High affinity quinuclidinyl benzilate binding to rat parotid membranes requires muscarinic receptor G proteins interactions

FEBS Letters

Ambudkar, Indu S.¹  Horn, Valerie J.¹  Baum, Bruce J.¹ 

[1] Clinical Investigations and Patient Care Branch, National Institute of Dental Research, NIH, Bldg. 10, Rm. 1N-113 Berthesda, MD 20892, USA

关键词: Antagonists;    Receptor;    G protein;    Parotid;    AIF− 4;    GTPγS;   

DOI  :  10.1016/0014-5793(91)80497-Q

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The binding of the non-selective muscarinic antagonists [³H] quinuclidinyl benzilate (QNB) to rat parotid membranes was characterized. Under equilibrium conditions. [³H]QNB bound to a homogenous population of muscarinic receptors (K_d . 118±19 pM; B _max 572±42 fmol/mg membrane protein. n = 12). The addition of G protein activators AIF⁻ ₄ or guanosine-5′-O-(3-thiotriphospate) (GTPγS) + Mg²⁺ increased the K _d by 77 ± 7% (n=4. P < 0.05) and 83 ± 27% (n=7, P < 0.05), respectively, without a change in the B _max or homogeneity of the binding site. GTPγS added without exogenous Mg²⁺ did not affect [³H] QNB binding requires a muscarinic receptor/G protein interaction.

【 授权许可】

Unknown