Receptor receptor

Receptor Receptor Probe Modulator Effect1 Difference2... 

Serotoninergic System. Figure 1 Graphical representation of the current classification of 5-hydroxytryptamine (5-HT) receptors. Receptor subtypes represented by shaded boxes and lowercase designate receptors that have not been demonstrated to definitively function in native systems. Abbreviations 3-5r cyclic adenosine monophosphate (cAMP) phospholipase C (PLC) negative (-ve) positive (+ve)... 

Figure 42-1. Specificity and seiectivity of hormone receptors. Many different moiecuies circuiate in the extraceiiuiarfiuid (ECF), but oniy a few are recognized by hormone receptors. Receptors must seiect these moiecuies from among high concentrations of the other moiecuies. This simpiified drawing shows that a ceii may have no hormone receptors (1), have one receptor (2+5-F6), have receptors for severai hormones (3), or have a receptor but no hormone in the vicinity (4).

GABA receptors. Receptors for y-aminobutyric acid. GABA is an amino acid that acts as an inhibitory neurotransmitter in the CNS. 

Ferre, S, Fredholm, BB, Morelli, M, Popoli, P and Fuxe, K (1997) Adenosine-dopamine receptor-receptor interaction as an integrative mechanism in the basal ganglia. Trends Neurosci. 20 482-487. 

G-Protein-Coupled/Integrin Receptors Receptor/Nonreceptor Kinases/Phosphatases Transcription Factors/Proteases... 

Here, the agonist-receptor complex (AR) combines with a G-protein (G) to form a ternary complex (ARG ), which can initiate further cellular events, such as the activation of adenylate cyclase. However, this simple scheme (the ternary complex model) was not in keeping with what was already known about the importance of isomerization in receptor activation (see Sections 1.2.3 and 1.4.3), and it also failed to account for findings that were soon to come from studies of mutated receptors. In all current models of G-protein-coupled receptors, receptor activation by isomerization is assumed to occur so that the model becomes ... 

The crystal structures of monomeric ligands such as GH and EPO in complex with their respective receptors show that these hormones are bivalent and one ligand binds simultaneously to two receptor molecules to form a 1 2 (ligand receptor) complex. Receptor dimerization is further stabilized by additional receptor-receptor interactions. 

The binding of a hormone to its receptor initiates intracellular events that direct the hormone s action. Ultimately, all hormones produce their effects by altering intracellular protein activity. However, the mechanism by which this occurs depends on the location of the hormone receptor. Receptors are typically located on the cell surface or in the cell nucleus. As a result, most hormones carry out their effects by means of two general mechanisms ... 

Table 11.4 shows that clozapine has approximately 10 times higher affinity for the D4 and 5-HT2A-receptors than the D2-receptor and shows a greater occupancy of the 5-HT2 than the D2-like receptors. The other atypical neuroleptic risperidone has a similar affinity for the two D2-like receptors but an affinity for the 5-HT2a-receptor that is just over 3 times lower than for the D2-receptor. Receptor occupancy in vivo shows a similar profile to clozapine. In contrast, haloperidol s affinity for the D4-receptor is just under 3 times lower and over 100 times lower for the 5-HT2a-receptor, with no binding to the latter in vivo. The fractional occupancy of striatal... 

Cholinergic receptors Receptors for acetylcholine are classified into muscarinic (muscarine is a selective agonist) and nicotinic (nicotine is a selective agonist). There are five muscarinic (mj to m5) and two nicotinic (neuronal, or ganglionic, and skeletal muscular) subtypes. 

The different subtypes of levamisole receptor (receptor heterogeneity) were illustrated by the presence, in some patches, of channels with different conductances (Fig. 21.9). The different conductances were seen as channel currents opening to different levels producing different peaks in the scatter... 

TABLE 17-3 Antagonists for Pjx receptors Receptor Antagonist (rat plC50, m)... 

Shupnik MA (2002) Oestrogen receptor, receptor variants and oestrogen actions in the hypothalamic-pituitary axis. J Neuroendocrinol 14 85-94... 

Agnati, L.F., Ferre, S., Lluis, C., Franco, R. and Fuxe, K. (2003) Molecular mechanisms and therapeutical implications of intramembrane receptor/receptor interactions among heptahelical receptors with examples from the striatopallidal GABA neurons. Pharmacological Reviews, 55, 509-550. 

Reaper, C.M., Fanelli, F., Buckingham, S. D Millar, N.S. and Sattelle, D.B. (1998) Antagonist profile and molecular dynamic simulation of a Drosophila melanogaster muscarinic acetylcholine receptor. Receptors Channels, 5,... 

Caveolae, Folate Receptor, Receptor Clustering, and Potocytosis... 

Some sensory neurons of the VNO express two gene superfamilies, termed Vlr and V2r, that encode over 240 proteins of the seven-transmembrane type (Matsunami and Buck, 1997). These G-protein-linked putative pheromone receptors are distantly related to the main olfactory system s receptors. Receptors of the VNO are linked to different G-proteins, and their extracellular N-terminal domains are longer than those of the receptors in the main olfactory system. (Vi receptors are linked to Gi-proteins and V2 receptors to Go-proteins). The intracellular excitation mechanism in VNO sensory neurons also differs from that in the main olfactory systems instead of linking to adenylyl cyclase, the VNO receptors activate the phosphoinositol second messenger system. This has been demonstrated in several mammalian species. In hamsters, aphrodisin increases inositol 1,4,5-trisphosphate (IP3) levels in VNO membranes. Boar seminal fluid and urine stimulate increases of IP3 in the VNO of the female pig. (However, in the pig, the VNO is not necessarily essential for responses to pheromones [Dorries etal., 1997]). 

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