Silent receptor

Agonists that yield parallel dose-response curves with the same maximum are assumed to act on the same site but with different affinities. Nonreceptor binding to a site of loss (sometimes called a silent receptor) can thus be distinguished from relevant binding. 

The occasional high enantioselectivity of the second major drug binding site of serum albumin (the indole-benzodiazepine site, site II) has led Muller (4) to describe HSA as a "silent receptor." Compounds thought to bind to site II include tryptophan, diazepam, and octanoate (59). The enantioselective binding of tryptophan to albumin is thought to arise from differential attachment of the isomers to this site (60). 

W. E. Muller and U. Wollert, Human serum albumin as a silent receptor for drugs and endogenous substances, Pharmacol., 19 56 (1979). 

A. Muller, L. Toma, H. Bogge et al.. Synergetic Activation of Silent Receptor Sites Leading to a New Type of Inclusion Complex Integration of a 64-Membered Ring Comprising K" and S04 Ions into a Molybdenum Oxide-Based Nanoobject, Chem. Commun. 2003, 2000-2001. 

Maack T, Suzuki M, Almeida FA, Nussenzveig D, Scarborough RM, McEnroe GA et al. Physiological role of silent receptors of atrial natriuretic factor. Science 1989 238 675-678. 

GPR4, OGR1, and TDAG8 are GPCRs regulated by extracellular pH in the physiological range. These receptors are silent at pH 7.8, and folly activated at pH 6.8. 

Although histamine has mixed excitatory and inhibitory effects on central neurons, those antihistamines (Hi-receptor antagonists) that enter the brain produce sedation this indicates that the predominant overall effect of histamine is excitatory. The preferred explanation for this rests on evidence that histaminergic neurons in the posterior hypothalamus are active in waking and silent in deep SWS and REM sleep. 

Locati M, Torre YM, Galliera E, et al. Silent chemoattractant receptors D6 as a decoy and scavenger receptor for inflammatory CC chemokines. Cytokine Growth Factor Rev 2005 16 679-686. 

Liu L, Graham G, Hu T, et al. The silent chemokine receptor D6 is required for generating T cell responses that mediate experimental autoimmune encephalomyelitis. J Immunol 2006 177(1) 17-21. 

Fletcher, A., Forster, E. A., Bill, D. J. et al. (1996). Electrophysiological, biochemical, neurohormonal and behavioral studies with WAY-100635, a potent, selective and silent 5-HTia receptor antagonist. Behav. Brain Res. 73, 337-53. 

NMDA and AMPA receptors are spread across the post-synaptic density (PSD), whereas metabotropic glutamate receptors (except mGluR7) are located along the periphery of the PSD (Fig. 15-2). NMDA receptors appear to be present at most or all glutamatergic synapses whereas the content of AMPA receptors is variable - from zero to about 50 receptors per PSD [33]. Some synapses are silent , meaning that activation of them does not elicit AMPA receptor currents when the plasma membrane is hyperpolarized and Mg2+ blocks NMDA receptors. Such silent synapses contain only NMDA receptors. However, AMPA receptors are recruited from the cytosol to the PSD to activate such silent synapses in LTP. 

Lerma J, Morales M, Vicente MA, Herreras O (1997) Glutamate receptors of the kainate type and synaptic transmission. Trends Neurosci 20 9-12 Liao DZ, Hessler NA, Malinow R (1995) Activation of postsynaptically silent synapses during pairing-induced LTP in CAl region of hippocampal slice. Nature 375 400-404... 

Contraindications Basilar or hemiplegic migraine, coronary artery disease, ischemic heart disease (including angina pectoris, history of Ml, silent ischemia, and Prinzmetal s angina), uncontrolled hypertension, use within 24 hours of ergotamine-contain-ing preparations or another serotonin receptor agonist, use within 14 days of MAOls... 

Cantello R, Gianell M, Civardi C, et al Magnetic brain stimulation the silent period after the motor evoked potential. Neurology 42 1951-1959, 1992 Canton T, Doble A Evidence for different binding domains on the GABAa benzodiazepine receptor for benzodiazepines and cyclopyrrolones. Clin Neuro-pharmacol 15 [suppl 1 pt B) 125, 1992... 

Cu(II) is one of the best examples of a redox active guest, but apparently not when it is imprisoned in a cryptand such as 53. In this case, the Cu(II) is silent over a wide potential range during cyclic voltammetry. System 53 is designed as a lumophore-spacer-receptor system such as 28-30 and 33-34 in Section 1 with multiple lumophores. It also shows similar luminescence off-on switching with and even with Cu(II). The possibility of Cu(II) induced production of from moisture appears to have been ruled out. The absence of EET is a mystery which can only be dispelled by further studies on this interesting system. 

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