The ionic mechanism underlying the shortening of the action potential and the reduction in pacemaker activity by lidocaine, quinidine, and procainamide in sheep cardiac Purkinje fibers was investigated using the two-microelectrode voltage clamp technique. In the presence of lidocaine (1.85 to 3.7 x 10"M), steady state currents were shifted outward over a broad range of potentials. In contrast, ...

The ionic mechanism underlying the shortening of the action potential and the reduction in pacemaker activity by lidocaine, quinidine, and procainamide in sheep cardiac Purkinje fibers was investigated using the two-microelectrode voltage clamp technique. In the presence of lidocaine (1.85 to 3.7 x 10"M), steady state currents were shifted outward over a broad range of potentials. In contrast, ...

The inclusion of the 0-amino acid taurine or any of the nonessential amino acids glutamate, aspartate and glutamine in the perfusate, protects the heart during cardiac insults [l-41. The cardioprotective action of taurine may be related to an effect on intracellular Na' and Ca'+-mobilisation [ 11. me cardioprotective action of exogenous glutamate and aspartate has been explained in terms of inc...

The Ca storing site for the carbachol-induced contraction in a high-K medium without adding CaCl2 was further investigated in the guinea pig taenia caecum. La3+ (0.05-0.5 mM) caused an increase in peak tension and relaxation rate in the carbachol contraction but reduced or abolished the response to CaCl2. Simultaneous application of carbachol and CaCl2 produced tension development the trace of ...

The aim of this study was to investigate the effect of aerial parts of Stachys lavandulifolia Vahl. extract on the rat ileum contractions. The crude extract was prepared by maceration method (90% methanol) followed by fractionating into chloroform, ethyl acetate, petroleum ether and water. In adult male Wistar rats, ileum was sectioned and mounted in tissue bath and their contractility was reco...

Atrial fibrillation (AF) is the most common arrhythmia and associated with increased morbidity mortality. The mechanisms underlying transition from paroxysmal to persistent AF are still a matter of debate. Recent studies indicate potential role for metabolic remodelling in stabilization process levels specific substrate, succinate, have been found blood plasma patients. While succinate known in...

Loperamide, an effective antidiarrheal agent, was investigated in attempts to determine the site of action which underlies the antiperistaltic and other antidiarrheal actions. In in vitro studies, this compound applied in a dose over 10-8 g/ml, inhibited the release of both acetylcholine and prostaglandins during circumferential distension of the intestinal wall, in a dose dependent manner. The...

Action potential (AP) alternans (AP-ALT) are linked to increased arrhythmogenesis. It is suggested that calcium (Ca2+) transient (CaT) the primary cause of AP through a bi-directional coupling feedback mechanism because CaT may develop in free conditions. Supporting this notion date, counterpart scenario which absence has not yet been demonstrated. With objective developing experimental model, ...

Mechanical performance and 42K exchange were studied during anoxia in isoalted, arterially perfused, interventricular rabbit septa at 42 beats/min and 28 degree C. The septa were perfused at 1.8 ml/min per g with a modified Tyrode solution having dextrose as the metabolic substrate. Developed tension declined to 16% of preanoxic control values during 60 min of anoxia, and returned to 65% of con...

1. When rat stomach fundus muscle was incubated for 30 min in Tyrode solution from which calcium chloride had been omitted, there was an almost complete abolition of the contractile response to 5-hydroxytryptamine (5-HT) while that to acetylcholine (ACh) was still present. 2. The maximum tension obtainable with ACh remained the same in external calcium concentrations ranging from 0.45 to 3.6 mM...