Key S, Wray S
Cellular and Developmental Neurobiology Section, National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, MD 20892-4156, USA.
J Neuroendocrinol. 2000 Jun;12(6):535-45. doi: 10.1046/j.1365-2826.2000.00486.x.
In adult rodents, the peptide galanin is expressed in a subpopulation of hypothalamic luteinizing hormone-releasing hormone (LHRH) neurones in an activity-dependent manner. In this investigation, we examined whether galanin mRNA expression in mice was activated coincident with LHRH mRNA expression, as LHRH neurones differentiate from the olfactory placode. Using in situ hybridization, we show (i) that galanin mRNA is coexpressed in LHRH neurones prenatally, (ii) that there is a decrease in galanin mRNA expression relative to LHRH mRNA expression once LHRH mRNA positive/galanin mRNA positive neurones migrate out of the olfactory pit and into the nasal septum, and (iii) the presence of a novel population of galanin mRNA positive/LHRH mRNA negative expressing neurones in the olfactory pit/vomeronasal organ which do not migrate into the central nervous systenm (CNS). This study demonstrates that there are at least two populations of galanin mRNA expressing neurones arising from the olfactory placode; one that remains in nasal regions, is LHRH mRNA negative and whose function is unknown, and one which is coexpressed with LHRH. In addition, the temporal expression of galanin mRNA in LHRH cells indicates that initial activation and subsequent inactivation of galanin mRNA expression is independent of synaptic CNS connections.
在成年啮齿动物中，甘丙肽在促黄体生成素释放激素（LHRH）神经元的下丘脑亚群中以活动依赖的方式表达。在本研究中，我们研究了随着LHRH神经元从嗅基板分化，小鼠中甘丙肽mRNA表达是否与LHRH mRNA表达同时被激活。通过原位杂交，我们发现：（i）甘丙肽mRNA在产前与LHRH神经元共表达；（ii）一旦LHRH mRNA阳性/甘丙肽mRNA阳性神经元从嗅凹迁移到鼻中隔，相对于LHRH mRNA表达，甘丙肽mRNA表达会下降；（iii）在嗅凹/犁鼻器中存在一群新的甘丙肽mRNA阳性/LHRH mRNA阴性表达神经元，它们不会迁移到中枢神经系统（CNS）。这项研究表明，至少有两群来自嗅基板的甘丙肽mRNA表达神经元；一群留在鼻区，LHRH mRNA阴性，其功能未知，另一群与LHRH共表达。此外，LHRH细胞中甘丙肽mRNA的时间表达表明，甘丙肽mRNA表达的初始激活和随后的失活与中枢神经系统的突触连接无关。
