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. 1995 Nov;116(6):2591–2596. doi: 10.1111/j.1476-5381.1995.tb17212.x

Two distinct alpha 1-adrenoceptor subtypes in rabbit liver: a binding study.

T Ohmura 1, I Muramatsu 1
PMCID: PMC1909151  PMID: 8590975

Abstract

1. The characteristics of alpha 1-adrenoceptor subtypes present on rabbit liver membranes were determined by radioligand binding and compared with the characteristics of binding in rat liver. 2. In saturation experiments using rabbit liver, [3H]-prazosin bound to two distinct affinity sites (pKD = 10.3 +/- 0.19 and 8.13 +/- 0.17, Bmax = 11.6 +/- 3.3 and 657.8 +/- 198.0 fmol mg-1 protein, respectively). In studies using rat liver, [3H]-prazosin bound to a single affinity site (pKD = 9.98 +/- 0.27, Bmax = 190.5 +/- 38.5 fmol mg-1 protein). 3. In competition experiments, unlabelled prazosin displaced biphasically the binding of 200 pM [3H]-prazosin to the rabbit liver; the resulting two pK1 values (9.85 +/- 0.08 and 8.01 +/- 0.09) were consistent with the affinity constants obtained in the saturation experiments. Two sites were also recognized by doxazosin (pKI 9.73 +/- 0.78 and 8.12 +/- 0.34), 2-(2,6-dimethoxy phenoxyethyl)-aminomethyl-1,4-benzo-dioxane (WB4101) pKI (9.74 +/- 0.32 and 7.57 +/- 0.34) and 5-methylurapidil (pKI 8.69 +/- 0.27 and 6.75 +/- 0.35), and the population of low affinity sites for the three antagonists was approximately 70%. Two distinct affinity constants (pKI 8.55 +/- 0.09 and 7.90 +/- 0.09) were also calculated for alpha-ethyl-3,4,5-trimethoxy-alpha-(3-((2-(2-methoxyphenoxy) ethyl)-amino)-propyl)-benzeneacetonitrile fumarate (HV723). 4. By contrast, [3H]-prazosin binding sites of rat liver membranes were detected as a single population with a high affinity for prazosin (pKI 10.01 +/- 0.08), and doxazosin (pKI 9.67 +/- 0.20) but with a low affinity for WB4101 (pKI 8.25 +/- 0.09), 5-methylurapidil (pKI 7.22 +/- 0.01) and HV723 (pKI 8.88 +/- 0.05). 5. These results indicate the presence of two distinct alpha 1-adrenoceptor subtypes in the rabbit liver, but only a single site in rat liver. The pharmacological characteristics of prazosin-high and -low sites in rabbit liver suggest identity with alpha 1A and putative alpha 1L subtypes, respectively. The site in rat liver is of the alpha 1B subtype.

