Theveniau M, Reisine T
Department of Pharmacology and Institute of Neurological Sciences, University of Pennsylvania School of Medicine, Philadelphia 19104.
J Neurochem. 1993 May;60(5):1870-5. doi: 10.1111/j.1471-4159.1993.tb13414.x.
The neuropeptide somatostatin (SRIF) exerts several important physiological actions in the adult CNS through interactions with membrane-bound receptors. SRIF expression is developmentally regulated and this regulation is most apparent in the cerebellum, where SRIF immunoreactivity is expressed at early postnatal ages and then disappears toward adulthood. The transitory nature of SRIF expression at a time of major changes in cerebellum suggests that this peptide may have a role in cerebellar development. To further investigate the role of the SRIF transmitter system during development, we have examined the levels of expression of SRIF receptors in the developing rat brain by immunoblotting using antiserum selective for a 60-kDa brain SRIF receptor. In whole rat brain, SRIF receptor immunoreactivity first appears at embryonic day 13 (E13), is elevated at E16, increases at birth, peaks at early postnatal ages, and then gradually declines with age. No apparent changes in size of the receptor occur with age. No consistent changes in levels of SRIF receptor immunoreactivity are detected from early postnatal ages to adulthood in the hippocampus, cerebral cortex, and striatum, but levels gradually decline in the hypothalamus. In contrast, SRIF receptor immunoreactivity is expressed transiently in cerebellum. SRIF receptor immunoreactivity is detectable in cerebellum at E16, increases in levels at birth, is apparent from postnatal day 3 to postnatal day 8, and then disappears. The transitory nature of SRIF receptor expression in cerebellum is unique and parallels the expression of SRIF immunoreactivity in this brain region. These findings support the hypothesis that SRIF has a role in cerebellar development.
神经肽生长抑素（SRIF）通过与膜结合受体相互作用，在成年中枢神经系统中发挥多种重要的生理作用。SRIF的表达受发育调控，这种调控在小脑中最为明显，在出生后早期小脑中表达SRIF免疫反应性，然后在成年期消失。在小脑发生重大变化时SRIF表达的短暂性表明，这种肽可能在小脑发育中起作用。为了进一步研究SRIF递质系统在发育过程中的作用，我们使用对60 kDa脑SRIF受体具有选择性的抗血清，通过免疫印迹法检测了发育中大鼠脑内SRIF受体的表达水平。在整个大鼠脑中，SRIF受体免疫反应性首先出现在胚胎第13天（E13），在E16时升高，出生时增加，在出生后早期达到峰值，然后随着年龄增长逐渐下降。受体大小未随年龄出现明显变化。从出生后早期到成年期，在海马体、大脑皮层和纹状体中未检测到SRIF受体免疫反应性水平的一致变化，但在下丘脑中水平逐渐下降。相比之下，SRIF受体免疫反应性在小脑中短暂表达。在E16时可在小脑中检测到SRIF受体免疫反应性，出生时水平增加，在出生后第3天至第8天明显，然后消失。小脑中SRIF受体表达的短暂性是独特的，与该脑区SRIF免疫反应性的表达平行。这些发现支持了SRIF在小脑发育中起作用的假说。
