Stimulus trafficking

Desensitization of5-HT2C Receptor System and Stimulus Trafficking... 

Watson, C., Chen, G., Irving, P. E., Way, J., Chen, W.-J., and Kenakin, T. P. (2000). The use of stimulus-biased assay systems to detect agonist-specific receptor active states Implications for the trafficking of receptor stimulus by agonists. Mol. Pharmacol. 58 1230-1238. 

Agonist-Directed Trafficking of Receptor Stimulus and Serotonin Receptors... 

Agonist-Directed Trafficking of 5-HT2C Receptor Stimulus... 

Fig. 2. Agonist-directed trafficking of 5-HT2C receptor stimulus. Concentration-response curves for 5-HT2C agonists measuring AA release (PLA2-AA) and IP accumulation (PLC-PI) in CHO-1C19 cells expressing the human 5-HT2c receptor (approx 200 fmol/mg protein). Cells, in serum-free medium, were labeled with 1 pCi/mL [3H]-myo-inositol (10-25 Ci/mmol) for 24 h and with 0.1 pCi/inL [14C]-arachidonic acid (57 mCi/mmol) for 4 h at 37°C. Measurements of PLC-mediated IP accumulation and PLA2-AA release were made from the same multiwell, simultaneously, after 10 min of...

As mentioned earlier, current models of receptor function provide for receptor conformations that interconvert between inactive and active states. The agonist-directed trafficking of receptor stimulus hypothesis suggests that there are multiple active conformations of a receptor that differ in their capacity to couple/activate effector pathways. Such multistate models predict that, like agonist-stimulated responses, constitutive receptor activity and the relative efficacy of inverse agonists should also be response dependent (Fig. 6). 

Berg KA, Maayani S, Goldfarb J, Scaramellini C, Leff P, Clarke WP. Effector pathway-dependent relative efficacy at serotonin type 2A and 2C receptors evidence for agonist-directed trafficking of receptor stimulus. Mol Pharmacol 1998 54 94-104. 

Functionally, CKs are categorized as homeostatic or "inflammatory. Homeostatic CKs are produced and secreted constitutively and are generally involved in lymphocyte trafficking and immune surveillance. Inflammatory CKs are only produced by cells during infection or following a proinflammatory stimulus they prompt the migration of leukocytes to an injured or infected site and can also activate cells to raise an immune response. 

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