A protocol is presented for supine bicycle ergometry in healthy subjects, which aims for a target increase of heart rate (HR = 140 beats min-1) after 4 min cycling under constant load. The required load is selected from a pre-study ergometry with stepwise increasing load. Repeated testing with this protocol was shown to yield highly reproducible ergometric HR-responses. Because of their high re...

β-Adrenoceptor antagonists boast a 50-year use for symptomatic control in numerous cardiovascular diseases. One might expect highly selective antagonists are available for the human βadrenoceptor subtype involved in these diseases, yet few truly β1-selective molecules exist. To address this clinical need, we re-evaluated LK 204-545 (1), a selective β1-adrenoceptor antagonist, and discovered it ...

BACKGROUND Takotsubo cardiomyopathy (TCM) is characterized by regional left ventricular dysfunction that cannot be explained by an occlusive lesion in a coronary artery. Catecholamines are implicated in the pathogenesis of TCM but the mechanisms involved are unknown. Because the endogenous and the most commonly used exogenous catecholamines have well defined adrenoceptor subtype affinities, inf...

We examined the contribution of large-conductance, Ca(2+)-sensitive K+ (MaxiK) channel to beta2-adrenoceptor-activated relaxation to isoprenaline in guinea-pig tracheal smooth muscle focusing on the role for cAMP in the coupling between beta2-adrenoceptor and MaxiK channel. Isoprenaline-elicited relaxation was confirmed to be mediated through beta2-type of adrenoceptor since the response was an...

AIMS β2-adrenergic stimulation causes beneficial effects on structure and function of regenerating muscles; thus, the β2-adrenoceptor may play an important role in the muscle regenerative process. Here, we investigated the role of the β2 -adrenoceptor in skeletal muscle regeneration. METHODS Tibialis anterior (TA) muscles from β2-adrenoceptor knockout (β2 KO) mice were cryolesioned and analys...

a2C adrenoceptors occur in high density in the striatum, but the functional role of these receptors is uncertain. Mice with targeted inactivation of the a2C adrenoceptor gene (Adra2c ) and genetically related control mice expressing the wild-type a2C adrenoceptor (Adra2c ) were used to determine whether striatal a2C adrenoceptors modulate adenylyl cyclase activation. In striatal slices from Adr...

BACKGROUND/AIMS Renalase is a recently discovered, kidney-specific monoamine oxidase that metabolizes circulating catecholamines. These findings present new insights into hypertension and chronic kidney diseases. Previous data demonstrated that renalase was mainly secreted from proximal tubules which could be evoked by catecholamines. The purpose of this study is to investigate whether renalase...

Catecholamine-induced lipolysis in isolated human adipocytes during the first year of life was investigated. During this period fat cell size increased markedly. Basal and catecholamine-induced glycerol release were positively correlated with age when lipolysis was expressed per cell. However, when lipolysis was expressed per unit of cell surface area (micrometer squared), this correlation was ...

The hyperkalaemic action of adrenaline was investigated in 44 anaesthetized domestic pigs. Plasma and epicardial concentrations of K were measured, in the latter case with an ion-selective electrode. Adrenaline 10 pgkg~ caused a rapid increase in the plasma concentration of K from 4.2 to 5.9 mmol litre'. The magnitude and the time course of epicardial concentration of K were similar. Alpha-adre...

Cardiac α1-adrenoceptor stimulation elicits a positive inotropic effect because of myofilament Ca2+ sensitization with a small increase in Ca2+ transients predominantly mediated by α1B-adrenoceptors via the intracellular alkalinization and potential myosin light chain 2 phosphorylation. However, the α1-adrenoceptor– mediated inotropy exhibits a wide range of species-dependent variation. In addi...