No abstract

Androgens may exert cardiovascular protective actions by regulating the release and function of different vascular factors. In addition, testosterone (TES) and its 5-reduced metabolites, 5α- and 5β-dihydrotestosterone (5α- and 5β-DHT) induce vasorelaxant and hypotensive effects. Furthermore, hypertension has been reported to alter the release and function of the neurotransmitters nitric oxide (NO), calcitonin gene-related peptide (CGRP) and noradrenaline (NA). Since the mesenteric arteries possess a dense perivascular innervation and significantly regulate total peripheral vascular resistance, the objective of this study was to analyze the effect of TES, 5α- and 5β-DHT on the neurogenic release and vasomotor function of NO, CGRP and NA. For this purpose, the superior mesenteric artery from male spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto (WKY) rats was used to analyze: (i) the effect of androgens (10 nM, incubated for 30 min) on the neurogenic release of NO, CGRP and NA and (ii) the vasoconstrictor-response to NA and the vasodilator responses to the NO donor, sodium nitroprusside (SNP) and exogenous CGRP. The results showed that TES, 5α- or 5β-DHT did not modify the release of NO, CGRP or NA induced by electrical field stimulation (EFS) in the arteries of SHR; however, in the arteries of WKY rats androgens only caused an increase in EFS-induced NO release. Moreover, TES, and especially 5β-DHT, increased the vasodilator response induced by SNP and CGRP in the arteries of SHR. These findings could be contributing to the hypotensive/antihypertensive efficacy of 5β-DHT previously described in conscious SHR and WKY rats, pointing to 5β- DHT as a potential drug for the treatment of hypertension.

Using Griem’s semi-empirical approach, we have calculated the Stark broadening parameters (line widths and shifts) of 35 UV–Blue spectral lines of neutral vanadium (V I). These lines have been detected in the Sun, the metal-poor star HD 84937, and Arcturus, among others. In addition, these parameters are also relevant in industrial and laboratory plasma. The matrix elements required were obtained using the relativistic Hartree–Fock (HFR) method implemented in Cowan’s code.

In this work, the Stark broadening parameters (linewidths and shifts) of 114 visible- infrared spectral lines of neutral vanadium (V I) have been calculated. As in a previous work devoted to their spectral lines in the UV-blue range, these parameters have been calculated using the Griem’s semiempirical formula and the Cowan code for the calculation of the necessary matrix elements. In addition to their astrophysical interest (the majority of the analysed spectral lines have been detected in Arcturus, in the metal-poor star HD 84937 and in the Sun), these parameters are also relevant in the analysis of plasmas generated in industrial processes in LSP treatments of Ti-6Al-4V type samples.

Recently, in 2020, Stark broadening parameters have been measured for spectral lines belonging to 75 Vanadium II multiplets. For some of them there are published calculations in the literature. However, these lines are not sufficient for the analysis of the lines present in the metal-poor star HD 8493. When new calculations by the Griem approximation are performed and compared with the experimental results, in some cases there is a difference of a factor of 7. It is clear that the problem lies, as already suggested some years ago in a theoretical paper by Douglas H. Sampson, in the poor approximation proposed by Van Regemorter for the Gaunt factors used in the Griem approximation. In this work we have performed broadening measurements of 3276.12 Å and 3715.46 Å V ii lines which confirmed the previous measurements of 2020. Subsequently, we performed a more accurate calculation using the procedure to calculate the Gaunt factors suggested by Sampson , obtaining results very close to the experimental values. These allowed us to assume that the calculations performed for 56 lines ranging between 3700-4600 Å (present in the photospheres of the Sun and the metal-poor star HD 8493), and without experimental information, they are more accurate using the Gaunt factors proposed by Sampson.