Cloning and pharmacological characterization of human alpha-1 adrenergic receptors: sequence corrections and direct comparison with other species homologues.
We have cloned cDNAs encoding three human alpha-1 adrenergic receptor (AR) subtypes and characterized pharmacological properties of the expressed receptor protein. A number of significant sequence corrections have been identified and compared with previously published data, at both nucleotide and amino acid levels; the most major differences occur for the human alpha-1a/dAR. Pharmacological characterization was performed simultaneously using six cloned alpha-1AR subtypes (human and rat alpha-1a/d, human and hamster alpha-1b, human and bovine alpha-1c) stably expressed in rat-1 fibroblasts at approximately equal receptor concentrations (1-2 pmol/mg of total protein). In general, human alpha-1AR subtypes have similar pharmacology compared to their rat, hamster and bovine homologs, although a few minor species differences important for alpha-1AR classification are noted. In addition, much lower inactivation (approximately 20%) by the alkylating agent chloroethylclonidine is noted in this study compared to previous reports for both human and bovine alpha-1cAR membrane preparations. All six alpha-1AR subtypes couple to phosphoinositide hydrolysis in a pertussis toxin-insensitive manner, including the cloned human alpha-1a/dAR which had not been expressed previously. In spite of significant sequence differences between human alpha-1ARs and their other species counterparts, previously established ligand selectivity remains fairly comparable. In summary, these data represent the first side-by-side comparison of pharmacological properties between species homologs of alpha-1AR subtypes and should facilitate the development of alpha-1AR subtype selective drugs for clinical use.
Schwinn
D A
DA
Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina.
Johnston
G I
GI
Page
S O
SO
Mosley
M J
MJ
Wilson
K H
KH
Worman
N P
NP
Campbell
S
S
Fidock
M D
MD
Furness
L M
LM
Parry-Smith
D J
DJ
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D006224:Cricetinae; D005796:Genes; D006801:Humans; D008969:Molecular Sequence Data; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000235:genetics*; D015290:Second Messenger Systems; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013329:Structure-Activity Relationship
D010716:Phosphatidylinositols; D011942:Receptors, Adrenergic, alpha