Piwko C, Thoss V S, Probst A, Hoyer D
SANDOZ Pharma Ltd, Basel, Switzerland.
J Recept Signal Transduct Res. 1997 Jan-May;17(1-3):385-405. doi: 10.3109/10799899709036616.
The pharmacological profile and localization of somatostatin (SRIF) receptors were determined in rat, monkey and human cerebellum. In rat cerebellar cortex, low sst1/sst4, intermediate sst2 and very high sst3 receptor mRNA levels were found. sst1 mRNA was also expressed in the deep cerebellar nuclei. [125I]Tyr3-octreotide binding sites in cerebellar membranes correlated with recombinant sst2, but not with sst5 or sst3 receptors and were found in the molecular layer of the cerebellum. [125I]CGP 23996 (in Na(+)-buffer) binding in rat cerebellum correlated with sst1 or sst4, but not with sst2, sst3 or sst5 receptor binding. Similar data were obtained in rhesus monkey cerebellum. mRNAs for all five receptors were found in the granule cell layer of the human cerebellum and/or in the dentate nucleus. [125I]Tyr3-octreotide binding was strong in the molecular layer and correlated with that of recombinant sst2 receptors, but not with sst3 or sst5 receptors. [125I]CGP 23996 (in Mg(++)-buffer) binding was heterogeneous (about 75%, to sst2 and 25% to sst1 and/or sst4 receptors). The molecular and granular layers were equally and the dentate nucleus strongly labeled. Thus, SRIF receptors of the sst2, sst1 and/or sst4 subtype are presnt in the rat, monkey and human cerebellum. In the latter two species, the sst2 type appears to be predominant. Surprisingly, the high expression of sst3 receptor mRNA is not supported by radioligand binding data in any of the species studied. The reason for this discrepancy remains to be elucidated.
在大鼠、猴和人类小脑中测定了生长抑素（SRIF）受体的药理学特征和定位。在大鼠小脑皮质中，发现sst1/sst4受体mRNA水平较低，sst2受体mRNA水平中等，sst3受体mRNA水平非常高。sst1 mRNA也在小脑深部核团中表达。小脑膜中[125I]酪氨酰3-奥曲肽结合位点与重组sst2受体相关，但与sst5或sst3受体无关，且在小脑分子层中发现。大鼠小脑中[125I]CGP 23996（在Na(+)-缓冲液中）结合与sst1或sst4受体相关，但与sst2、sst3或sst5受体结合无关。在恒河猴小脑中获得了类似的数据。在人类小脑颗粒细胞层和/或齿状核中发现了所有五种受体的mRNA。[125I]酪氨酰3-奥曲肽在分子层中的结合很强，且与重组sst2受体的结合相关，但与sst3或sst5受体无关。[125I]CGP 23996（在Mg(++)-缓冲液中）结合是异质性的（约75%与sst2结合，25%与sst1和/或sst4受体结合）。分子层和颗粒层标记程度相同，齿状核标记强烈。因此，sst2、sst1和/或sst4亚型的SRIF受体存在于大鼠、猴和人类小脑中。在后两个物种中，sst2型似乎占主导地位。令人惊讶的是，在所研究的任何物种中，放射性配体结合数据均不支持sst3受体mRNA的高表达。这种差异的原因有待阐明。
