Further evidence that the classical alpha 1A- and cloned alpha 1c-adrenoceptors are the same subtype.
We compared the inactivation of [3H]prazosin binding sites in membrane preparations of cell-lines expressing the cloned alpha 1b, alpha 1c and alpha 1d-adrenoceptors after pretreatment with the alkylating agents, 10 microM chlorethylclonidine or 10 nM SZL-49 (1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-bicyclo[2.2.2]octa- 2,5-diene-Z-carbonyl)-piperazine). The cloned alpha 1b-adrenoceptor exhibited a similar inactivation profile to that of the classical alpha 1B-adrenoceptor of rat liver in that chlorethylclonidine in contrast to SZL-49 produced a marked degree of inactivation. A similarity between the cloned alpha 1c-adrenoceptor and the classical alpha 1A-adrenoceptor of rat submaxillary gland was also noted in that both subtypes were highly sensitive to SZL-49 but relatively insensitive to chlorethylclonidine. The cloned alpha 1d-adrenoceptor displayed a unique profile in that both chlorethylclonidine and SZL-49 produced a marked inactivation of this subtype. The similarity of the alkylation-inactivation profiles between the cloned alpha 1c and classical alpha 1A-adrenoceptors support the recent proposal that these two alpha 1-adrenoceptors in fact correspond to the same subtype.
Pimoule
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C
Synthélabo Recherche, Rueil Malmaison, France.
Langer
S Z
SZ
Graham
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D
D000818:Animals; D001665:Binding Sites; D002417:Cattle; D003000:Clonidine / Q000031:analogs & derivatives / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D011224:Prazosin / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000145:classification*; D011994:Recombinant Proteins / Q000378:metabolism
D018340:Receptors, Adrenergic, alpha-1; D011994:Recombinant Proteins; C051307:SZL 49; C051731:chlorethylclonidine; D003000:Clonidine; D011224:Prazosin