Specific substance P binding sites in rat thymus and spleen: in vitro autoradiographic study |
| |
| Authors: | K Shigematsu J M Saavedra M Kurihara |
| |
| Institution: | 1. Hussain Ebrahim Jamal Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan;2. Department of Pharmacology, Faculty of Pharmacy, University of Karachi, Karachi 75270, Pakistan;3. Dr. Panjwani Center for Molecular Medicine and Drug Research, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan;1. Department of Hepatology and Gastroenterology, Qilu Hospital of Shandong University, Jinan, Shandong Province 250012, PR China;2. Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA |
| |
| Abstract: | Substance P binding sites were localized in rat thymus and spleen by incubation of tissue sections with 125I]Bolton-Hunter substance P, 3H]Ultrofilm autoradiography with image analysis coupled to computerized microdensitometry and comparison with 125I standards. The tissue localization of the binding sites was determined with emulsion autoradiography. A single type of specific, saturable, high affinity binding sites was found associated with the vasculature in the medulla of the thymus and the marginal sinus of the spleen, with a Kd of 0.10 and 0.14 nM, respectively. Of all the unlabeled tachykinins tested (substance P, physalaemin, substance K, eledoisin, kassinin, and neuromedin K) substance P was the most potent inhibitor of 125I]Bolton-Hunter substance P binding, with an IC50 of approximately 0.5 nM, indicating the presence of substance P-P binding sites. Our results support the hypothesis of a role for substance P in the modulation of the immune system. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
