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Recettori alfa adrenergici postsinaptici responsabili di vasocostrizione dell’arteria digitale comune isolata di cavallo
No full text[Nell'arteria digitale comune del cavallo sono stati studiati, in vitro, gli effetti degli agonisti e degli antagonisti alfa inf (1)- e alfa inf (2)-adrenergici, allo scopo di caratterizzare dal punto di vista funzionale gli effetti degli stimoli determinati dai recettori alfa-adrenergici postsinaptici. Contrazioni dipendenti dalla concentrazione determinate dalla fenilefrina (alfa inf (1)-agonista) venivano contrastate competitivamente sia dalla prazosina, sia dalla yohimbina, con affinita' diverse. La detomidina e l'UK14304 (alfa inf (2)-agonisti) provocavano effetti "tutto o nulla". Questi risultati fanno ipotizzare un coinvolgimento predominante degli alfa inf (1)-recettori nel controllo della contrazione del substrato mentre, al momento, non spiegano il ruolo della stimolazione degli alfa inf (1)-adrenorecettori]The effects of alpha sub (1)- and alpha sub (2)-adrenoceptor agonists and antagonists were studied in vitro on equine common digital artery to characterize functionally the effects of postjunctional alpha sub (1)- and alpha sub (2)-adrenoceptors stimulations. Concentration-dependent phenilephrine (alpha sub (1)-agonist) contractions were competitively antagonized both by prazosin and yohimbine with different affinities. Detomidine and UK14304 (alpha sub (2)-agonists) induced all or none effects. These results suggest a predominant involvement of alpha sub(1)-adrenoceptors in the contractile control of the substrate while, up to date, do not explain the role of alpha sub (2)-adrenoceptors stimulatio
Ruolo dei recettori tachichininici NK2 nella contrazione della muscolatura liscia circolare dell’ileo di cavallo
No full textRecettori adrenergici coinvolti nell’effetto vasodilatante dell’isossisuprina sull’arteria digitale comuna di cavallo.
No full textAffinity of isoxsuprine for adrenoreceptors in equine digital artery and implications for vasodilatory action
No full textWe used isolated equine digital arteries to study the vasodilatory mechanism of isoxsuprine, and fowl caecum preparations to investigate the affinity of the drug for β-adrenoceptors. Isoxsuprine is a potent vasodilator of arterial smooth muscle that has been precontracted by an α-adrenoceptor agonist such as noradrenaline (log EC50 = -6.33 [-5.98; -6.68]). The present study indicates that its effect is due to α-adrenoceptor blockade since: (1) after a long lasting exposure to cumulative doses of isoxsuprine the vasoconstricting action of noradrenaline cannot be restored; (2) isoxsuprine does not promote relaxation on preparations precontracted by PGF2α; (3) isoxsuprine shifts the dose-response curve of noradrenaline to the right; and (4) its affinity (pKB = 6.90 [6.60; 7.20]) in this experiment is comparable to that in noradrenaline-precontracted preparations and is 14 times lower than that of the selective α1-adrenergic antagonist prazosin [pKB = 8.04 (7.40; 8.68]). The affinity of isoxsuprine for β-adrenoceptors was 100 times lower than that of isoprenaline when tested on fowl caecum. This preparation has a large β-adrenoceptor and negligible α-adrenoceptor population concerned with the control of smooth muscle motility. Our data suggest that the α-mediated effect of isoxsuprine on horse arterial smooth muscle is due to higher affinity of the drug for α- than β-adrenoceptors rather than low concentration or functionality of β-sites at this site. According to these data, pure β2-agonists seem to be more profitable tools to determine vasodialtion of the arterial bed in horses legs
NK2 receptor involvement in tachykinin-induced contraction of equine ileum circular smooth muscle
No full textIdentificazione dei ß-recettori coinvolti nella lipolisi nel tessuto adiposo sottocutaneo di vitello
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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