In vitro labeled receptors were incubated with various synthetic or natural agonists or antagonists and submitted to trypsin digestion .
in vitro labeled receptors were incubated with various synthetic or natural agonists or antagonists and submitted to trypsin digestion .
B-protein_family_or_group I-protein_family_or_group I-protein_family_or_group I-protein_family_or_group O O O O O O O O O B-other_organic_compound O O O B-protein_molecule O O