Center for Basic Medical Research, International University of Health and Welfare, Otawara 324-8501, Japan.
Laboratory of Veterinary Anatomy, Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
Behav Brain Res. 2021 May 7;405:113211. doi: 10.1016/j.bbr.2021.113211. Epub 2021 Feb 27.
Tactile stimulation such as rhythmic stroking elicits 50-kHz ultrasonic vocalizations (USVs) in rats that are thought to reflect positive affective states. Dopaminergic neurotransmission in the nucleus accumbens (NAc) is required for tactile reward-induced 50-kHz USVs; however, it is still unknown whether the accumbal dopaminergic system differentially modulates 50-kHz USV call subtypes induced by rhythmic stroking. We therefore examined both total and categorized 50-kHz USV rate, peak frequency, and duration under dopamine (DA) receptor antagonism in the NAc shell. Bilateral injection of the D1 receptor antagonist SCH 23390 (500 ng/side) plus the D2/D3 receptor antagonist raclopride (25 μg/side) significantly reduced the number of predominantly flat calls with harmonics during stimulation and the number of frequency-modulated (FM) calls after stimulation. In contrast, there were no substantial changes in total and categorized 50-kHz USVs mean peak frequencies and call durations. Therefore, emission of different subtypes of 50-kHz USVs may be differently regulated by dopaminergic transmission. The 50-kHz harmonics and FM USVs induced by rhythmic stroking may be useful behavioral markers for tactile reward in rats.
触觉刺激，如有节奏的轻抚，会引起大鼠产生 50kHz 超声波发声（USVs），这些发声被认为反映了积极的情感状态。伏隔核（NAc）中的多巴胺能神经传递对于触觉奖励诱导的 50kHz USVs 是必需的；然而，目前尚不清楚伏隔核中的多巴胺系统是否会有差异地调节由有节奏的轻抚引起的 50kHz USV 叫声的亚型。因此，我们在 NAc 壳中检查了多巴胺（DA）受体拮抗剂下的总 50kHz USV 率、峰值频率和持续时间以及分类。双侧注射 D1 受体拮抗剂 SCH 23390（500ng/侧）加 D2/D3 受体拮抗剂氯丙嗪（25μg/侧）可显著减少刺激期间主要具有谐波的扁平叫声的数量和刺激后频率调制（FM）叫声的数量。相比之下，总 50kHz USVs 和分类 50kHz USVs 的平均峰值频率和叫声持续时间没有实质性变化。因此，不同类型的 50kHz USVs 的发射可能由多巴胺传递以不同的方式调节。由有节奏的轻抚引起的 50kHz 谐波和 FM USVs 可能是大鼠触觉奖励的有用行为标志物。
