Malitschek B, Rüegg D, Heid J, Kaupmann K, Bittiger H, Fröstl W, Bettler B, Kuhn R
TA Nervous System, Novartis Pharma AG, Basel, CH-4002, Switzerland.
Mol Cell Neurosci. 1998 Sep;12(1-2):56-64. doi: 10.1006/mcne.1998.0698.
Recently, two N-terminal splice variants of the metabotropic receptor for GABA (gamma-amino-butyric acid) were cloned. Here, we describe an antiserum that recognizes the two receptor variants. We demonstrate that these proteins are identical with GABAB receptors that are photoaffinity labeled with [125I]CGP71872 in rat brain. The C-terminal epitopes recognized by the antiserum are conserved in several vertebrate species but not in chicken. No hints for the existence of additional closely related receptor subtypes or variants are found in double-labeling experiments with antibody and photoaffinity ligand. Western blot analysis reveals widespread expression of the GABABR1 receptor proteins in rat brain with the highest level of expression at early postnatal stages. The binding affinity of the GABAB receptor agonist L-baclofen at native R1a and R1b variants is similar. In early postnatal development the affinity at R1a and R1b is 10-fold lower than in adult brain and gradually increases with aging.
最近，γ-氨基丁酸（GABA）代谢型受体的两种N端剪接变体被克隆出来。在此，我们描述了一种能识别这两种受体变体的抗血清。我们证明，这些蛋白质与在大鼠脑中用[125I]CGP71872进行光亲和标记的GABAB受体相同。抗血清识别的C端表位在几种脊椎动物物种中保守，但在鸡中不保守。在抗体和光亲和配体的双重标记实验中，未发现存在其他密切相关的受体亚型或变体的迹象。蛋白质印迹分析显示，GABABR1受体蛋白在大鼠脑中广泛表达，在出生后早期阶段表达水平最高。GABAB受体激动剂L-巴氯芬对天然R1a和R1b变体的结合亲和力相似。在出生后早期发育阶段，R1a和R1b的亲和力比成年脑中低10倍，并随着年龄增长而逐渐增加。
