3.5. --- Effect of raising extracellular K+ on fenoterol-mediated relaxation --- p.64 / Chapter 3.4. --- Effects of cAMP- and cGMP-elevating agents --- p.69 / Chapter 3.4.1. --- Effects of inhibitors of endothelium-derived factors on the relaxation induced by nitroprusside and forskolin --- p.69 / Chapter 3.4.2 --- Effect of charybdotoxin on relaxant effect of forskolin --- p.69 / Chapter 3.4.3 --- Effect of Ba2+ on the vasorelaxant effect of forskolin --- p.76 / Chapter 3.4.4 --- Effect of TPA+ on the relaxant effect of forskolin --- p.76 / Chapter 3.4.5 --- Effect of glibenclamide on the relaxant effects of forskolin and cromakalim --- p.76 / Chapter Chapter 4 --- Discussion / Chapter 4.1. --- Effect of Isoprenaline and Fenoterol --- p.77 / Chapter 4.2. --- Effect of Dobutamine --- p.83 / Chapter 4.3. --- Conclusion --- p.88 / References --- p.90 / Publications --- p.98

Thesis (Ph. D.)--University of Virginia, 1998. / Neurobiology of alpha-2 receptors. Includes bibliographical references. Also available online through Digital Dissertations.

The chronotropic and inotropic responses to isoprenaline and salbutamol were determined in the chloralose anaesthetized dog. The myocardium was denervated, sympathetically and parasympathetically to prevent direct neural influence on the heart rate and myocardial contractility. The heart rate was determined from the E.C.G. Myocardial contractility was indicated by the change in the maximum rate of rise of left ventricular pressure (dP/dt max) at a constant electrically paced heart rate. The structure-activity relationships for salbutamol and isoprenaline were determined from dose-response curves and by plotting the change in contractility (ΔdP/dt max) against the change in heart rate (ΔHR). The data obtained from this series of experiments indicated that the only difference between the effects of the agonists on the inotropic and chronotropic responses of the myocardium was the lower affinity of salbutamol for the adrenergic receptor as indicated by the 100 times greater concentration required to produce the same response level. Previously reported in vitro studies with the guinea pig atrium and dog papillary muscle had indicated that a smaller inotropic response to salbutamol should have been expected. To test this discrepancy between the present in vivo experimentation, and the previous in vitro work, studies were designed to test the guinea pig atrium and the dog papillary muscle in vitro. The effects of the agonists were studied on the isolated guinea pig atrium in a manner that paralleled the in vivo dog study. With the organ bath at 25°C, the chronotropic response, measured by the change in free contraction rate (ΔR), and the inotropic response, determined from the change in peak tension developed (ΔT) during electrical stimulation at 2 Hz, to a single randomly ordered dose of salbutamol or isoprenaline were determined. Salbutamol acted as a partial agonist, that is, had a lower efficacy than isoprenaline. However, the relative effect of each drug on the inotropic and chronotropic responses was almost identical. In the isolated dog papillary muscle, salbutamol displayed a much lower efficacy, producing only 20% of the maximum isoprenaline increase in peak tension developed to the cummulative addition of agonist. The affinity of salbutamol for the adrenergic receptor in this preparation was much lower than that observed in vivo when compared with isoprenaline, 5,000:1 and 100:1 respectively. The structure-activity relationships for salbutamol and isoprenaline showed that the relative effects of these agonists on the in vivo denervated dog myocardial inotropic and chronotropic responses were similar. This observation indicates that the adrenergic receptors of the dog myocardium mediating the inotropic and chronotropic responses are structurally similar at a site complementary to the phenyl ring of the agonist molecule. However,, a definite conclusion regarding the adrenergic receptors responsible for the inotropic response cannot be made because of the unexplained difference in inotropic response observed with ventricular muscle in vivo and in vitro. Examination of the structure-activity relationships for salbutamol and isoprenaline in the in vitro guinea pig atrium indicates that, in this preparation also, the adrenergic receptors involved in the two measured responses are probably structurally similar. / Medicine, Faculty of / Cellular and Physiological Sciences, Department of / Graduate

This thesis records a series of experiments conducted to gain further insight into factors which influence the expression, ligand binding and functional activity of the beta-2 adrenergic receptor. These studies were prompted by previous reports that the postulated beta-2 adrenergic receptor abnormality in allergic asthma could be induced, induced by autoantibodies. I established and optimised beta-2 adrenergic receptor ligand binding and functional assays in guinea pig lung membranes and then conducted an original study of beta adrenergic receptor expression in the guinea pig foetal lung. I found that beta adrenergic receptor expression in the foetal lung was dormant for 80% of the gestation period. After day 53 there was a surge in receptor expression which increased beyond term.

by Lo Ping Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1987. / Includes bibliographical references.

G protein coupled receptors, G proteins and their downstream effectors adenylyl cyclase (ACs) were thought to transiently interact at the plasma membrane by random collisions following agonist stimulation. However a growing number of studies have suggested that a major revision of this paradigm was necessary to account for signal transduction specificity and efficiency. The revised model suggests that signalling proteins are pre-assembled as stable macromolecular complexes together with modulators of their activity prior to receptor activation. How and where these signalling complexes form and the mechanisms governing their assembly and maintenance are not completely understood yet. Initially, we addressed this question by exploring AC2 interaction with beta2-adrenergic receptors (beta2ARs) and heterotrimeric G proteins as parts of a pre-assembled signalling complex. Using a combination of biophysical and biochemical techniques, we showed that AC2 interacts with them before it is trafficked to the cell surface in transfected HEK-293 cells. These interactions are constitutive and do not require stimulation by receptor agonists. Furthermore, the use of dominant-negative Rab/Sar monomeric GTPases and dominant-negative heterotrimeric G protein subunits proved that AC2/beta2AR and AC2/Gbetagamma interactions occurred in the ER as measured using both BRET and co-immunoprecipitation experiments, while interaction of the Galpha subunits with the above complexes occurred at a slightly later stage. Both Galpha and Gbetagamma played a role in stabilizing these complexes. Our data also demonstrated that stimulation of AC was still possible when the complex remained on the inside of the cell but was reduced when the GalphaS/AC2 interaction was blocked, suggesting that the addition of the GalphaS subunit was required to render the nascent complexes functional prior to trafficking to proper sites of action. Next, we tackled the issue of higher order assembly of effectors and G proteins, using two different AC isoforms and GalphaS as a model. We demonstrated that AC2 can form heterodimers with AC5 through direct molecular interaction in unstimulated HEK-293 cells. AC2/5 heterodimerization resulted in a reduced total level of AC2 expression, which affected cellular accumulation of cAMP upon forskolin stimulation. The AC2/5 complex was stable in presence of receptor or forskolin stimulation. We provided evidence that co-expression with GalphaS increased the affinity of AC2 for AC5 as monitored by BRET. In particular, the complex formed by AC2/5 lead to synergistic accumulation of cAMP in presence of GalphaS and forskolin, with respect to either of the parent AC isoforms themselves. Finally, we also showed that this complex can be detected in native tissues, as AC2 and AC5 could be co-immunoprecipiated from lysates of mouse heart. Taken together, we provided evidence for stable formation of signalling complexes involving receptor/G proteins/adenylyl cyclase or G proteins/heterodimeric adenylyl cyclases and that G proteins play a crucial role for their assembly and function.

Thesis (M.Sc.). / Written for the Dept. of Neurology and Neurosurgery. Title from title page of PDF (viewed 2008/05/14). Includes bibliographical references.

Thesis (doctoral)--Umeå Universitet, Sweden, 1991. / Extra t.p. with thesis statement inserted. Includes bibliographical references.