The effects of adrenaline and the beta-agonist isoprenaline on the time course of tension reactivation were studied in several cardiac tissues. The aim of the study was to assess whether experimental evidence can be found for a role of the sarcoplasmic reticulum in the reactivation of tension. It was assumed that calcium recycles between different parts of the reticulum, and that this recycling...

The β2-adrenergic effects of macerated extract, aqueous extract, ethanol extract, and essential oil of Carum copticum, 5 nM propranolol, and saline were tested by performing cumulative Log concentration-response curves of isoprenaline-induced relaxation of precontracted isolated guinea pig tracheal chains in three different conditions including: non-incubated (group 1, n=9) incubated with 1...

Effects of isoprenaline, carbachol, and Cs+on intracellular Na+ activity ([Formula: see text]) and spontaneous action potentials were studied in multicellular and single cell preparations isolated from rabbit sinoatrial (SA) nodes.[Formula: see text] was measured with double-barreled Na+-selective microelectrodes and the fluorescent Na+-indicator sodium-binding benzofuran isophthalate (SBFI). I...

The effects of dopamine and isoprenaline on the pulmonary vasoconstrictor response to alveolar hypoxia were assessed by measuring the redistribution of blood flow between the lungs in response to unilateral hypoxia. Dose rates of dopamine 25 micrograms kg-1 min-1 and isoprenaline 0.25 micrograms kg-1 min-1 (which produced equal increments in thecontractile force of the heart in dogs) produced a...

Our previous studies have demonstrated the relaxant, anticholinergic (functional antagonism), antihistaminic, and inhibitory effect of calcium channels of Nigella sativa on guinea pig tracheal chains. To investigate the other mechanism responsible for the relaxant effect of this plant, the stimulatory effect of Nigella sativa on ß 2 -adrenergic receptors in tracheal chains of the guinea pig was...

1. In guinea-pig and canine airway smooth muscle, there is reduced beta-adrenoceptor agonist sensitivity in tissues pre-contracted with muscarinic agonists when compared to tissues pre-contracted with other spasmogens, such as histamine or leukotriene D4. This reduced sensitivity may be the result of an interaction between muscarinic receptors and beta-adrenoceptors. In this study the effects o...

The haemodynamic effects of isoprenaline were investigated in IO patients with acute myocardial infarction. Serial measurements of multiple parameters at increasing concentrations of the drug allowed establishment of a dose-response curve. Significant increase over basal values was observed in cardiac output, stroke volume, and dp/dt. Heart rate increased only moderately. Systemic and pulmonary...

Myocardial infarction is commonly considered as a leading cause of cardiovascular disease taking the lives of seven million people annually. Liver dysfunction is associated with cardiac diseases. The profile of abnormal liver functions in heart failure is not clearly defined. This study was designed to investigate the protective effects of betaine on liver injury after myocardial infarction ind...

Hysteretic behavior is found experimentally in the transmembrane potential at low extracellular potassium in mouse lumbrical muscle cells. Adding isoprenaline to the external medium eliminates the bistable, hysteretic region. The system can be modeled mathematically and understood analytically with and without isoprenaline. Inward rectifying potassium channels appear to be essential for the bis...

An obese patient was studied whose adipose tissue showed a significant reduction in release of glycerol (P < 0.05) when stimulated by isoprenaline despite normal rises in tissue levels of cyclic-AMP. However, lipolysis was stimulated by a fast of 14 days as judged by weight loss and a rise in plasma fatty acids from 0.4 to 1.2 mM. The defect in this patient may be familial since her obese daugh...