Peele P, Salazar I, Mimmack M, Keverne E B, Brennan P A
Sub-Department of Animal Behaviour, University of Cambridge, High Street, Madingley, Cambridge, CB3 8AA, UK.
Eur J Neurosci. 2003 Aug;18(3):622-8. doi: 10.1046/j.1460-9568.2003.02790.x.
Mouse urine contains a complex mixture of chemosignals including a variety of small volatile molecules that are bound to major urinary proteins. In addition to signalling maleness, male urine also conveys information about individuality, which allows recently mated female mice to distinguish the urinary chemosignals of the mating male from those of an unfamiliar male. The highly polymorphic nature of the major urinary proteins makes them a likely candidate for conveying individuality information in the context of the pregnancy block effect. This was investigated by comparing the pregnancy-blocking effectiveness of a high molecular weight urinary fraction, containing major urinary proteins, with that of a low molecular weight fraction containing volatile ligands. Not only was the high molecular weight fraction ineffective in blocking pregnancy, but it also appeared to be less important in signalling individuality than the low molecular fraction. The high molecular weight fraction was ineffective in inducing expression of the immediate early gene product egr-1 in the accessory olfactory bulb. In contrast, the low molecular weight fraction induced egr-1 expression in the mitral/tufted neurons in the anterior subregion of the accessory olfactory bulb, suggesting that they activate the V1R class of vomeronasal receptor neuron.
小鼠尿液中含有多种化学信号的复杂混合物，包括与主要尿蛋白结合的各种小分子挥发性物质。除了表明雄性特征外，雄性小鼠尿液还传达有关个体性的信息，这使得刚交配过的雌性小鼠能够区分交配雄性的尿液化学信号与陌生雄性的尿液化学信号。主要尿蛋白的高度多态性使其有可能在妊娠阻断效应的背景下传递个体性信息。通过比较含有主要尿蛋白的高分子量尿部分与含有挥发性配体的低分子量部分对妊娠的阻断效果来对此进行研究。高分子量部分不仅在阻断妊娠方面无效，而且在传递个体性信号方面似乎也不如低分子量部分重要。高分子量部分在诱导副嗅球中即早基因产物egr-1的表达方面无效。相比之下，低分子量部分在副嗅球前部区域的二尖瓣/簇状神经元中诱导了egr-1的表达，这表明它们激活了犁鼻器受体神经元的V1R类。
