Jhamandas J H, MacTavish D
Division of Neurology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
J Neuroendocrinol. 2003 Jan;15(1):24-32. doi: 10.1046/j.1365-2826.2003.00869.x.
Neuropeptide FF (NPFF), a morphine modulatory peptide, is emerging as an important neuromodulator in the context of central autonomic and neuroendocrine regulation. NPFF immunoreactivity and receptors have been identified in discrete autonomic regions within the brain and spinal cord, including the hypothalamic paraventricular nucleus (PVN). In this study, we examined the effects of intracerebroventricular (i.c.v.) administration of NPFF on activation of chemically identified PVN neurones that project to the brainstem nucleus of the solitary tract (NTS). In conscious rats, i.c.v. NPFF at a dose of 10 micro g, but not 8 micro g, caused an increase in arterial blood pressure. Immunohistochemical analysis revealed a dose-dependent increase in activated (Fos positive) PVN neurones following i.c.v. NPFF administration compared to controls receiving i.c.v. saline. Activated PVN neurones were located predominantly in the parvocellular compartment of the nucleus with relatively few Fos positive cells in the magnocellular subdivision. Chemical identification of activated neurones revealed significant number of activated cells to be oxytocin positive, whereas only few vasopressin, tyrosine hydroxylase (TH) or corticotrophin-releasing factor (CRF) neurones were double-labelled. Injection of the retrograde tracer fluorogold into the NTS resulted in labelling of significant numbers of parvocellular oxytocin, but not vasopressin, TH or CRF, PVN neurones. We conclude that centrally administered NPFF stimulates brainstem-projecting oxytocin PVN neurones. Oxytocin released from terminals within the NTS oxytocin thus modulate the activity of ascending visceral autonomic pathways that synapse initially within the NTS.
神经肽FF（NPFF）是一种吗啡调节肽，在中枢自主神经和神经内分泌调节中逐渐成为一种重要的神经调节剂。NPFF免疫反应性和受体已在脑和脊髓内离散的自主神经区域中被鉴定出来，包括下丘脑室旁核（PVN）。在本研究中，我们研究了脑室内（i.c.v.）注射NPFF对投射到孤束核（NTS）脑干核的化学鉴定的PVN神经元激活的影响。在清醒大鼠中，10μg剂量的i.c.v. NPFF（而非8μg）可导致动脉血压升高。免疫组织化学分析显示，与接受i.c.v.生理盐水的对照组相比，i.c.v.注射NPFF后，活化（Fos阳性）的PVN神经元呈剂量依赖性增加。活化的PVN神经元主要位于核的小细胞区，大细胞亚区中Fos阳性细胞相对较少。对活化神经元的化学鉴定显示，大量活化细胞为催产素阳性，而只有少数加压素、酪氨酸羟化酶（TH）或促肾上腺皮质激素释放因子（CRF）神经元呈双标记。将逆行示踪剂荧光金注射到NTS中导致大量小细胞催产素PVN神经元被标记，但加压素、TH或CRF神经元未被标记。我们得出结论，中枢给予NPFF可刺激投射到脑干的催产素PVN神经元。因此，从NTS内终末释放的催产素可调节最初在NTS内形成突触的内脏自主神经通路的上行活动。
