Ewa Badowska-Szalewska, Beata Ludkiewicz, Ilona Klejbor, Dariusz Świetlik, Janusz Moryś
Department of Anatomy and Neurobiology, Medical University of Gdańsk, ul. Dębinki 1, 80-211 Gdańsk, Poland.
Int J Dev Neurosci. 2012 Apr;30(2):139-46. doi: 10.1016/j.ijdevneu.2011.12.001. Epub 2011 Dec 9.
The type and duration of stress stimulation are postulated to affect the expression of the brain derived neurotrophic factor (BDNF) differentially during ontogenetic life. The aim of our study was to investigate the influence of two different stressors, i.e. chronic (15 min daily for 21 days) exposure to the forced swim (FS) test or the high light open field (HL-OF) test, on the BDNF contained in magnocellular (PVm) and parvocellular (PVp) neurons of the hypothalamic paraventricular (PV) and the supraoptic (SO) nuclei. The immunofluorescence (-ir) method was used to detect BDNF-ir cells. The research showed that only the PVp part of the PV in juvenile (P28; P-postnatal day) control rats had a significantly lower density of BDNF-ir neurons than that in middle-aged (P360) control subjects. After chronic FS, a significant decrease in BDNF-ir cells was observed in the studied hypothalamic nuclei of the juvenile rats, but no changes were noted in the middle-aged individuals. The PV (PVm, PVp) and the SO nuclei in juvenile rats showed a significantly lower density of BDNF-ir neurons than the corresponding area of the hypothalamus in middle-aged rats. However, following the HL-OF test, the density of BDNF-ir neurons remained unaltered both in the P28 and the P360 groups. The data suggest that the type of the stressor applied was the factor that differentiated the number of BDNF-ir cells in the PVm and the SO only in juvenile rats: chronic HL-OF was more severe than FS. The age of the animals was the main factor that conditioned the BDNF hypothalamic PV (PVm, PVp) and the SO response to FS stimulation. The different density of BDNF-ir containing cells in the PVp of juvenile versus middle-aged rats can be explained by a functional, age-related change in the demand of PVp neurons for BDNF.
据推测，应激刺激的类型和持续时间在个体发育过程中会对脑源性神经营养因子（BDNF）的表达产生不同影响。我们研究的目的是调查两种不同应激源，即慢性（每天15分钟，持续21天）暴露于强迫游泳（FS）试验或强光旷场（HL-OF）试验，对下丘脑室旁核（PV）和视上核（SO）的大细胞（PVm）和小细胞（PVp）神经元中所含BDNF的影响。采用免疫荧光（-ir）法检测BDNF-ir细胞。研究表明，仅幼年（出生后第28天；P-出生后天数）对照大鼠PV的PVp部分中BDNF-ir神经元的密度显著低于中年（出生后第360天）对照大鼠。慢性FS后，在幼年大鼠的研究下丘脑核中观察到BDNF-ir细胞显著减少，但中年个体未观察到变化。幼年大鼠的PV（PVm、PVp）和SO核中BDNF-ir神经元的密度显著低于中年大鼠下丘脑的相应区域。然而，在HL-OF试验后，P28组和P360组中BDNF-ir神经元的密度均未改变。数据表明，所施加应激源的类型是仅在幼年大鼠中区分PVm和SO中BDNF-ir细胞数量的因素：慢性HL-OF比FS更严重。动物的年龄是调节BDNF在下丘脑PV（PVm、PVp）和SO对FS刺激反应的主要因素。幼年大鼠与中年大鼠PVp中含BDNF-ir细胞的不同密度可通过PVp神经元对BDNF需求的功能性、与年龄相关的变化来解释。
