Faucher D J, Evans P J, Khurana R, Miller M M
Department of Obstetrics and Gynecology, McGill University, Montreal, Que., Canada.
Acta Anat (Basel). 1994;149(4):279-90. doi: 10.1159/000147589.
Arginine vasopressin (AVP) is a peptide hormone which is found in neurons within the paraventricular (PVN) and the supraoptic (SON) nuclei of the hypothalamus. In fetal sheep, this neuropeptide is involved in maturational processes and adaptive responses to 'stress'. This study examined the effect of age on the total number and distribution of AVP-containing neurons in the PVN and SON of fetal sheep and newborn lambs by quantitative light-microscopic immunocytochemistry. Serial coronal sections of hypothalami from three groups of animals were studied: fetuses at 104-109 days of gestation (n = 6) comprising the early group, fetuses at 130-139 days of gestation (n = 5) comprising the late group and newborn lambs at 12-20 postnatal days (n = 5) comprising the neonatal group. This period of development was chosen since adaptive mechanisms to stress are operative at or near the time of birth. Hypothalamic dimensions were measured to determine if maturation had an effect on the size of the AVP-containing subregions of the hypothalamus during this period of development. Dimensions included: ventricle height, optic chiasm width, distances from the dorsal margin of the ventricle to the lateral and medial margins of the optic tract, and distance between the medial margins of the optic tracts. As expected, with increase in maturational age, overall dimensions of the AVP-containing subregions increased significantly (p < 0.05). When early- and late-gestation fetuses were compared to newborn lambs, there was a significant increase in the total number of immunoreactive neurons in both the PVN (p < 0.01, Anova) and SON (p < 0.001, Anova) with age. With advancing age, we also observed an increase in the density of AVP neurons in the middle subregion of the PVN and in the midrostral subregion of the SON. These data suggest that, during the late gestational and early postnatal period, de novo synthesis of AVP genes occurs in these hypothalamic nuclei. This study provides a baseline for further investigation to study the effects of stress on these neurons in the developing ovine fetus and newborn lamb.
精氨酸加压素（AVP）是一种肽类激素，在下丘脑室旁核（PVN）和视上核（SON）的神经元中发现。在胎羊中，这种神经肽参与成熟过程以及对“应激”的适应性反应。本研究通过定量光学显微镜免疫细胞化学方法，研究了年龄对胎羊和新生羔羊PVN和SON中含AVP神经元总数及分布的影响。研究了三组动物下丘脑的连续冠状切片：妊娠104 - 109天的胎儿（n = 6）为早期组，妊娠130 - 139天的胎儿（n = 5）为晚期组，出生后12 - 20天的新生羔羊（n = 5）为新生组。选择这个发育阶段是因为对应激的适应性机制在出生时或接近出生时起作用。测量下丘脑尺寸以确定在此发育阶段成熟是否对下丘脑含AVP亚区域的大小有影响。尺寸包括：脑室高度、视交叉宽度、从脑室背缘到视束外侧和内侧边缘的距离以及视束内侧边缘之间的距离。正如预期的那样，随着成熟年龄的增加，含AVP亚区域的整体尺寸显著增加（p < 0.05）。将妊娠早期和晚期胎儿与新生羔羊进行比较时，PVN（p < 0.01，方差分析）和SON（p < 0.001，方差分析）中免疫反应性神经元的总数均随年龄显著增加。随着年龄的增长，我们还观察到PVN中间亚区域和SON中 Rostral 亚区域的AVP神经元密度增加。这些数据表明，在妊娠后期和出生后早期，这些下丘脑核中发生了AVP基因的从头合成。本研究为进一步研究应激对发育中的绵羊胎儿和新生羔羊这些神经元的影响提供了基线。
