Fremeau R T, Jensen R T, Charlton C G, Miller R L, O'Donohue T L, Moody T W
J Neurosci. 1983 Aug;3(8):1620-5. doi: 10.1523/JNEUROSCI.03-08-01620.1983.
The binding of [125I]secretin to rat brain membranes was investigated. Radiolabeled secretin bound with high affinity (KD = 0.2 nM) to a single class of noninteracting sites. Binding was specific, saturable, and reversible. Regional distribution studies indicated that the specific binding was greatest in the cerebellum, intermediate in the cortex, thalamus, striatum, hippocampus, and hypothalamus, and lowest in the midbrain and medulla/pons. Pharmacological studies indicated that only secretin, but not other peptides, inhibits binding of [125I]secretin with high affinity. Also, certain guanine nucleotides inhibited high affinity binding. These data indicate that rat brain membranes possess high affinity binding sites specific for secretin and that with the use of [125I] secretin the kinetics, stoichiometry, specificity, and distribution of secretin receptors can be directly investigated.
研究了[125I]促胰液素与大鼠脑膜的结合情况。放射性标记的促胰液素以高亲和力（KD = 0.2 nM）结合到一类单一的非相互作用位点上。结合具有特异性、饱和性和可逆性。区域分布研究表明，特异性结合在小脑中最大，在皮质、丘脑、纹状体、海马体和下丘脑中居中，而在中脑和延髓/脑桥中最低。药理学研究表明，只有促胰液素，而不是其他肽，能以高亲和力抑制[125I]促胰液素的结合。此外，某些鸟嘌呤核苷酸也抑制高亲和力结合。这些数据表明，大鼠脑膜具有促胰液素特异性的高亲和力结合位点，并且使用[125I]促胰液素可以直接研究促胰液素受体的动力学、化学计量学、特异性和分布。
