Substance P receptors in rat spleen: characterization and autoradiographic distribution.
The interaction of substance P with intact lymphatic tissue was quantified and autoradiographically visualized, using slide-mounted tissue sections of rat spleen. Radiolabeled substance P binds rapidly to an apparently single class of noninteracting high affinity sites (Kd = 2.4 nmol/L; Bmax = 9.4 fmol/mg protein). The ligand selectivity pattern suggests that substance P binding sites are similar to substance P receptors found in other tissues, including the brain, T lymphocytes, and macrophages. Substance P receptors are highly concentrated in the antigen-trapping spleen marginal zone, with low densities being found in the red pulp. No specific binding of radiolabel to T cell-dependent immunologic domains of the spleen is seen. The distribution of substance P receptors suggests that substance P is probably involved in the control of sensory functions of the immune system.
D000818:Animals; D001345:Autoradiography; D066298:In Vitro Techniques; D007700:Kinetics; D051381:Rats; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013154:Spleen / Q000166:cytology / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*
D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013373:Substance P