Search results for "Tassi"
showing 10 items of 997 documents
Different mechanism of relaxation induced by aporphine alkaloids in rat uterus.
1993
Abstract We have examined the uterine relaxant action of three aporphine molecules (S-glaucine, S-boldine and R-apomorphine) in two experimental conditions, with and without calcium in the bathing solution, and compared these effects with those obtained with the calcium antagonists verapamil and diltiazem. The present study shows that the alkaloids relax the uterine muscle but with different mechanisms of action. In Ca2+-containing solution all three alkaloids relaxed the uterus previously contracted by KCl or acetylcholine, but in Ca2+-free medium only R-apomorphine was able to relax oxytocin-induced contraction. The calcium antagonists, verapamil and diltiazem, relaxed KCl- or acetylcholi…
Effects of canagliflozin on serum potassium in people with diabetes and chronic kidney disease: the CREDENCE trial
2021
Abstract Aims Hyperkalaemia is a common complication of type 2 diabetes mellitus (T2DM) and limits the optimal use of agents that block the renin–angiotensin–aldosterone system, particularly in patients with chronic kidney disease (CKD). In patients with CKD, sodium‒glucose cotransporter 2 (SGLT2) inhibitors provide cardiorenal protection, but whether they affect the risk of hyperkalaemia remains uncertain. Methods and results The CREDENCE trial randomized 4401 participants with T2DM and CKD to the SGLT2 inhibitor canagliflozin or matching placebo. In this post hoc analysis using an intention-to-treat approach, we assessed the effect of canagliflozin on a composite outcome of time to eith…
Dofetilide effects on the inhibition by trains of subthreshold conditioning stimuli.
2004
We investigated the electrophysiological actions of dofetilide upon the ventricular myocardium to determine whether the drug modifies the inhibitory effects of subthreshold stimuli trains upon ventricular refractoriness. In nine Langendorff perfused rabbit hearts, ventricular epicardial electrodes were used to determine the following parameters at baseline and during dofetilide perfusion (0.5 micromolar): effective (ERP) and functional (FRP) refractory periods, conduction velocity (CV), wavelength (WL), and ERP prolongation (inhibitory effect) induced by subthreshold stimuli trains (STr) at pulse frequencies of 100, 300, and 600 Hz. Dofetilide significantly prolongs ventricular refractorine…
Immunohistochemical analysis of KCNQ3 potassium channels in mouse brain.
2005
KCNQ-type potassium channels generate the so-called M-current regulating excitability in many neurons. Mutations in KCNQ2/KCNQ3 channels can cause benign familial neonatal convulsions (BFNC). We describe the immunohistochemical staining of adult and developing mouse brain using an antibody directed against the N-terminus of KCNQ3 channels (KCNQ3N). A widespread KCNQ3N immunoreactivity predominantly of neuropil but also of somata was detected in different regions of the adult mouse brain, in particular in the hippocampus, cortex, thalamus and cerebellum. This staining pattern appeared gradually and became more intense during development. In the pyramidal cell layer of the hippocampus, the im…
Pharmacological investigation into the effects of histamine and histamine analogues on guinea-pig and rat colon in vitro.
1986
The effects of histamine and specific histamine agonists has been examined on isolated longitudinal colon strips of guinea-pig and rat. Histamine and 2-pyridyl-ethylamine but not 4 methylhistamine produced a concentration-related contractile response in the guinea-pig colon. The H1-antagonist clemizole antagonized competitively the effect of histamine but the H2-antagonist ranitidine did not modify the dose-response curve to histamine in the guinea-pig colon. Atropine, hexamethonium, prazosin and propranolol failed to modify the contractile response to histamine. Tone induced with KCl in guinea-pig isolated colon was not modified by histamine agonists even in tissues pretreated with clemizo…
Effect of the stable prostacyclin analogue iloprost on water and electrolyte transfer of the rat ileum and colon in vivo.
1988
The effect of iloprost on water and ion transfer was measured simultaneously in tied-off loops of the rat ileum and colon in vivo. (1) In the ileal loops iloprost had no effect on water and ion transfer neither by intraluminal, nor intraaortal or intravenous application. (2) In the colonic loops only intraaortal bolus application of the high dose of 500 micrograms iloprost significantly decreased net water, sodium and chloride absorption, but did not induce net secretion. (3) Inhibition of endogenous prostaglandin synthesis by indomethacin did not change net water and electrolyte transfer in the ileum and colon. (4) Under this pretreatment i.v.-application of 100 micrograms iloprost, ineffe…
Intestinal filtration as a consequence of increased mucosal hydraulic permeability
1980
Two mechanisms have been proposed to explain the secretory action of laxative compounds in the intestine: 1. increase of the intracellular amount of cyclic adenosine monophosphate due to stimulation of the adenylate cyclase system and 2. inhibition of intestinal transfer processes, in particular the Na,K-ATPase activated sodium absorption. In a set of in vivo and in vitro experiments in rat colon it could be demonstrated that dihydroxy bile acids (deoxycholate) and diphenolic laxatives (oxyphenisatin) enhance the hydraulic permeability of the mucosal tissue. The permeability changes take place--and there is good experimental evidence--at the zonulae occludentes which bind the epithelial cel…
Adenosine activates a potassium conductance in guinea-pig atrial heart muscle.
1983
Adenosine shortens the action potential and diminishes the force of contraction in guinea-pig left atria. These effects may be brought about by the activation of a potassium conductance. This assumption is supported by voltage clamp and 42K release experiments.
Relaxation by Calcium Antagonists of Potassium-contracted Trachea from Normal and Sensitized Guinea-pigs: Influence of Epithelium and the Surface of …
1993
Abstract A technique by which drug access was restricted to either the mucosal or the adventitial surface of tracheal rings, isolated from normal (unsensitized) or sensitized guinea-pigs, was used to study the role of the epithelium in the relaxation produced by calcium antagonists (verapamil, nifedipine, cinnarizine and flunarizine) of K+-induced contraction. In trachea from normal guinea-pigs, the relaxation to verapamil for unrestricted or mucosal drug entry was reduced in the absence of epithelium, whereas the relaxation produced by nifedipine, cinnarizine or flunarizine was unchanged. In sensitized trachea, the relaxation elicited by the calcium antagonists tested was similar in intact…
Effects of Mn2+ on the responses induced by different spasmogens in the oestrogen-primed rat uterus
1997
Abstract We investigated the effect of Mn 2+ on the mechanical responses evoked by high K + (60 mM) or low Na + (25 mM) solutions, oxytocin and neurokinin A in the oestrogen-primed rat uterus. In a Ca 2+ -free, Mn 2+ (0.54 mM)-containing solution, high K + or low Na + solutions produced contractions of smaller amplitude than those observed in a normal Ca 2+ (0.54 mM) solution, which were abolished by nifedipine (1 μM). Oxytocin (1 μM) and neurokinin A (1 μM, in the presence of phosphoramidon 1 μM) evoked nifedipine-insensitive contractile responses similar to (oxytocin) or smaller (neurokinin A) in amplitude than those observed in Ca 2+ (0.54 mM)-containing solution. In strips loaded with C…