TY - JOUR
T1 - Cloning, expression, and tissue distribution of the rat homolog of the bovine α1C-adrenergic receptor provide evidence for its classification as the α1A subtype
AU - Perez, Dianne M.
AU - Piascik, Michael T.
AU - Malik, Niveen
AU - Gaivin, Robert
AU - Graham, Robert M.
PY - 1994/11
Y1 - 1994/11
N2 - Three α1-adrenergic receptors (ARs) have been cloned, i.e., the α1B-, α1C-, and α1D-ARs. Compared with the α1B subtype, the α1A subtype in tissue is described as being insensitive to chloroethylclonidine and sensitive to SZL-49 and having a 10-100-fold higher affinity for a number of agonists and antagonists. The α1A subtype is also expressed in a variety of rat tissues (as assessed by pharmacology), with greatest abundance in the cerebral cortex, hippocampus, vas deferens, and submaxillary gland. The cloned bovine α1C-AR, though having an α1A-AR pharmacology, was first reported as not being expressed in any rat tissue (as determined by Northern analysis) and was therefore designated as a new subtype. We report the cloning, expression, and characterization of the rat homolog of the bovine α1C-AR. Using a human α1C-AR probe obtained by polymerase chain reaction screening of a neuroblastoma cell line (SK-N-MC), both exon 1 and exon 2 of the rat α1C-AR gene were cloned from a rat genomic library. These two exons were spliced together and cloned into the expression vector pMT2′. Transfection into COS-1 cells and analysis of the ligand-binding profile of the expressed protein receptor using 125I-HEAT revealed a 10-100-fold higher affinity for the α1-AR antagonists 5-methylurapidil, (+)-niguldipine, WB-4101, and phentolamine and the agonists oxymetazoline and methoxamine, compared with the α1B-AR. This ligand-binding profile is similar to that for endogenously expressed tissue α1A-ARs. In addition, the rat α1C-AR was the least sensitive of the three cloned subtypes to the alkylating effects of chloroethylclonidine but was the most sensitive to the alkylating prazosin analog SZL-49, properties also observed for the tissue α1A subtype. Furthermore, by three different techniques, i.e., RNase protection assays, reverse transcription-polymerase chain reaction Northern blotting, and in situ hybridization histochemistry, the rat α1C-AR mRNA was localized to α1A-AR-rich tissues, such as rat vas deferens, hippocampus, aorta, and submaxillary gland. Taken together, these data suggest that this receptor may actually represent the α1A subtype.
AB - Three α1-adrenergic receptors (ARs) have been cloned, i.e., the α1B-, α1C-, and α1D-ARs. Compared with the α1B subtype, the α1A subtype in tissue is described as being insensitive to chloroethylclonidine and sensitive to SZL-49 and having a 10-100-fold higher affinity for a number of agonists and antagonists. The α1A subtype is also expressed in a variety of rat tissues (as assessed by pharmacology), with greatest abundance in the cerebral cortex, hippocampus, vas deferens, and submaxillary gland. The cloned bovine α1C-AR, though having an α1A-AR pharmacology, was first reported as not being expressed in any rat tissue (as determined by Northern analysis) and was therefore designated as a new subtype. We report the cloning, expression, and characterization of the rat homolog of the bovine α1C-AR. Using a human α1C-AR probe obtained by polymerase chain reaction screening of a neuroblastoma cell line (SK-N-MC), both exon 1 and exon 2 of the rat α1C-AR gene were cloned from a rat genomic library. These two exons were spliced together and cloned into the expression vector pMT2′. Transfection into COS-1 cells and analysis of the ligand-binding profile of the expressed protein receptor using 125I-HEAT revealed a 10-100-fold higher affinity for the α1-AR antagonists 5-methylurapidil, (+)-niguldipine, WB-4101, and phentolamine and the agonists oxymetazoline and methoxamine, compared with the α1B-AR. This ligand-binding profile is similar to that for endogenously expressed tissue α1A-ARs. In addition, the rat α1C-AR was the least sensitive of the three cloned subtypes to the alkylating effects of chloroethylclonidine but was the most sensitive to the alkylating prazosin analog SZL-49, properties also observed for the tissue α1A subtype. Furthermore, by three different techniques, i.e., RNase protection assays, reverse transcription-polymerase chain reaction Northern blotting, and in situ hybridization histochemistry, the rat α1C-AR mRNA was localized to α1A-AR-rich tissues, such as rat vas deferens, hippocampus, aorta, and submaxillary gland. Taken together, these data suggest that this receptor may actually represent the α1A subtype.
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M3 - Article
C2 - 7969068
AN - SCOPUS:0028061920
SN - 0026-895X
VL - 46
SP - 823
EP - 831
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 5
ER -