Nonomura K, Tooyama I, Abe H, Renda T, Erspamer V, Shimada M, Kimura H
Institute of Molecular Neurobiology, Shiga University of Medical Science, Otsu, Japan.
J Comp Neurol. 1994 Nov 8;349(2):223-43. doi: 10.1002/cne.903490206.
[D-Ala2]deltorphin-I, a highly selective ligand for delta opioid receptors, is a heptapeptide originally purified from frog skin. Previous immunohistochemical studies indicate that [D-Ala2]deltorphin-I-like molecule(s) may be present in adult rat brain, including specific neuronal cells and fibers partially overlapping with the mesocortical and nigrostriatal dopaminergic systems. Here, we examined the developmental aspect of such immunoreactive brain structures in early postnatal rats. In newborn to 21-day-old rats, positive staining in the brain occurred mainly in subpopulations of neurons and occasionally in tanycytes. On postnatal day 0, neuronal cell bodies containing [D-Ala2]deltorphin-I-like immunoreactivity were found in various brain regions, including the olfactory tubercle, ventral pallidum, hippocampus, ventral tegmental area, pars compacta of the substantia nigra, supramammillary nucleus, and dorsal raphe nucleus. Immunoreactive nerve fibers were observed in the main and accessory olfactory bulbs, olfactory tubercle, prelimbic area, anterior cingulate cortex, neostriatum, accumbens, lateral septal nucleus, lateral habenular nucleus, and superior colliculus. As pups grew, positive staining of cell bodies decreased gradually in both density and intensity, and those in the olfactory tubercle and ventral pallidum were no longer visible on postnatal day 14. On postnatal day 21, positive cells were found only in the ventral midbrain, including the pars compacta of the substantia nigra, ventral tegmental area, A8 region, and supramammillary nucleus. Positive fibers also decreased in density with age except in the accessory olfactory bulb, olfactory tubercle, prelimbic area, and anterior cingulate cortex.
[D - Ala2]强啡肽 - I是一种对δ阿片受体具有高度选择性的配体，是最初从蛙皮中纯化出来的七肽。先前的免疫组织化学研究表明，[D - Ala2]强啡肽 - I样分子可能存在于成年大鼠脑中，包括与中脑皮质和黑质纹状体多巴胺能系统部分重叠的特定神经元细胞和纤维。在此，我们研究了新生大鼠早期此类免疫反应性脑结构的发育情况。在新生至21日龄的大鼠中，脑中的阳性染色主要出现在神经元亚群中，偶尔也出现在伸长细胞中。出生后第0天，在包括嗅结节、腹侧苍白球、海马体、腹侧被盖区、黑质致密部、乳头体上核和中缝背核在内的各个脑区发现了含有[D - Ala2]强啡肽 - I样免疫反应性的神经元细胞体。在主嗅球和副嗅球、嗅结节、前边缘区、前扣带回皮质、新纹状体、伏隔核、外侧隔核、外侧缰核和上丘中观察到免疫反应性神经纤维。随着幼崽的成长，细胞体的阳性染色在密度和强度上逐渐降低，嗅结节和腹侧苍白球中的阳性染色在出生后第14天不再可见。在出生后第21天，仅在腹侧中脑发现阳性细胞，包括黑质致密部、腹侧被盖区、A8区和乳头体上核。除副嗅球、嗅结节、前边缘区和前扣带回皮质外，阳性纤维的密度也随年龄增长而降低。
