Selective interaction of DG-5128 with a low agonist affinity state of alpha-2 adrenoceptor.
Using rat cerebral cortex membranes, the inhibitory effect of DG-5128 against (3H)-clonidine binding was compared between low (alpha 2L) (in the presence of EDTA) and high (alpha 2H) affinity states (in the presence of excess magnesium) of alpha 2-adrenoceptor for agonists. The Ki value (pKi=6.79) of DG-5128 in the alpha 2L state was 6.4 times higher than the value in the alpha 2H state. Thus, DG-5128 produces alpha 2-adrenoceptor antagonism through the selective interaction with an alpha 2L state of the receptor.
Yamanaka
K
K
Kigoshi
S
S
Muramatsu
I
I
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects* / Q000378:metabolism; D015016:Yohimbine / Q000494:pharmacology
D007004:Hypoglycemic Agents; D007093:Imidazoles; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; C032368:midaglizole; D003000:Clonidine