Characterization of alpha 1-adrenoceptor subtypes in rat spinal cord.
The alpha 1-adrenoceptor subtypes in ventral and dorsal horns of rat lumbar spinal cord were studied. High concentrations of the alpha 1D-adrenoceptor antagonist, BMY 7378 (8-[2-[4-(2-methoxyphenyl) 1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride), displaced bound [3H]prazosin in a single-site manner and the binding affinity was close to those for alpha 1A- and alpha 1B-adrenoceptor binding sites. 5-Methyl-urapidil displaced bound [3H]prazosin in a two site manner and the high and low affinities were close to those of alpha 1A- and alpha 1B-adrenoceptor binding sites, respectively. The alpha 1-adrenoceptor subtype populations of ventral and dorsal horns did not differ. The alpha 1A- and alpha 1B-adrenoceptor populations comprised 70% and 30%, respectively, of the total and very few alpha 1D-adrenoceptors were detected.
Department of Pharmacy, Branch Hospital, Faculty of Medicine, University of Tokyo, Japan.
T
T
Wada
T
T
Otsu
Y
Y
Hasegawa
A
A
Mizuchi
H
H
Ono
D000818:Animals; D008297:Male; D010879:Piperazines / Q000378:metabolism / Q000494:pharmacology; D011224:Prazosin / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*
D010879:Piperazines; D018340:Receptors, Adrenergic, alpha-1; C053428:BMY 7378; D011224:Prazosin