Coupling with adenylate cyclase

Figure 4. Representation of the classification of the dopamine receptor based on its coupling with adenylate cyclase activity. DA+ receptors (left) are coupled to adenylate cyclase through the Ns GTP-binding protein (91) with secondary activation of adenylate cyclase. DA. receptors (middle) are coupled through the Ni GTP-binding protein, thus resulting in inhibition of cyclic AMP formation. DA0 receptors (right) are those uncoupled to cyclic AMP formation, the example being possibly some autoreceptors on nigrostriatal dopaminergic neurons.

Bouhelal R, Smounya L, Bockaert J. 5-HTm receptors are negatively coupled with adenylate cyclase in rat substantia nigra. Eur J Pharmacol 1988 151 189-196. 

Dumuis A, Bouhelal R, Sebben M, Cory R, Bockaert J. A nonclassical 5-hydroxytryptamine receptor positively coupled with adenylate cyclase in the central nervous system. Mol Pharmacol 1988 34 880-887. 

Enjalbert A, Bockaert J (1983) Pharmacological characterization of the D2 dopamine receptor negatively coupled with adenylate cyclase in rat anterior pituitary. Mol Pharmacol 23 576-584. 

Wojcik, W. J. and Neff, N. H. (1984) Gamma-aminobutyric acid B receptors are negatively coupled to adenylate cyclase in brain and in the cerebellum these receptors may be associated with granule cells. Mol. Pharmacol. 25, 24-28. 

Yocca ED, Iben L, Meller E Lack of apparent receptor reserve at postsynaptic 5-hydroxytryptamine lA receptors negatively coupled to adenyl cyclase activity in rat hippocampal membranes. Mol Pharmacol 41 1066-1072, 1992 Yoney TH, Pigott TA, L Heureux F, et al. Seasonal variation in obsessive-compulsive disorder preliminary experience with light treatment. Am J Psychiatry 148 1727-1729, 1991... 

Orly, J., and Schramm, M. (1976). Coupling of catecholamine receptor from one cell with adenylate-cyclase from another cell by cell-fusion. Proc. Natl. Acad. Sci. USA 73, 4410-4414. 

There are three important ADP receptors on the platelet surface (16). The P2X, inotrophic receptor is responsible for rapid influx of calcium into the cytosol. The P2Y, receptor mediates mobilization of calcium through activation of PLC and shape change. The P2Y,2 receptor is coupled to adenyl cyclase inhibition mediated by a G-protein with subsequent decrease in the cAMP The decrease in cAMP stimulates dephosphorylation of VASP that is closely correlated with the GPIIb/llla activation. 

It is very likely an inaccuracy to call the D-l dopamine receptor an enzyme. Because of the effects of guanine nucleotides on dopamine-stimulated adenylate cyclase, it is likely by analogy with other receptors (i.e. the 3 receptor) that the D-l receptor is a distinct molecular entity which is coupled to adenylate cyclase by a guanine nucleotide binding subunit. Proof of this point, of course, will require physical separation of these entities. 

Coupling of dopamine receptors with adenylate cyclase DAj., DA and DAq receptors... 

TP Receptors. TP receptors are generally regarded as signaling through Gq to cause an increase in the concentration of intracellular calcium (183). However, there are reports that TP receptors may also couple to G,i, G.., and Gi3 (184-186). Furthermore, there have also been reports that TP receptor splice variants, while both couplingto Gq, may interact differently with adenylate cyclase. Thus, the TPa receptor isoform induces increases in intracellular cAMP, whereas the TPj3 isoform induces decreases in intracellular cAMP levels (187). 

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