beta. -Adrenoceptors in human tracheal smooth muscle: characteristics of binding and relaxation
Specific binding of (/sup 125/I)-(-)-cyanopindolol to human tracheal smooth muscle membranes was saturable, stereo-selective and of high affinity (K/sub d/ = 5.3 +/- 0.9 pmol/l and R/sub T/ = 78 +/- 7 fmol/g tissue). The ..beta../sub 1/-selective antagonists atenolol and LK 203-030 inhibited specific (/sup 125/I)-(-)-cyanopindolol binding according to a one binding site model with low affinity in nearly all subjects, pointing to a homogeneous BETA/sub 2/-adrenoceptor population. In one subject using LK 203-030 a small ..beta../sub 1/-adrenoceptor subpopulation could be demonstrated. The beta-mimetics isoprenaline, fenoterol, salbutamol and terbutaline recognized high and low affinity agonist binding sites. Isoprenaline's pK/sub H/- and pK/sub L/-values for the high and low affinity sites were 8.0 +/- 0.2 and 5.9 +/- 0.3 respectively. In functional experiments isoprenaline relaxed tracheal smooth muscle strips having intrinsic tone with a pD/sub 2/-value of 6.63 +/- 0.19. 32 references, 4 figures, 2 tables.
- Research Organization:
- Univ. of Nijmegen, Netherlands
- OSTI ID:
- 6501426
- Journal Information:
- Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 40:26; ISSN LIFSA
- Country of Publication:
- United States
- Language:
- English
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550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AFFINITY
ANIMALS
ASTHMA
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CELL MEMBRANES
DATA
DAYS LIVING RADIOISOTOPES
DISEASES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
EXPERIMENTAL DATA
INFORMATION
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MAN
MEMBRANE PROTEINS
MEMBRANES
MUSCLES
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PATHOGENESIS
PRIMATES
PROTEINS
RADIOISOTOPES
REACTION KINETICS
RECEPTORS
RESPIRATORY SYSTEM
RESPIRATORY SYSTEM DISEASES
SYMPATHOMIMETICS
TRACER TECHNIQUES
TRACHEA
VASODILATION
VASODILATORS
VERTEBRATES