title: Generation and characterization of a human bradykinin receptor B1 transgenic rat as a pharmacodynamic model.
abstract: Antagonists of the B1 bradykinin receptor (B1R) offer the promise of novel therapeutic agents for the treatment of inflammatory and neuropathic pain. However, the in vivo characterization of the pharmacodynamics of B1R antagonists is hindered by the low level of B1R expression in healthy tissue and the profound species selectivity exhibited by many compounds for the human B1R. To circumvent these issues, we generated a transgenic rat expressing the human B1R under the control of the neuron-specific enolase promoter. Membranes prepared from whole brain homogenates of heterozygous transgenic rats indicate a B1R expression level of 30 to 40 fmol/mg; there is no detectable B1R expression in control nontransgenic rats. The pharmacological profile of the B1R expressed in the transgenic rat matches that expected of the human, but not the rat receptor. The mapping of the transgene insertion site to rat chromosome 1 permitted the development of a reliable assay for the identification of homozygous transgenic rats. Significantly, homozygous transgenic rats express 2-fold more B1R than heterozygous animals. Autoradiographic analyses of tissue sections from transgenic rats reveal that the B1R is broadly expressed in both the brain and spinal cord. The human B1R expressed in the transgenic rat functions in an in vitro contractile assay and thus has the potential to elicit a functional response in vivo. Using the humanized B1R transgenic rat, an assay was developed that is suitable for the routine evaluation of a test compound's ability to occupy the human B1R in the central nervous system.
authors.affiliation: Department of Molecular Neurology, Merck Research Lab, WP26A-3000, P.O. Box 4, West Point, PA 19486, USA. fred_hess@merck.com
authors.forename: J Fred
authors.initials: JF
authors.lastname: Hess
authors.forename: Richard W
authors.initials: RW
authors.lastname: Ransom
authors.forename: Zhizhen
authors.initials: Z
authors.lastname: Zeng
authors.forename: Raymond S L
authors.initials: RS
authors.lastname: Chang
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Hey
authors.forename: Lee
authors.initials: L
authors.lastname: Warren
authors.forename: Charles M
authors.initials: CM
authors.lastname: Harrell
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Murphy
authors.forename: Tsing-Bau
authors.initials: TB
authors.lastname: Chen
authors.forename: Patricia J
authors.initials: PJ
authors.lastname: Miller
authors.forename: Edward
authors.initials: E
authors.lastname: Lis
authors.forename: Duane
authors.initials: D
authors.lastname: Reiss
authors.forename: Raymond E
authors.initials: RE
authors.lastname: Gibson
authors.forename: M Kristine
authors.initials: MK
authors.lastname: Markowitz
authors.forename: Robert M
authors.initials: RM
authors.lastname: DiPardo
authors.forename: Dai-Shi
authors.initials: DS
authors.lastname: Su
authors.forename: Mark G
authors.initials: MG
authors.lastname: Bock
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gould
authors.forename: Douglas J
authors.initials: DJ
authors.lastname: Pettibone
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics* / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D016466:CHO Cells; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D010446:Peptide Fragments / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D051381:Rats / Q000235:genetics*; D043783:Receptor, Bradykinin B1 / Q000096:biosynthesis* / Q000235:genetics*
chemical_list: D010446:Peptide Fragments; D043783:Receptor, Bradykinin B1