Cardiac parasympathetic tone mediates hypoxic bradycardia in fish, however the specific cholinergic mechanisms underlying this response have not been established. In Chapter 2, bradycardia in zebrafish (Danio rerio) larvae experiencing translational knockdown of the M2 muscarinic receptor was either prevented or limited at two different levels of hypoxia (PO2 = 30 or 40 Torr). Also, M2 receptor deficient fish exposed to exogenous procaterol (a presumed β2-adrenergic receptor agonist) had lower heart rates than similarly treated control fish, implying that the β2-adrenergic receptor may have a cardioinhibitory role in this species. Zebrafish have a single β1-adrenergic receptor (β1AR), but express two distinct β2-adrenergic receptor genes (β2aAR and β2bAR). Zebrafish β1AR deficient larvae described in Chapter 3 had lower resting heart rates than control larvae, which conforms to the stereotypical stimulatory nature of this receptor in the vertebrate heart. However, in larvae where loss of β2a/β2bAR and β1/β2bAR function was combined, heart rate was significantly increased. This confirmed my previous observation that the β2-adrenergic receptor has an inhibitory effect on heart rate in vivo. Fish release the catecholamines epinephrine and norepinephrine (the endogenous ligands of adrenergic receptors) into the circulation when exposed to hypoxia, if sufficiently severe. Zebrafish have two genes for tyrosine hydroxylase (TH1 and TH2), the rate limiting enzyme for catecholamine synthesis, which requires molecular oxygen as a cofactor. In Chapter 4, zebrafish larvae exposed to hypoxia for 4 days exhibited increased whole body epinephrine and norepinephrine content. TH2, but not TH1, mRNA expression decreased after 2 days of hypoxic exposure. The results of this thesis provide some of the first data on receptor-specific control of heart rate in fish under normal and hypoxic conditions. It also provides the first observations that catecholamine turnover and the mRNA expression of enzymes required for catecholamine synthesis in larvae are sensitive to hypoxia. Taken together, these data provide an interesting perspective on the balance of adrenergic and cholinergic control of heart rate in zebrafish larvae.

Introduction: Across the world the incidence of the metabolic syndrome increases annually at an alarming rate. Two conditions associated with this are obesity and hypertension (high blood pressure). Both have negative health and lifestyle consequences, numerous studies on adrenergic receptor (AR) gene polymorphisms in various population groups have proved, although not exclusively, that these polymorphisms may be positively associated with susceptibility to and progression of obesity and hypertension. The AR encoding genes are attractive targets for such studies because the ARs, as part of the sympathetic nervous system, perform important functions like vasoconstriction, vasodilation, lipolysis and influence the heart's contraction. These functions accentuate the possible role of AR gene polymorphisms in the onset or progression of obesity and hypertension. Obesity is a health concern especially among black South African women. The prevalence of obesity (BMI > 30 kg/m2) in the North-West province of South Africa is high: 28.6%. The POWIRS (Profile of Obese Women with the Insulin Resistance syndrome) study was conducted in 2003 on 102 black South African female volunteers to search for possible associations of the p2-AR Gln27Glu and p3-AR Trp64Arg polymorphisms with parameters of the carbohydrate and lipid metabolism, the index of insulin resistance (HOMA-IR), body mass index (BMI) and body fat % (Schutte et al., 2005). To our knowledge, this was the first study of its kind in South Africa and which led to this study and dissertation. Objectives: The objectives of this study were to: • Determine the incidence of the following polymorphisms in (a) 102 black South African female volunteers and calculate the minor allele frequency: B1-AR: Ser49Gly; B2-AR: Arg16Gly; (b) 115 white South African female volunteers and calculate the minor allele frequency: B1-AR: Ser49Gly; B2-AR: Arg16Gly; Gln27Glu; B3-AR: Trp64Arg; • identify possible diplotypes and haplotypes in the study groups; • take relevant physiological parameters (measured in the POWIRS studies) into account in the search for possible associations of these polymorphisms, diplotypes and haplotypes with obesity and high blood pressure as characteristics of the metabolic syndrome; • compare the black and the white study groups with regards to the above mentioned objectives. Methods: DNA was isolated from blood spots on Guthrie cards (collected during the POWIRS studies) and the respective AR gene regions amplified by polymerase chain reaction (PCR). After restriction enzyme digestion, the DIVA fragments were separated by agarose gel electrophoresis. Genotypic findings were examined along with measured physiological parameters (measured during the POWIRS studies) and statistically processed. Area under the curve (AUC) analysis was performed on parameters measured during the oral glucose tolerance test. Diplotype and haplotype analyses were also performed on both subject groups. Results: The minor allele frequencies for both groups were calculated and compared to that reported in other published studies. For the black group, the minor allele frequencies were: 84% (B1-AR Ser49Gly), 16% (B2-AR Gln27Glu), 49% (B2-AR Arg16Gly) and 28% (B3-AR Trp64Arg) and for the white group: 94%, 46%, 50% and 7% respectively. The AUC differed in almost every instance of comparison, but was within normal ranges. Only a few significant differences were identified when the measured physiological parameters were compared between the genotypes, diplotypes and haplotypes in each group, most of which were found to be within normal ranges. When the two groups of test subjects were compared, only minimal differences were observed, most of which were still found to be well within normal ranges. Conclusions: Although no associations were identified between the separate investigated AR gene polymorphisms, diplotypes or haplotypes and obesity and hypertension or high blood pressure, indications are present that they may act as contributors to risk factors for the onset and progression of these characteristics of the metabolic syndrome. / Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2007.

