5-Methylurapidil may discriminate between alpha 1-adrenoceptors with a high affinity for WB4101 in rat lung.
The alpha 1-adrenoceptors of rat lung with a high affinity for [3H]-prazosin were subdivided into two populations (high and low affinity sites) by WB4101 and 5-methylurapidil but the proportions were different between both drugs. After pretreatment with chlorethylclonidine, WB4101 recognized only high affinity sites, while 5-methylurapidil still detected high and low affinity sites. These results indicate that alpha 1-adrenoceptors with a high affinity for WB4101 are not homogeneous in the rat lung, suggesting the possible existence of a new alpha 1-adrenoceptor subtype in addition to alpha 1A and alpha 1B subtypes.
Department of Second Surgery, Fukui Medical School, Japan.
Y
Y
Hiramatsu
R
R
Muraoka
S
S
Kigoshi
I
I
Muramatsu
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism*; D000818:Animals; D001667:Binding, Competitive / Q000502:physiology; D004146:Dioxanes / Q000494:pharmacology*; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D010879:Piperazines / Q000378:metabolism*; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000378:metabolism
D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D010879:Piperazines; D011942:Receptors, Adrenergic, alpha; C057446:5-methylurapidil; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D011224:Prazosin