In vivo autoradiographic demonstration of. beta. -adrenergic binding sites in adult rat type II alveolar epithelial cells

Journal Article · Mon Feb 06 04:00:00 EST 1984 · Life Sci.; (United States)

DOI:https://doi.org/10.1016/0024-3205(84)90484-3· OSTI ID:6241679

Smith, D M; Sidhu, M K

Adult male rats were injected intravenously with the muscarinic binding probe /sup 3/H-Quinuclidinyl benzilate (QNB) or the ..beta..-adrenergic probe /sup 3/H-dihydroalprenolol (DHA). Other rats were pre-treated with an intraperitoneal injection of a 500-fold excess of L-isoproterenol prior to the DHA. Light microscopic autoradiography of 0.5 ..mu..m sections of lung from the QNB group demonstrated very little labelling even after 6 months of exposure. In constrast, trachealis smooth muscle from these animals contained substantial labelling. Autoradiographs of lung from rats injected with DHA demonstrated labelling which was well localized over alveolar septa and concentrated over the cytoplasm of type II cells. Quantitative analysis of labelling in the DHA groups indicated a significant reduction of labelling in animals treated with L-isoproterenol prior to DHA, in both the alveolar parenchyma in general and over type II cells. The results of this study provide morphologic evidence for the uptake and specific binding of ..beta..-adrenergic antagonists by the adult lung in vivo, while failing to demonstrate similar binding of a muscarinic probe. In addition, the results demonstrate specific ..beta..-adrenergic receptors on type II cells in vivo and substantiate the view of a direct effect of ..beta..-adrenergic agonists on alveolar type II cells.

• Research Organization: Wellesley Coll., MA
• OSTI ID: 6241679
• Journal Information: Life Sci.; (United States), Journal Name: Life Sci.; (United States) Vol. 34:6; ISSN LIFSA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMAL TISSUES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
BIOLOGICAL LOCALIZATION
BODY
CHEMICAL BONDS
DRUGS
EPITHELIUM
IN VIVO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LUNGS
MAMMALS
MUSCLES
ORGANS
RADIOASSAY
RATS
RECEPTORS
RESPIRATORY SYSTEM
RODENTS
SYMPATHOMIMETICS
TISSUES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES