大鼠大脑皮质膜中[125I]热与α1-肾上腺素能受体结合的阳离子敏感性
Cation sensitivity of [125I]heat binding to alpha 1-adrenoceptors in rat cerebral cortex membranes.
作者信息
Glossmann H, Lübbecke F, Bellemann P, Presek P
出版信息
Eur J Pharmacol. 1981 Oct 22;75(2-3):149-53. doi: 10.1016/0014-2999(81)90076-5.
The alpha 1-adrenoceptor antagonist 2-[beta-(4-hydroxyphenyl)-ethylaminomethyl] tetralone (HEAT) was radiolabeled with 125I and purified to the maximal specific radioactivity of 2200 Ci/mmol. [125 I]HEAT selectively labels alpha 1-adrenoceptors (KD approximately 0.1 nM at 30 degrees C) in rat cerebral cortex membranes. Divalent cations stimulated [125 I]HEAT binding to the alpha 1-adrenoceptors. The rank order of potencies was Ni2+ greater than Mn2+ greater than Mg2+ greater than Ca2+ approximately Sr2+. The effect of Mg2+ was mainly on the Bmax of the alpha I-adrenoceptors. Monovalent cations also stimulated [125I]HEAT binding. Maximal stimulation (up to 3-fold) was seen with Na+ (optimal concentration at approximately 150 mM). Li+ and NH4+ were less effective whereas K+ was ineffective. The stimulation of [125I]HEAT binding to alpha I-adrenoceptors by Na+ was temperature-dependent.
α1 -肾上腺素能受体拮抗剂2 - [β - (4 -羟苯基)-乙氨基甲基]四氢萘酮（HEAT）用125I进行放射性标记，纯化至最大比放射性为2200 Ci/mmol。[125I]HEAT能选择性地标记大鼠大脑皮层膜中的α1 -肾上腺素能受体（30℃时KD约为0.1 nM）。二价阳离子能刺激[125I]HEAT与α1 -肾上腺素能受体的结合。其效力顺序为Ni2+＞Mn2+＞Mg2+＞Ca2+≈Sr2+。Mg2+的作用主要体现在α1 -肾上腺素能受体的Bmax上。单价阳离子也能刺激[125I]HEAT的结合。Na+能产生最大刺激（高达3倍）（最佳浓度约为150 mM）。Li+和NH4+的效果较差，而K+则无效。Na+对[125I]HEAT与α1 -肾上腺素能受体结合的刺激作用具有温度依赖性。
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