Hashimoto H, Marystone J F, Greenough W T, Bohn M C
Department of Psychology, University of Illinois, Urbana-Champaign 61820.
Exp Neurol. 1989 Apr;104(1):62-7. doi: 10.1016/0014-4886(89)90009-5.
Alterations in glucocorticoid hormones are known to affect the development of brain and behavior, but the details of these effects at the cellular level are unclear. The present study was undertaken to determine whether dendritic growth and branching in glucocorticoid target neurons, the granule neurons of the hippocampal dentate gyrus, are affected by glucocorticoid hormones. Computerized morphometric analysis of Golgi impregnated granule cells showed that adrenalectomy on Postnatal Day 21 resulted in a small decrease in dendritic branching of lower order dendrites in both male and female rats at 42 days of age, while branching of distal dendrites was left unaffected. Conversely, dendritic branching in rats treated daily with hydrocortisone acetate (5 mg/kg) during the same period was not significantly different from that of untreated rats. Total dendritic length was unaffected by either treatment. These results suggest that relatively minor alterations may occur in the circuitry in the inner molecular layer of the dentate gyrus, a region involving intrahippocampal connections, in the absence of physiological levels of glucocorticoid hormones. Whether these effects are mediated via glucocorticoid hormone effects on the presynaptic afferent neurons or via granule cell metabolic pathways remains to be determined. The most surprising result, given the presence of glucocorticoid receptors in granule cells and the relatively dramatic effects of glucocorticoid manipulations on whole brain that have been reported, is that the effects of these manipulations on dendritic morphology are minimal.(ABSTRACT TRUNCATED AT 250 WORDS)
已知糖皮质激素的改变会影响大脑发育和行为，但这些影响在细胞水平的细节尚不清楚。本研究旨在确定糖皮质激素是否会影响糖皮质激素靶神经元（海马齿状回颗粒神经元）的树突生长和分支。对高尔基染色的颗粒细胞进行计算机形态计量分析表明，出生后第21天进行肾上腺切除术，导致42日龄的雄性和雌性大鼠较低级树突的树突分支略有减少，而远端树突的分支未受影响。相反，在此期间每天用醋酸氢化可的松（5毫克/千克）治疗的大鼠的树突分支与未治疗的大鼠没有显著差异。两种处理对树突总长度均无影响。这些结果表明，在缺乏生理水平糖皮质激素的情况下，齿状回内分子层（涉及海马内连接的区域）的神经回路可能会发生相对较小的改变。这些影响是通过糖皮质激素对突触前传入神经元的作用还是通过颗粒细胞代谢途径介导的，仍有待确定。鉴于颗粒细胞中存在糖皮质激素受体，以及已报道的糖皮质激素操作对全脑的相对显著影响，最令人惊讶的结果是，这些操作对树突形态的影响很小。（摘要截断于250字）
