Nirenberg M J, Tate S S, Mosckovitz R, Udenfriend S, Pickel V M
Department of Neurology, Cornell University Medical College, New York, New York 10021, USA.
J Comp Neurol. 1995 Jun 12;356(4):505-22. doi: 10.1002/cne.903560403.
A neutral and basic amino acid transporter (NBAT) cloned from rat kidney was recently localized to enteroendocrine cells and enteric neurons. We used an antibody directed against a synthetic peptide representing a putative extracellular domain of NBAT to determine whether this transporter was also present in other endocrine and neural tissues, including rat adrenal gland, brainstem, and spinal cord. Abundant, highly granular labeling for NBAT was observed in the cytoplasm of chromaffin and ganglion cells in the adrenal medulla. A small population of intensely labeled varicose processes was also seen in both the cortex and the medulla of the adrenal gland. More numerous, intensely labeled varicose processes were detected in brainstem and spinal cord nuclei, including the locus coeruleus, rostral ventrolateral medulla, nuclei of the solitary tract, dorsal motor nucleus of the vagus, and intermediolateral cell column of the thoracic spinal cord. Significant perikaryal labeling for NBAT was only detected in brainstem and spinal cord following intraventricular colchicine treatment, which increased the number, distribution, and intensity of NBAT-immunolabeled cells. These NBAT-immunoreactive perikarya were most numerous in the locus coeruleus, rostral ventrolateral medulla, nuclei of the solitary tract, and raphe nuclei. Ultrastructural examination of the nuclei of the solitary tract of normal rats showed that NBAT was localized predominantly to axon terminals. Within these labeled terminals, NBAT was associated with large dense core vesicles and discrete segments of plasma membrane. The observed localization of NBAT suggests that this renal specific amino acid transporter subserves a role as a vesicular or plasmalemmal transporter in monoamine-containing cells, including chromaffin cells and autonomic neurons.
最近从大鼠肾脏克隆出的一种中性和碱性氨基酸转运体（NBAT）定位于肠内分泌细胞和肠神经元。我们使用一种针对代表NBAT假定细胞外结构域的合成肽的抗体，来确定这种转运体是否也存在于其他内分泌和神经组织中，包括大鼠肾上腺、脑干和脊髓。在肾上腺髓质的嗜铬细胞和神经节细胞的细胞质中观察到丰富的、高度颗粒状的NBAT标记。在肾上腺皮质和髓质中也可见少量强标记的曲张突起。在脑干和脊髓核中检测到更多数量、强标记的曲张突起，包括蓝斑、延髓头端腹外侧、孤束核、迷走神经背运动核和胸段脊髓中间外侧细胞柱。仅在脑室内注射秋水仙碱处理后的脑干和脊髓中检测到NBAT的明显核周标记，这增加了NBAT免疫标记细胞的数量、分布和强度。这些NBAT免疫反应性核周体在蓝斑、延髓头端腹外侧、孤束核和中缝核中最多。对正常大鼠孤束核的超微结构检查表明，NBAT主要定位于轴突终末。在这些标记的终末内，NBAT与大的致密核心囊泡和质膜的离散片段相关。观察到的NBAT定位表明，这种肾脏特异性氨基酸转运体在含单胺的细胞中，包括嗜铬细胞和自主神经元中，作为囊泡或质膜转运体发挥作用。
