Modney B K, Yang Q Z, Hatton G I
Department of Psychology, Michigan State University, East Lansing 48824-1117.
Brain Res. 1990 Apr 16;513(2):270-3. doi: 10.1016/0006-8993(90)90466-o.
Electrical stimulation of the lateral olfactory tract (LOT) has been shown to excite, monosynaptically, supraoptic nucleus (SON) neurons in slices of hypothalamus taken from male, virgin female or lactating rats. Only in the last of these, however, did 10 min of 10 Hz stimulation produce an increase in the incidence of Lucifer yellow dye-coupling, an indicator of electrotonic interactions. This coupling is virtually exclusively dendrodendritic. Since virgin females that have been induced to show full maternal behavior have altered dendritic morphology reminiscent of lactating animals (but different from males and untreated virgins) we investigated the effects of LOT stimulation in slices from maternally behaving virgins. Similar to the data for lactating rats, electrical stimulation of this tract, the terminals of which release excitatory amino acid transmitter, increased the incidence of dye-coupling by 112% (P less than 0.01). Also similar to lactating rats, the coupling was dendrodendritic and the increase was due entirely to increasing the number of neurons coupled to the injected neuron. No increase in coupling was seen in stimulated slices from pup-exposed control rats. We conclude that the maternal behaviors engaged in by both real mothers and induced virgins 'primes' the supraoptic neurons to increase coupling in response to olfactory system stimulation. This priming may occur via olfactory and vomeronasal stimulation during such behaviors as sniffing and anogenital licking of the pups. That coupling increased in tissue from maternally behaving virgins comparably to that from nursing mothers further suggests that SON neurons may play a role in maternal behavior independent of its well-documented role in the milk ejection reflex.
对雄性、未生育雌性或哺乳期大鼠下丘脑切片中的视上核（SON）神经元进行电刺激，结果表明电刺激外侧嗅束（LOT）可产生单突触兴奋。然而，仅在最后一组（哺乳期大鼠）中，10分钟的10赫兹刺激使荧光黄染料偶联发生率增加，荧光黄染料偶联是电紧张相互作用的一个指标。这种偶联几乎完全是树突 - 树突型的。由于诱导表现出完全母性行为的未生育雌性具有类似于哺乳期动物（但不同于雄性和未处理的未生育雌性）的改变的树突形态，我们研究了对表现出母性行为的未生育雌性的切片进行LOT刺激的效果。与哺乳期大鼠的数据相似，对该束进行电刺激（其终末释放兴奋性氨基酸递质）使染料偶联发生率增加了112%（P小于0.01）。同样与哺乳期大鼠相似，偶联是树突 - 树突型的，且增加完全是由于与注射神经元偶联的神经元数量增加。在暴露于幼崽的对照大鼠的受刺激切片中未观察到偶联增加。我们得出结论，真正的母亲和诱导的未生育雌性所表现出的母性行为会“启动”视上核神经元，使其在受到嗅觉系统刺激时增加偶联。这种启动可能通过诸如嗅闻和舔舐幼崽肛门生殖器等行为过程中的嗅觉和犁鼻器刺激发生。表现出母性行为的未生育雌性组织中的偶联增加程度与哺乳母亲的组织相当，这进一步表明视上核神经元可能在母性行为中发挥作用，而独立于其在射乳反射中已得到充分证明的作用。
