Melnick Igor, Pronchuk Nina, Cowley Michael A, Grove Kevin L, Colmers William F
Department of Pharmacology, University of Alberta, Edmonton AB, T6G 2H7, Canada.
Neuron. 2007 Dec 20;56(6):1103-15. doi: 10.1016/j.neuron.2007.10.034.
Homeostatic regulation of energy balance in rodents changes dramatically during the first 3 postnatal weeks. Neuropeptide Y (NPY) and melanocortin neurons in the arcuate nucleus, a primary energy homeostatic center in adults, do not fully innervate the paraventricular nucleus (PVN) until the third postnatal week. We have identified two classes of PVN neurons responsive to these neuropeptides, tonically firing neurosecretory (NS) and burst-firing preautonomic (PA) cells. In neonates, NPY could inhibit GABAergic inputs to nearly all NS and PA neurons, while melanocortin regulation was minimal. However, there was a dramatic, age-dependent decrease in NPY responses specifically in the PA neurons, and a 3-fold increase in melanocortin responses in NS cells. These age-dependent changes were accompanied by changes in spontaneous GABAergic currents onto these neurons. This primarily NPYergic regulation in the neonates likely promotes the positive energy balance necessary for growth, while the developmental switch correlates with maturation of homeostatic regulation of energy balance.
啮齿动物出生后前三周内，能量平衡的稳态调节会发生显著变化。弓状核是成体主要的能量稳态中心，其中的神经肽Y（NPY）和黑皮质素神经元直到出生后第三周才完全支配室旁核（PVN）。我们已鉴定出两类对这些神经肽有反应的PVN神经元，即持续放电的神经分泌（NS）细胞和爆发式放电的自主神经前体（PA）细胞。在新生儿中，NPY可抑制几乎所有NS和PA神经元的GABA能输入，而黑皮质素调节作用极小。然而，PA神经元中NPY反应出现显著的年龄依赖性降低，NS细胞中黑皮质素反应增加了3倍。这些年龄依赖性变化伴随着这些神经元上自发GABA能电流的变化。新生儿中这种主要由NPY介导的调节可能促进生长所需的正能量平衡，而这种发育转变与能量平衡稳态调节的成熟相关。
