Adrenoceptor cloning

So far three subtypes of ft receptors have been identified and cloned. They differ in their distribution, the Pi type being found in the heart, the P2 in lung, smooth muscle, skeletal muscle and liver, while the P type occurs in adipose tissue. There is evidence that P2 adrenoceptors occur on the lymphocyte membrane also but the precise function there is unknown. 

Primary structure of the human kidney aj-adrenoceptor. The amino acid sequence Is represented by the one-letter code. (Reprinted with permission from Regan JW et al. Cloning and expression of a human kidney cDNA. Proc Natl Acad Scl USA 85 6301, 1988.)... 

Molecular genetic techniques have confirmed the existence of multiple subtypes of p-adrenoceptors. Pi-Receptors and Pj-receptors have been cloned, and recent molecular biological evidence indicates the existence of at least one additional p-receptor sub-type, called the p3-receptor. It is suggested that the P3-receptor may mediate some of the metabolic effects of catecholamines, although no available p-blocker has been shown to rely on Pa-receptor antagonism for its therapeutic effectiveness. 

Two main subtypes of P adrenoreceptors, P and P2, have been identified in the periphery and in the CNS (Minneman et ak, 1979 Palacios and Kuhar, 1980). Both are located at postsynaptic terminals and have been cloned. In the periphery, P receptors are located in myocardial tissue, and P2 receptors are located in pulmonary bronchi and bronchioli, as well as in some blood vessels. P Adrenoceptors are the major subtype throughout the brain, except for the cerebellum, where P2 receptors are predominant. Areas that contain high concentrations of P adrenoceptors include the superfi-... 

Receptor binding (example -adrenoceptors) Cell membrane fractions from organs or cultured cells cloned receptors In vitro Receptor affinity and selectivity... 

I. -S., Lesnick, J.D., Ford, A.P.D.W., Daniels, D.V., Eglen, R.M., Clarke, D.E., Bach, C., Chan, FEW. Molecular cloning, genomic characterization and expression of novel human aiA-adrenoceptor isoforms. FEBS Lett. 1998, 422, 279-283 ... 

Abstract Presynaptic metabotropic receptors for acetylcholine and adrenaline/ noradrenaline were first described more than three decades ago. Molecular cloning has resulted in the identification of five G protein-coupled muscarinic receptors (Mi — M5) which mediate the biological effects of acetylcholine. Nine adrenoceptors (ociabd,oc2abc,Pi23) adrenafine/noradrenaline signals between cells. 

Adrenoceptors (AR) are G protein-coupled receptors which mediate the biological effects of the endogenous catecholamines, adrenaline and noradrenaline. Nine adrenoceptor subtypes have been cloned which can be grouped into three different... 

Molecular cloning has led to the identification of a great complexity of receptor subtypes in the cholinergic and adrenergic systems. Five muscarinic GPCRs and altogether nine adrenoceptors mediate the biological effects of acetylcholine and... 

T10. Tseng-Crank, J., Kost, T., Goetz, A., Hazum, S., Roberson, K. M., et al., The alpha 1C-adrenoceptor in human prostate cloning, functional expression, and localization to specific prostatic cell types. Br. J. Pharmacol. 115, 1475-1485 (1995). 

Daniels DV, Gever JR, Jasper JR, et al. Human cloned a1A-adrenoceptor isoforms display a1L-adrenoceptor pharmacology in functional studies. Eur J Pharmacol 1999 370 337-343. 

Horie K, Obika K, Foglar R, Tsujimoto G. Selectivity of the imidazoline a-adrenoceptor agonists (oxymetazoline and cirazoline) for human cloned a,-adrenoceptor subtypes. Br J Pharmacol 1995 116 1611-1618. 

Richardson J, Chatwin H, Hirasawa A, Tsujimoto G, Evans PD. Agonist-specific coupling of a cloned human a, A-adrenoceptor to different second messenger pathways. Naunyn-Schmiedebergs Arch Pharmacol 2003 367 333-341. 

Airriess CN, Rudling JE, Midgley JM, Evans PD. Selective inhibition of adenylyl cyclase by octopamine via a human cloned a2A-adrenoceptor. Br J Pharmacol 1997 122 191-198. 

Rudling JE, Richardson J, Evans PD. A comparison of agonist-specific coupling of cloned human a2-adrenoceptor subtypes. Br J Pharmacol 2000 131 933-941. 

Venkatachalam K, Montell C (2007) TRP channels. Annu Rev Biochem 76 387—417 Wilson RP (1994) Utilization of dietary carbohydrate by fish. Aquaculture 124 67-80 Yasuoka A, Abe K, Arai S, Emori Y (1996) Molecular cloning and functional expression of the alphalA-adrenoceptor of medaka fish, Oryzias latipes. Eur J Biochem 235 501-507 Yasuoka A, Aihara Y, Matsumoto I, Abe K (2004a) Phospholipase C-beta 2 as a mammalian taste signaling marker is expressed in the multiple gustatory tissues of medaka fish, Oryzias latipes. Mech Dev 121 985-989... 

Figure 4. Correktion between the binding afSnity (pKi) for the cloned a, -AR and the functional afSnity (pKb) for the aj-adrenoceptors in human prostate (A) and rabbit urethra (B). Dashed line represents the line of identity.

Based on functional assays using cells transfected with the recombinant adrenoceptor, and on the effect of receptor environment on antagonist affinity, it has been proposed that the a,L adrenoceptor represents an affinity state of the adrenoceptor (Williams et al., 1996 Ford et al., 1997). This may explain why efforts to clone a discrete protein having characteristics have been unsuccessful. 

D.P., Rockell, C.M., Young, P.W., 1995. Synthesis of a selective alpha-2A adrenoceptor antagonist, BRL 48962, and its characterization at cloned human alpha-adrenoceptors. Bioorg. Med. Chem. 3, 1693-1698. 

With the rapid development of additional pharmacological tools which displayed improved selectivity for either ai, az- or / -adrenoceptors in functional and radioligand binding studies, and the advent of molecular biological techniques by cloning of distinct adrenoceptor subtypes being in accord with their native correlates, the existence of additional subtypes became apparent. At present, the family of adrenoceptors comprises three ai-adrenoceptor subtypes (ttiA, ttiB, ctio), four a2-adrenoceptor subtypes (a2A, 2b, 2c, 2d), and three adrenoceptor subtypes ( 1, 2, 3). 

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