Autoradiographic visualization of muscarinic receptor subtypes in human and guinea pig lung

Journal Article · Fri Jun 01 00:00:00 EDT 1990 · American Review of Respiratory Disease (New York); (USA)

DOI:https://doi.org/10.1164/ajrccm/141.6.1559· OSTI ID:6719008

Mak, J C; Barnes, P J ^[1]

---

1. National Heart and Lung Institute, London (England)

Muscarinic receptor subtypes have been localized in human and guinea pig lung sections by an autoradiographic technique, using (3H)(-)quinuclidinyl benzilate (( 3H)QNB) and selective muscarinic antagonists. (3H)QNB was incubated with tissue sections for 90 min at 25 degrees C, and nonspecific binding was determined by incubating adjacent serial sections in the presence of 1 microM atropine. Binding to lung sections had the characterization expected for muscarinic receptors. Autoradiography revealed that muscarinic receptors were widely distributed in human lung, with dense labeling over submucosal glands and airway ganglia, and moderate labeling over nerves in intrapulmonary bronchi and of airway smooth muscle of large and small airways. In addition, alveolar walls were uniformly labeled. In guinea pig lung, labeling of airway smooth muscle was similar, but in contrast to human airways, epithelium was labeled but alveolar walls were not. The muscarinic receptors of human airway smooth muscle from large to small airways were entirely of the M3-subtype, whereas in guinea pig airway smooth muscle, the majority were the M3-subtype with a very small population of the M2-subtype present. In human bronchial submucosal glands, M1- and M3-subtypes appeared to coexist in the proportions of 36 and 64%, respectively. In human alveolar walls the muscarinic receptors were entirely of the M1-subtype, which is absent from the guinea pig lung. No M2-receptors were demonstrated in human lung. The localization of M1-receptors was confirmed by direct labeling with (3H)pirenzepine. With the exception of the alveolar walls in human lung, the localization of muscarinic receptor subtypes on structures in the lung is consistent with known functional studies.

• OSTI ID: 6719008
• Journal Information: American Review of Respiratory Disease (New York); (USA), Journal Name: American Review of Respiratory Disease (New York); (USA) Journal Issue: 6 Vol. 141:6; ISSN ARDSB; ISSN 0003-0805
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
AMINES
ANIMAL TISSUES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
AUTORADIOGRAPHY
AZINES
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BODY
DRUGS
EPITHELIUM
GUINEA PIGS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
KINETICS
LUNGS
MAMMALS
MAN
MEMBRANE PROTEINS
MUSCLES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PARASYMPATHOLYTICS
PARASYMPATHOMIMETICS
PIPERIDINES
PRIMATES
PROTEINS
PYRIDINES
RADIOASSAY
REACTION KINETICS
RECEPTORS
RESPIRATORY SYSTEM
RODENTS
TISSUES
TRITIUM COMPOUNDS
VERTEBRATES