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Class of 2012 Abstract / Specific Aims: We sought to determine the influence of genetic variation of ADRB2 on the airway response to albuterol in patients with CF when compared to matched healthy controls at baseline and at 60 minutes following the administration of albuterol (2.5mg diluted in 3ml normal saline). Methods: Baseline pulmonary function (forced vital capacity, FVC, forced expiratory flow in 1-second, FEV1, mid-maximal expiratory flow, MMF, and forced expiratory flow at 50% of the FVC) was assessed in 17 patients with CF and 31 healthy subjects. Main Results: As expected, the healthy group had higher baseline pulmonary function when compared to the CF group (FVC=97±3 vs. 83±5; FEV1=95±3 vs. 72±6; MMF=90±4 vs. 54±8, % predicted for healthy and CF, respectively, mean±SE, p<0.05 for all. We compared Arg16Arg to Arg16Gly/Gly16Gly subjects. There was no effect of genotype on the response to albuterol in healthy subjects. However, in the CF group, we found that the Arg16Arg group (n=6) had an attenuated response to β-agonist when compared to the Gly-containing group (n=11) (FVC=0±0.9 vs. 6±3: FEV1=3±1 vs. 7±4: MMF=12±3 vs. 12±5 % change, for Arg16Arg and Gly-containing groups, respectively, p<0.05 for FVC, p=0.06 for FEV1). Conclusions: These results demonstrate a differential response to β-agonists according to genetic variation of the ADRB2 at amino acid 16. Due to the differences in FVC and FEV1 but not in MMF, these data suggest that the genetic difference in airway function is primarily in bronchodilation of the larger airways.

Cardiac parasympathetic tone mediates hypoxic bradycardia in fish, however the specific cholinergic mechanisms underlying this response have not been established. In Chapter 2, bradycardia in zebrafish (Danio rerio) larvae experiencing translational knockdown of the M2 muscarinic receptor was either prevented or limited at two different levels of hypoxia (PO2 = 30 or 40 Torr). Also, M2 receptor deficient fish exposed to exogenous procaterol (a presumed β2-adrenergic receptor agonist) had lower heart rates than similarly treated control fish, implying that the β2-adrenergic receptor may have a cardioinhibitory role in this species. Zebrafish have a single β1-adrenergic receptor (β1AR), but express two distinct β2-adrenergic receptor genes (β2aAR and β2bAR). Zebrafish β1AR deficient larvae described in Chapter 3 had lower resting heart rates than control larvae, which conforms to the stereotypical stimulatory nature of this receptor in the vertebrate heart. However, in larvae where loss of β2a/β2bAR and β1/β2bAR function was combined, heart rate was significantly increased. This confirmed my previous observation that the β2-adrenergic receptor has an inhibitory effect on heart rate in vivo. Fish release the catecholamines epinephrine and norepinephrine (the endogenous ligands of adrenergic receptors) into the circulation when exposed to hypoxia, if sufficiently severe. Zebrafish have two genes for tyrosine hydroxylase (TH1 and TH2), the rate limiting enzyme for catecholamine synthesis, which requires molecular oxygen as a cofactor. In Chapter 4, zebrafish larvae exposed to hypoxia for 4 days exhibited increased whole body epinephrine and norepinephrine content. TH2, but not TH1, mRNA expression decreased after 2 days of hypoxic exposure. The results of this thesis provide some of the first data on receptor-specific control of heart rate in fish under normal and hypoxic conditions. It also provides the first observations that catecholamine turnover and the mRNA expression of enzymes required for catecholamine synthesis in larvae are sensitive to hypoxia. Taken together, these data provide an interesting perspective on the balance of adrenergic and cholinergic control of heart rate in zebrafish larvae.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23468号 / 医博第4775号 / 新制||医||1053(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 竹内 理, 教授 山下 潤, 教授 戸口田 淳也 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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No / A sensitive and rapid high performance liquid chromatography method has been developed and used for the simultaneous determination of formoterol and budesonide in Symbicort Turbuhaler when assessing the aerodynamic characteristics of the emitted dose using Pharmacopoeial methods. This capability results in both time and cost saving. The mobile phase composition was acetonitrile-5 mM sodium dihydrogen orthophosphate, pH 3 (60: 40% v/v), and was passed at 1.5 ml min-1 through a C18 column with a UV detection (wavelength 214 nm). The method was shown to give good analytical performance in terms of linearity, precision (using phenylpropanolamine as an internal standard), sensitivity and solution stability. The intra-day precision for both formoterol and budesonide were 0.75% and 1.11%, respectively (n = 10). The limit of quantitation for formoterol was 10 ¿g L-1 and for budesonide was 120 ¿g L-1, and the limit of detection were 3 and 30 ¿g L-1, for both formoterol and budesonide, respectively. The method has been applied to determine the content of the emitted dose and the fine particle dose of Symbicort Turbuhaler.

No / The electrophoretic mobilities of three beta-blocker drug practolol, timolol and propranolol, have been measured in electrolyte systems with mixed binary and ternary water-methanol-ethanol solvents with acetic acid/sodium acetate as buffer using capillary electrophoresis. The highest mobilities for the analytes studied have been observed in pure aqueous. the lowest values in ethanolic buffers The measured electrophoretic mobilities have been used to evaluate the accuracy of a mathematical model based on a mixture response surface method that expresses the mobility as a function of the solvent composition. Mean percentage error (MPE) has been computed considering experimental and calculated mobilities as an accuracy criterion. The obtained MPE for practolol, timolol and propranolol in the binary mixtures are between 0.9 and 2.6%, in the ternary water-methanol-ethanol solvent system the MPE was about 2.7%. The MPE values resulting from the proposed equation lie within the experimental relative standard deviation values and can he considered as an acceptable error.