Autoradiographic localization of substance P binding sites in guinea-pig airways.
The distribution of substance P (SP) binding sites in guinea-pig airway was examined by in vitro autoradiography with tritium- and iodine-labeled SP. Specific SP binding sites were most abundant in tracheobronchial smooth muscle but were also detected in the mucosa/submucosa. Binding within the mucosa/submucosa was especially high in the region of glands. Binding of iodine-labeled SP to cartilage was negligible. Tritium-labeled SP bound non-specifically to airway cartilage. These observations are consistent with the proposed effects of SP-containing afferent nerves on airway resistance and vascular permeability. The localization of specific SP binding sites suggests that SP may also affect exocrine glands in the respiratory tract.
D000818:Animals; D001345:Autoradiography; D001980:Bronchi / Q000378:metabolism*; D006168:Guinea Pigs; D008297:Male; D009092:Mucous Membrane / Q000378:metabolism; D009130:Muscle, Smooth / Q000032:analysis; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000032:analysis*; D014132:Trachea / Q000378:metabolism*
D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter