Home
Resources
Publications
Characterization of the Alpha 1A-adrenoceptors of Guinea Pig Liver Membranes: Studies Using 5-[3H]methylurapidil

Characterization of the Alpha 1A-adrenoceptors of Guinea Pig Liver Membranes: Studies Using 5-[3H]methylurapidil

J A García-Sáinz, M T Romero-Avila

Mol Pharmacol. 1993 Sep;44(3):589-94.

PMID: 8396719

Abstract:

Binding of 5-[3H]methylurapidil to guinea pig liver membranes was rapid, saturable, and reversible. Scatchard analysis of saturation isotherms indicated a single class of binding sites with a Kd of 0.86 nM and a Bmax of 36 fmol/mg of protein. Preincubation of the membranes with chlorethylclonidine did not alter significantly the binding parameters for 5-[3H]methylurapidil. Binding competition experiments were performed, and the order of potency for agonists was oxymetazoline > epinephrine > norepinephrine >> methoxamine; for antagonists, the potency order was (+)-niguldipine > or = 5-methylurapidil = prazosin = WB4101 > benoxathian > or = phentolamine > or = (-)-niguldipine. The binding affinity for epinephrine was modulated by the hydrolysis-resistant GTP analogue guanosine-5'-(beta, gamma-imido)triphosphate. The pharmacological profile of the 5-[3H]methylurapidil binding sites of guinea pig liver differs markedly from those of the cloned alpha 1-adrenoceptors (i.e., alpha 1B-, alpha 1C-, and alpha 1A/D-adrenoceptors) and resembles that of the classical alpha 1A receptor subtype.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP34661853	5-Methylurapidil		34661-85-3	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: