The alpha 2A-adrenergic receptor (adrenoceptor) was stably expressed in AtT20 mouse pituitary tumor cells; adrenoceptor agonists inhibited adenylyl cyclase, inhibited voltage-dependent calcium currents, and increased inwardly rectifying potassium currents. An aspartic acid residue (Asp79) highly conserved among guanine nucleotide-binding protein (G protein)-coupled receptors was mutated to aspa...

Effect of ageing on ƒ¿1A-adrenoceptor mechanisms in rabbit bronchial preparations was studied. The potency (pD2 value) of norepinephrine increased with age from 5 to 13 weeks and thereafter did not alter with age from 13 to 180 weeks. The affinity of norepinephrine (PKA value) and of a selective ƒ¿1A-adrenoceptor blocker, 5-methylurapidil (pA2 value) did not alter with age. Efficacy of norepine...

Stressful sympathetic stimulation by cold pressor test in patients with essential hypertension results in an exaggerated response of the already elevated plasma adrenaline, heart rate, blood pressure, and alpha-adrenoceptor-mediated vasoconstriction when compared with normotensive subjects. The stress-induced increase in adrenaline was correlated with the attendant increase in blood pressure. T...

1. The aim of the study was to investigate the interactions between angiotensin II (AII) and adrenoceptor-mediated pressor responses in the pithed rat. Emphasis was placed on the effects of AII on blood pressure per se and the possibility of differential effects on alpha 1- and alpha 2-adrenoceptor-mediated pressor responses. 2. A low concentration of the angiotensin converting enzyme (ACE) inh...

β3-Adrenoceptor agonists have recently been introduced for the treatment of overactive urinary bladder syndrome. Their target, the β3-adrenoceptor, was discovered much later than β1- and β2-adrenoceptors and exhibits unique properties which make extrapolation of findings from the other two subtypes difficult and the β3-adrenoceptor a less-understood subtype. This article discusses three aspects...

BACKGROUND AND PURPOSE β(1) -, β(2) - and β(3) -adrenoceptors determined by functional, binding and reverse transcription polymerase chain reaction (RT-PCR) studies are present in chick astrocytes and activation of β(2) - or β(3) -adrenoceptors increase glucose uptake. The aims of the present study are to identify which β-adrenoceptor subtypes are present in mouse astrocytes, the signal transdu...

Guidelines for choosing drugs in chronic heart failure In a recent article, Komajda and colleagues (2005) presented data gathered from the Medical Management of Chronic Heart Failure in Europe and its Related Costs (MAHLER) survey in support of the view that adherence to guidelines in treating patients with chronic heart failure is a strong predictor of fewer cardiovascular hospitalizations in ...

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...

1 Purified membranes retaining a catecholamine responsive adenylate cyclase have been prepared from rabbit heart, lung and (pseudo-pregnant) uterus. 2 These preparations have the characteristics of plasma membranes and both heart and lung respond to P-adrenoceptor agonists in the order: (± )-isoprenaline > (-)-noradrenaline > (-)-adrenaline > ( + )-isoprenaline > salbutamol. The sensitivity of ...

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...