1,721,050 research outputs found
Potentiation and inhibition ofnicotinic effects on striated muscle by the tetramlne disulfide benextramineB. G. Benfey, L. Brasili, C. Melchiorre, B. Belleau
No full textln low concentratiuns the tetramlne disulfide benextramine potentiated the contracture of the isolated frog rectus abdominus muscle caused by acethilcholine but in presence of physiostigmine or in presence of higher concentration only inhibited the contracture by carbachol or butirrilcholine. The all-carbon analog of benextramine only inhibit the the effect of acetilcholine. The inhibitori effect of benextramine and it all-carbon analog were noncompèotitiveand ready reversible but the potentiating effect of benextramine was not readly reversible
MOLECULAR REQUIREMENTS OF THE ACTIVE SITESOF THE CHOLINERGIC RECEPTORSXII (*) - 3-Methyl-2-oxo-L-dimethylaminomethylcyclopentane methiodideas a new selective agonist for the nicotinic receptorM. GIANNELLA, P. ANGELI, C. MELCHIORRE, L. BRASILI
No full textTo investigate further the nature of the active sites olcholinergic reeptors the carbocyclic analogs of isomuscarone and isomuscarine were synthesized- and tested for their cholinergicactivity.Like isomuscarines, such compounds are completely devoid of muscarinic activity which further support the hypothesis that the receptor site,corresponding to position 2 of the ring, cannot accept groups larger than and/or with a dipole having a different direction from that of an etheroxygen.on the other hand nicotinic activity is quite good. In this respectcompound (IV) is particulary interesting, being as actiie as ACh and pratically devoid of muscarinic aciivity
Irreversible alfa-adrenoceptor blocking effects and irreversible muscarinic blocking and nicotinic blocking effect of tetramine disulfides on heart B. G. Benfey, B. Belleau, L. Brasili, M. Giannella, C. Melchiorre
No full textInotropic effects of phenylephrine'-carbachol' and butyryrchorine were used in rabbit reft atrium to evaluate respectively, apha receptor blocking, muscarinic blocking and nicotinic blocking effect of tetramine disulfide. The alpha adrenergic blocking potency of newly synthetized derivatives were similar to those with an o-methoxy-benzyl group. Muscarinic and nicotinic blocking potency were correlated with the alpha adrenergic blocking potency
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
Farmaci cardiaci
No full textLe patologie cardiovascolari, di cui l’insufficienza cardiaca, le varie forme di aritmia, l’angina pectoris e l’ipertensione costituiscono le più comuni, rappresentano a tutt’oggi la principale causa di mortalità nei paesi industrializzati. Fumo, obesità e stress, riconducibili ad un errato stile di vita, rappresentano rilevanti fattori di rischio, ma anche stati patologici come diabete, alterazioni del bilancio lipidico e dell’attività tiroidea possono contribuire alla loro insorgenza.
La regolazione fisiologica del sistema cardiovascolare è molto complessa e dipendente da fattori neuronali, umorali e strutturali. Inoltre, la contrattilità cardiaca stessa si verifica con un meccanismo automatico atipico rispetto alla contrazione di altri organi, e la maggior parte dei farmaci cardiaci agisce sugli eventi elettrofisiologici alla base dell’accoppiamento eccito-contrattile del cuore. Insufficienza cardiaca, aritmia e angina pectoris possono essere considerate le cardiopatie più diffuse. Il capitolo tratterà pertanto i farmaci attualmente impiegati per il trattamento di questi disturbi esaminandone meccanismo d’azione, relazioni struttura attività e procedure sintetiche
Reactivation by cysteamine of vascular alpha-adrenoceptors blocked by the tetraminedisulfide benextramine and interaction of benextramine with phenoxybenzamine
No full textThe tetramine disulfide benextramine irreversibly blocked the noradrenaline-induced contraction of the isolated rabbit aorta in a manner similar to that observed with phenoxvbenzamine. Cysteamlne abolished abolished the benextramine blockade but not the phenoxybenzamine.Incubation of aortic tissue with benextramine prior to phenoxybenzamine exposure and follwed by cysteamine treatment led to a recovery of the noradrenaline response that depended on the dose of benextramine. Thus benextramine protected alpha adrenoceptors against phenoxybenzamine blockade
Artificial neural networks and cluster analysis in landslide susceptibility zonation, Geomorphology
No full text- …
