Cotterell D J, Munday K A, Poat J A
Biochem Pharmacol. 1984 Mar 1;33(5):751-6. doi: 10.1016/0006-2952(84)90458-1.
The binding of [3H]prazosin and [3H]clonidine to rat jejunal epithelial cell membranes has been studied. The membrane preparation was enriched in baso-lateral components as determined by Na+, K+ ATPase and alkaline phosphatase activities. The membranes possessed two saturable specific binding sites for [3H]prazosin, a high affinity (Kd 0.17 nM) low capacity (Bmax 27.3 fmole bound per mg protein) and a low affinity (Kd 5.0 nM) high capacity (Bmax 276 fmole bound per mg protein) site. The specificity of both sites was similar and was related to alpha 1-adrenoceptors. [3H]Clonidine bound to the membranes in a saturable fashion (Kd 7.3 nM). The specificity of this site was related to alpha 2-adrenoceptors. The [3H]clonidine binding site was present in the membranes in much lower density (Bmax 22.8 fmole bound per mg protein) suggesting that alpha 1-adrenoceptors predominate in this tissue.
已对[3H]哌唑嗪和[3H]可乐定与大鼠空肠上皮细胞膜的结合进行了研究。通过钠钾ATP酶和碱性磷酸酶活性测定，膜制剂富含基底外侧成分。这些膜对[3H]哌唑嗪具有两个可饱和的特异性结合位点，一个高亲和力（解离常数Kd为0.17 nM）低容量（每毫克蛋白质结合的最大结合量Bmax为27.3飞摩尔）位点和一个低亲和力（Kd为5.0 nM）高容量（每毫克蛋白质结合的Bmax为276飞摩尔）位点。两个位点的特异性相似，且与α1 -肾上腺素能受体有关。[3H]可乐定以可饱和方式与膜结合（Kd为7.3 nM）。该位点的特异性与α2 -肾上腺素能受体有关。[3H]可乐定结合位点在膜中的密度低得多（每毫克蛋白质结合的Bmax为22.8飞摩尔），表明α1 -肾上腺素能受体在该组织中占主导地位。
