Biomaterial Database

Evidence for cardiac beta 2-adrenoceptors in man. 1983

J E Brown, and A A McLeod, and D G Shand

We compared the effects of single doses of 50 mg atenolol (cardioselective), 40 mg propranolol (nonselective), and placebo on both exercise- and isoproterenol-induced tachycardia in two experiments involving nine normal subjects. Maximal exercise heart rate was reduced from 187 +/- 4(SEM) after placebo to 146 +/- 7 bpm after atenolol and 138 +/- 6 bpm after propranolol, but there were no differences between the drugs. The effects on isoproterenol tachycardia were determined before and after atropine (0.04 mg/kg IV). Isoproterenol sensitivity was determined as the intravenous dose that increased heart rate by 25 bpm (CD25) and this was increased from 1.8 +/- 0.3 micrograms after placebo to 38.9 +/- 8.3 micrograms after propranolol and 8.3 +/- 1.7 micrograms after atenolol. The difference in the effects of the two was significant. After atropine the CD25 was unchanged after placebo (2.3 +/- 0.3 micrograms) and atenolol (7.7 +/- 1.3 micrograms); it was reduced after propranolol (24.8 +/- 5.0 micrograms), but remained different from atenolol. This change with propranolol sensitivity was calculated as the apparent Ka, this was unchanged by atropine (11.7 +/- 2.1 and 10.1 +/- 2.5 ml/ng). These data are consistent with the hypothesis that exercise-induced tachycardia results largely from beta 1-receptor activation that is blocked by both cardioselective and nonselective drugs, whereas isoproterenol activates both beta 1- and beta 2-receptors so that after cardioselective blockade there remains a beta 2-component that can be blocked with a nonselective drug. While there appear to be beta 2-receptors in the human heart, their physiologic or pathologic roles remain to be defined.

UI	MeSH Term	Description	Entries
D007545	Isoproterenol	Isopropyl analog of EPINEPHRINE; beta-sympathomimetic that acts on the heart, bronchi, skeletal muscle, alimentary tract, etc. It is used mainly as bronchodilator and heart stimulant.	Isoprenaline,Isopropylarterenol,4-(1-Hydroxy-2-((1-methylethyl)amino)ethyl)-1,2-benzenediol,Euspiran,Isadrin,Isadrine,Isopropyl Noradrenaline,Isopropylnoradrenaline,Isopropylnorepinephrine,Isoproterenol Hydrochloride,Isoproterenol Sulfate,Isuprel,Izadrin,Norisodrine,Novodrin,Hydrochloride, Isoproterenol,Noradrenaline, Isopropyl,Sulfate, Isoproterenol
D008297	Male		Males
D011412	Propanolamines	AMINO ALCOHOLS containing the propanolamine (NH2CH2CHOHCH2) group and its derivatives.	Aminopropanols
D011433	Propranolol	A widely used non-cardioselective beta-adrenergic antagonist. Propranolol has been used for MYOCARDIAL INFARCTION; ARRHYTHMIA; ANGINA PECTORIS; HYPERTENSION; HYPERTHYROIDISM; MIGRAINE; PHEOCHROMOCYTOMA; and ANXIETY but adverse effects instigate replacement by newer drugs.	Dexpropranolol,AY-20694,Anaprilin,Anapriline,Avlocardyl,Betadren,Dociton,Inderal,Obsidan,Obzidan,Propanolol,Propranolol Hydrochloride,Rexigen,AY 20694,AY20694,Hydrochloride, Propranolol
D011897	Random Allocation	A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.	Randomization,Allocation, Random
D011941	Receptors, Adrenergic	Cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. The two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. Adrenergic receptors may also be classified according to the subtypes of G-proteins with which they bind; this scheme does not respect the alpha-beta distinction.	Adrenergic Receptors,Adrenoceptor,Adrenoceptors,Norepinephrine Receptor,Receptors, Epinephrine,Receptors, Norepinephrine,Adrenergic Receptor,Epinephrine Receptors,Norepinephrine Receptors,Receptor, Adrenergic,Receptor, Norepinephrine
D011943	Receptors, Adrenergic, beta	One of two major pharmacologically defined classes of adrenergic receptors. The beta adrenergic receptors play an important role in regulating CARDIAC MUSCLE contraction, SMOOTH MUSCLE relaxation, and GLYCOGENOLYSIS.	Adrenergic beta-Receptor,Adrenergic beta-Receptors,Receptors, beta-Adrenergic,beta Adrenergic Receptor,beta-Adrenergic Receptor,beta-Adrenergic Receptors,Receptor, Adrenergic, beta,Adrenergic Receptor, beta,Adrenergic beta Receptor,Adrenergic beta Receptors,Receptor, beta Adrenergic,Receptor, beta-Adrenergic,Receptors, beta Adrenergic,beta Adrenergic Receptors,beta-Receptor, Adrenergic,beta-Receptors, Adrenergic
D004311	Double-Blind Method	A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.	Double-Masked Study,Double-Blind Study,Double-Masked Method,Double Blind Method,Double Blind Study,Double Masked Method,Double Masked Study,Double-Blind Methods,Double-Blind Studies,Double-Masked Methods,Double-Masked Studies,Method, Double-Blind,Method, Double-Masked,Methods, Double-Blind,Methods, Double-Masked,Studies, Double-Blind,Studies, Double-Masked,Study, Double-Blind,Study, Double-Masked
D004562	Electrocardiography	Recording of the moment-to-moment electromotive forces of the HEART as projected onto various sites on the body's surface, delineated as a scalar function of time. The recording is monitored by a tracing on slow moving chart paper or by observing it on a cardioscope, which is a CATHODE RAY TUBE DISPLAY.	12-Lead ECG,12-Lead EKG,12-Lead Electrocardiography,Cardiography,ECG,EKG,Electrocardiogram,Electrocardiograph,12 Lead ECG,12 Lead EKG,12 Lead Electrocardiography,12-Lead ECGs,12-Lead EKGs,12-Lead Electrocardiographies,Cardiographies,ECG, 12-Lead,EKG, 12-Lead,Electrocardiograms,Electrocardiographies, 12-Lead,Electrocardiographs,Electrocardiography, 12-Lead
D005082	Physical Exertion	Expenditure of energy during PHYSICAL ACTIVITY. Intensity of exertion may be measured by rate of OXYGEN CONSUMPTION; HEAT produced, or HEART RATE. Perceived exertion, a psychological measure of exertion, is included.	Physical Effort,Effort, Physical,Efforts, Physical,Exertion, Physical,Exertions, Physical,Physical Efforts,Physical Exertions