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Selected References

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  1. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
  2. Cheng Y., Prusoff W. H. Relationship between the inhibition constant (K1) and the concentration of inhibitor which causes 50 per cent inhibition (I50) of an enzymatic reaction. Biochem Pharmacol. 1973 Dec 1;22(23):3099–3108. doi: 10.1016/0006-2952(73)90196-2. [DOI] [PubMed] [Google Scholar]
  3. Cotecchia S., Schwinn D. A., Randall R. R., Lefkowitz R. J., Caron M. G., Kobilka B. K. Molecular cloning and expression of the cDNA for the hamster alpha 1-adrenergic receptor. Proc Natl Acad Sci U S A. 1988 Oct;85(19):7159–7163. doi: 10.1073/pnas.85.19.7159. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. De Lean A., Hancock A. A., Lefkowitz R. J. Validation and statistical analysis of a computer modeling method for quantitative analysis of radioligand binding data for mixtures of pharmacological receptor subtypes. Mol Pharmacol. 1982 Jan;21(1):5–16. [PubMed] [Google Scholar]
  5. Drew G. M. What do antagonists tell us about alpha-adrenoceptors? Clin Sci (Lond) 1985;68 (Suppl 10):15s–19s. doi: 10.1042/cs068s015. [DOI] [PubMed] [Google Scholar]
  6. García-Sáinz J. A., Romero-Avila M. T., Alcántara Hernández R., Macias-Silva M., Olivares-Reyes A., González-Espinosa C. Species heterogeneity of hepatic alpha 1-adrenoceptors: alpha 1A-, alpha 1B- and alpha 1C-subtypes. Biochem Biophys Res Commun. 1992 Jul 31;186(2):760–767. doi: 10.1016/0006-291x(92)90811-x. [DOI] [PubMed] [Google Scholar]
  7. Gross G., Hanft G., Rugevics C. 5-Methyl-urapidil discriminates between subtypes of the alpha 1-adrenoceptor. Eur J Pharmacol. 1988 Jul 7;151(2):333–335. doi: 10.1016/0014-2999(88)90819-9. [DOI] [PubMed] [Google Scholar]
  8. Han C., Abel P. W., Minneman K. P. Heterogeneity of alpha 1-adrenergic receptors revealed by chlorethylclonidine. Mol Pharmacol. 1987 Oct;32(4):505–510. [PubMed] [Google Scholar]
  9. Hanft G., Gross G. Subclassification of alpha 1-adrenoceptor recognition sites by urapidil derivatives and other selective antagonists. Br J Pharmacol. 1989 Jul;97(3):691–700. doi: 10.1111/j.1476-5381.1989.tb12005.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hiramatsu Y., Muraoka R., Kigoshi S., Muramatsu I. Identification of alpha 1-adrenoceptor subtypes in rat lung by binding of [3H]-prazosin and [3H]-WB4101. J Recept Res. 1994 Feb;14(2):75–98. doi: 10.3109/10799899409066998. [DOI] [PubMed] [Google Scholar]
  11. Järhult J., Andersson P. O., Holst J., Moghimzadeh E., Nobin A. On the sympathetic innervation to the cat's liver and its role for hepatic glucose release. Acta Physiol Scand. 1980 Sep;110(1):5–11. doi: 10.1111/j.1748-1716.1980.tb06623.x. [DOI] [PubMed] [Google Scholar]
  12. Järhult J., Falck B., Ingemansson S., Nobin A. The functional importance of sympathetic nerves to the liver and endocrine pancreas. Ann Surg. 1979 Jan;189(1):96–100. doi: 10.1097/00000658-197901000-00018. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Laz T. M., Forray C., Smith K. E., Bard J. A., Vaysse P. J., Branchek T. A., Weinshank R. L. The rat homologue of the bovine alpha 1c-adrenergic receptor shows the pharmacological properties of the classical alpha 1A subtype. Mol Pharmacol. 1994 Sep;46(3):414–422. [PubMed] [Google Scholar]
  14. Lomasney J. W., Cotecchia S., Lefkowitz R. J., Caron M. G. Molecular biology of alpha-adrenergic receptors: implications for receptor classification and for structure-function relationships. Biochim Biophys Acta. 1991 Oct 26;1095(2):127–139. doi: 10.1016/0167-4889(91)90075-9. [DOI] [PubMed] [Google Scholar]
  15. McPherson G. A. Analysis of radioligand binding experiments. A collection of computer programs for the IBM PC. J Pharmacol Methods. 1985 Nov;14(3):213–228. doi: 10.1016/0160-5402(85)90034-8. [DOI] [PubMed] [Google Scholar]
  16. Morrow A. L., Creese I. Characterization of alpha 1-adrenergic receptor subtypes in rat brain: a reevaluation of [3H]WB4104 and [3H]prazosin binding. Mol Pharmacol. 1986 Apr;29(4):321–330. [PubMed] [Google Scholar]
  17. Munson P. J., Rodbard D. Ligand: a versatile computerized approach for characterization of ligand-binding systems. Anal Biochem. 1980 Sep 1;107(1):220–239. doi: 10.1016/0003-2697(80)90515-1. [DOI] [PubMed] [Google Scholar]
  18. Muramatsu I., Kigoshi S., Oshita M. Two distinct alpha 1-adrenoceptor subtypes involved in noradrenaline contraction of the rabbit thoracic aorta. Br J Pharmacol. 1990 Nov;101(3):662–666. doi: 10.1111/j.1476-5381.1990.tb14137.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Muramatsu I., Oshita M., Ohmura T., Kigoshi S., Akino H., Gobara M., Okada K. Pharmacological characterization of alpha 1-adrenoceptor subtypes in the human prostate: functional and binding studies. Br J Urol. 1994 Nov;74(5):572–578. doi: 10.1111/j.1464-410x.1994.tb09186.x. [DOI] [PubMed] [Google Scholar]
  20. Noguchi H., Muraoka R., Kigoshi S., Muramatsu I. Pharmacological characterization of alpha 1-adrenoceptor subtypes in rat heart: a binding study. Br J Pharmacol. 1995 Mar;114(5):1026–1030. doi: 10.1111/j.1476-5381.1995.tb13308.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Oshita M., Kigoshi S., Muramatsu I. Pharmacological characterization of two distinct alpha 1-adrenoceptor subtypes in rabbit thoracic aorta. Br J Pharmacol. 1993 Apr;108(4):1071–1076. doi: 10.1111/j.1476-5381.1993.tb13507.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Oshita M., Kigoshi S., Muramatsu I. Three distinct binding sites for [3H]-prazosin in the rat cerebral cortex. Br J Pharmacol. 1991 Dec;104(4):961–965. doi: 10.1111/j.1476-5381.1991.tb12533.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Perez D. M., Piascik M. T., Graham R. M. Solution-phase library screening for the identification of rare clones: isolation of an alpha 1D-adrenergic receptor cDNA. Mol Pharmacol. 1991 Dec;40(6):876–883. [PubMed] [Google Scholar]
  24. Perez D. M., Piascik M. T., Malik N., Gaivin R., Graham R. M. Cloning, expression, and tissue distribution of the rat homolog of the bovine alpha 1C-adrenergic receptor provide evidence for its classification as the alpha 1A subtype. Mol Pharmacol. 1994 Nov;46(5):823–831. [PubMed] [Google Scholar]
  25. Schwinn D. A., Lomasney J. W., Lorenz W., Szklut P. J., Fremeau R. T., Jr, Yang-Feng T. L., Caron M. G., Lefkowitz R. J., Cotecchia S. Molecular cloning and expression of the cDNA for a novel alpha 1-adrenergic receptor subtype. J Biol Chem. 1990 May 15;265(14):8183–8189. [PubMed] [Google Scholar]
  26. Schwinn D. A., Lomasney J. W. Pharmacologic characterization of cloned alpha 1-adrenoceptor subtypes: selective antagonists suggest the existence of a fourth subtype. Eur J Pharmacol. 1992 Dec 1;227(4):433–436. doi: 10.1016/0922-4106(92)90162-o. [DOI] [PubMed] [Google Scholar]
  27. Torres-Márquez M. E., Villalobos-Molina R., García-Sáinz J. A. Alpha 1-adrenoceptor subtypes in aorta (alpha 1A) and liver (alpha 1B). Eur J Pharmacol. 1991 Mar 25;206(3):199–202. doi: 10.1016/s0922-4106(05)80019-7. [DOI] [PubMed] [Google Scholar]

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