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Importância. Anticoncepcionais hormonais combinados orais (AHCO) podem levar ao aumento do risco da doença cardiovascular, que pode estar associado a alterações na pressão arterial e na função endotelial. Objetivos. O objetivo deste estudo foi avaliar o impacto do uso de AHCO contendo 20 mg de etinilestradiol (EE) e 3 mg de drospirenona (DRSP) por mulheres jovens normotensas sobre a função endotelial arterial, pressão arterial sistólica (PAS, mmHg) e diástólica (PAD, mmHg), frequência cardíaca (FC, bpm), débito cardíaco (DC, L/min), e sobre a resistência periférica total (RPT, NU). Métodos. Setenta e uma mulheres jovens saudáveis com idade média de 29 ± 1 ano foram avaliadas. Quarenta e três foram analisadas antes da introdução do AHCO e ao final de 6 meses de uso (grupo-caso) e vinte e oito, não usuárias de nenhum método hormonal de contracepção, foram avaliadas quanto aos mesmos parâmetros no mesmo intervalo de tempo (grupo-controle). Resultados. Não se observaram mudanças significantes na função endotélio-dependente (VMF%) e independente (VIE%) e nas medidas de PAS, PAD, FC, DC e da RPT com o uso do AHCO (p> 0,05 para todas as variáveis). Não houve variações significantes nestes parâmetros no grupo-controle. Conclusão: O uso desta formulação de AHCO não causou alterações deletérias na reatividade vascular, e nas variáveis hemodinâmicas em mulheres jovens normotensas. / Background: Combined oral contraceptives (COCs) may lead to a rise in cardiovascular disease risk, possibly associated with changes in blood pressure and endothelial function. Objective: The objective was to evaluate the impact of COC containing 20 mcg of ethinyl estradiol (EE) and 3 mg of drospirenone (DRSP) on the arterial endothelial function, systolic and diastolic blood pressure (SBP and DBP), heart rate (HR), cardiac output (CO), and total peripheral resistance (TPR) of normotensive young women. Methods: Of the 71 women in the study, 43 were evaluated before the introduction of COC and after 6 months of its use (case group) and 28, COC nonusers, were assessed for the same parameters at the same time interval (control group). Results: No significant changes in endothelium-dependent and -independent functions or in measures of SBP, DBP, HR, CO, and TPR caused by COC use were observed in the case group (P> 0.05 for all variables) or in the control group. Conclusion: These data suggest COC with 20 mcg EE and 3 mg DRSP does not alter arterial endothelial function or hemodynamic parameters in normotensive young women

Cyclic nucleotide-gated (CNG) ion channels are Ca2+ permeable nonselective cation channels that are directly gated by binding of cAMP or cGMP, thus providing a linkage between two important signal molecules, cyclic nucleotides and calcium. They are known to play an important role in sensory transduction and in second-messenger modulation of synaptic neurotransmitter release. Previous studies showed that besides in neuronal cells, CNG were found also in non-neuronal tissues including heart, kidney, blood vessels and spleen, they are reported to be involved in a variety of cell function. / Ion channels play an indispensable role in endothelial cells, which is a unique signal-transducting surface in the vascular system that is responsible in altering vascular tone. The present study investigated the expression and functional roles of the cyclic nucleotide gated channels (CNG) in regulating the intracellular calcium level of vascular endothelial cells using molecular and calcium measurement techniques. / The present study provided evidence that the CNG channels, especially that of CNGA2, were expressed in vascular tissues. I used a variety of different methods, including RT-PCR, northern blot, in-situ hybridization, immunohistochemistry and western blot to study the localization of CNGA2 channels. RT-PCR amplify a CNGA2 fragment of 582bp from RNAs isolated from bovine vascular endothelial cell line, rat vascular smooth muscle cell line and rat aorta. Northern blot analysis detected a 2.3-kilobase (kb) CNGA2 transcript in rat aorta mRNA. The cellular distribution of CNGA2 was further studied by in-situ hybridization, which demonstrated expression of CNGA2 mRNA in human vascular endothelial and vascular smooth muscle cells. Immunohistochemistry data also agreed with those generated from in-situ hybridization. Western blot data also demonstrated proteins of CNG2 was expressed in both human vascular endothelial cells and vascular smooth cells layer. Subcellular localization of CNGA2 inside the vascular endothelial cells was also investigated with the use of a GFP linked CNGA2 channel gene. Taken together, the results showed that CNGA2 proteins were expressed on the plasma membrane of the vascular endothelial cells. (Abstract shortened by UMI.) / Cheng Kwong Tai Oscar. / "July 2005." / Adviser: Xiaoqiang Yao. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3531. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 216-243). / 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, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.