von Dalnok G K, Menssen H D
Anat Embryol (Berl). 1986;174(3):307-19. doi: 10.1007/BF00698781.
The postnatal differentiation of carotid body chief cells and endocrine adrenal medullary cells was comparatively examined during ontogenesis and in rats which were treated with dexamethasone for 7 days after birth. Ultrastructure and innervation of carotid body chief cells are mature in neonates according to the functional requirements of chemoreception. By the end of the first postnatal week, only an increase in number of dense core vesicles can be noticed, the concentration of which then will reach the adult level. Under the effect of dexamethasone most of the heterochromatin is transformed into finely dispersed euchromatin within the nuclei of carotid body chief cells. In the cytoplasm, the Golgi apparatus becomes larger and the granular endoplasmic reticulum hypertrophic. The number of catecholamines storing dense core vesicles increases considerably. The innervation density remains constant. In contrast to the carotid body chief cells, the adrenal medullary cells have not reached their definitive maturity at the time of birth. Besides phenotypes of adrenaline-cells, noradrenaline-cells and small granules containing cells, pheochromoblasts and intermediary cells can be seen as well. Their cytoplasm is sparse, the concentration of dense core vesicles and the innervation density very low. After 8 days of postnatal ontogenesis, pheochromoblasts and intermediary cells are no longer present in the adrenal medulla. In adrenaline-cells and noradrenaline-cells, important processes of growth can be noticed, the cytoplasm has grown in extent, the number of dense core vesicles doubled and the innervation density of single cells triplicated. Only the few small granules containing cells remain small. Under the effect of dexamethasone also in the nuclei of chromaffin cells a transformation of heterochromatin into euchromatin occurs. The increase in number of dense core vesicles is relatively lower than in carotid body chief cells. The significant growth of innervation density during the first postnatal week was inhibited. Our observations suggest that dexamethasone stimulates the synthesis of catecholamines in adrenal medullary cells of newborn rats less pronouncedly than in carotid body chief cells. This could be attributed to the inhibited formation of synapses of growing chromaffin cells and to the in vivo active endocrine counter-regulation.
在个体发育过程中以及出生后用 dexamethasone 处理 7 天的大鼠中，对颈动脉体主细胞和内分泌肾上腺髓质细胞的产后分化进行了比较研究。根据化学感受的功能需求，新生大鼠颈动脉体主细胞的超微结构和神经支配已成熟。在出生后第一周结束时，只能注意到致密核心囊泡数量增加，其浓度随后将达到成年水平。在 dexamethasone 的作用下，颈动脉体主细胞核内的大部分异染色质转化为精细分散的常染色质。在细胞质中，高尔基体变大，粗面内质网肥大。储存儿茶酚胺的致密核心囊泡数量显著增加。神经支配密度保持不变。与颈动脉体主细胞不同，肾上腺髓质细胞在出生时尚未达到最终成熟。除了肾上腺素细胞、去甲肾上腺素细胞和含小颗粒细胞的表型外，还可以看到嗜铬母细胞和中间细胞。它们的细胞质稀疏，致密核心囊泡浓度和神经支配密度非常低。出生后 8 天的个体发育后，嗜铬母细胞和中间细胞不再出现在肾上腺髓质中。在肾上腺素细胞和去甲肾上腺素细胞中，可以注意到重要的生长过程，细胞质范围增大，致密核心囊泡数量翻倍，单细胞的神经支配密度增加两倍。只有少数含小颗粒细胞仍然很小。在 dexamethasone 的作用下，嗜铬细胞的细胞核中也发生了异染色质向常染色质的转化。致密核心囊泡数量的增加相对低于颈动脉体主细胞。出生后第一周神经支配密度的显著增长受到抑制。我们的观察结果表明，dexamethasone 对新生大鼠肾上腺髓质细胞中儿茶酚胺合成的刺激作用不如对颈动脉体主细胞明显。这可能归因于生长中的嗜铬细胞突触形成的抑制以及体内活跃的内分泌反调节。
