Shair H N, Masmela J R, Hofer M A
Department of Psychiatry, Columbia College of Physicians and Surgeons, Columbia University, New York State Psychiatric Institute, New York 10032, USA.
Physiol Behav. 1999;65(4-5):769-72. doi: 10.1016/s0031-9384(98)00218-2.
Twelve-day-old isolated rat pups reduce their rates of ultrasonic vocalization (USV) when an anesthetized adult is placed into the test cage, whether the adult is their dam or an unfamiliar male. USV rates remain very low even after removal of the male (inhibition). However, after removal of the dam, pups greatly increase their rates of USV over their first isolation period (potentiation). USV potentiation can be induced by either an awake, normally behaving dam or by one that is anesthetized. To test the role of olfaction in inhibition and potentiation, PND12 pups were rendered anosmic via intranasal infusion of 5% zinc sulphate (ZnSO4). Control pups were infused with normal saline. After overnight separation from the dam, the USV and other behaviors of pups were recorded during a 6-min test. Each pup was tested during an initial isolation period and a final isolation period. In the first experiment, an anesthetized adult (dam or unfamiliar male) or no companion was placed in contact with the pup during the middle minute. Anosmia prevented both potentiation and inhibition of USV by passive adult contact. Thus, it seems likely that pups use olfactory discrimination as the basis for these two highly differentiated vocal responses to social stimuli. Results from two additional experiments demonstrate that anosmia does not prevent potentiation when the adult dam is active and interacting with the pup on either postnatal day 12 or 8.
当将一只麻醉的成年大鼠放入测试笼时，12日龄的隔离大鼠幼崽会降低其超声波发声（USV）的频率，无论该成年大鼠是它们的母鼠还是陌生雄鼠。即使在移除雄鼠后（抑制作用），USV频率仍保持在很低的水平。然而，在移除母鼠后，幼崽在其首次隔离期间USV频率大幅增加（增强作用）。清醒、行为正常的母鼠或麻醉的母鼠均可诱导USV增强。为了测试嗅觉在抑制和增强作用中的作用，通过鼻内注入5%硫酸锌（ZnSO4）使出生后第12天（PND12）的幼崽嗅觉缺失。对照幼崽注入生理盐水。在与母鼠过夜分离后，在6分钟的测试期间记录幼崽的USV及其他行为。每只幼崽在初始隔离期和最终隔离期都进行了测试。在第一个实验中，在中间一分钟将一只麻醉的成年大鼠（母鼠或陌生雄鼠）或不放置同伴与幼崽接触。嗅觉缺失可防止被动成年接触对USV的增强和抑制作用。因此，幼崽似乎很可能将嗅觉辨别作为对社会刺激这两种高度分化的发声反应的基础。另外两个实验的结果表明，当成年母鼠在出生后第12天或第8天活跃并与幼崽互动时，嗅觉缺失不会阻止增强作用。
