Department of Psychology, Tokiwa University, Mito, Ibaraki, Japan; Department of Systems Physiology, University of the Ryukyus, Faculty of Medicine, Nishihara, Okinawa, Japan.
Physiol Behav. 2021 Aug 1;237:113432. doi: 10.1016/j.physbeh.2021.113432. Epub 2021 Apr 23.
Autism spectrum disorder (ASD) is defined by two core behavioral characteristics, namely, restricted repetitive behaviors and impaired social-communicative functioning. BTBR Tltpr3/J (BTBR) mice provide a valuable animal model for ASD to elucidate the underlying mechanisms of these two behavioral characteristics of ASD. This study examined the social function of excessive grooming behavior in BTBR mice as a phenotype of restricted repetitive behaviors. Compared to the control C57BL/6 J (B6) strain, BTBR mice showed increased self-grooming when placed alone in a test apparatus, and this behavior was even more evident when confronted with a stimulus mouse (either B6 or BTBR) in a three-chamber test apparatus. While B6 mice tended to groom their face/snout region on the empty side of the chamber, BTBR mice showed excessive grooming with frequent transitions among grooming body regions on the side of the chamber containing a social stimulus. Acute systemic injection of buspirone,a serotonin 1A receptor agonist, as an anxiolytic, facilitated approach behavior toward social stimuli in the three-chamber setting in both B6 and BTBR mice. However, this treatment did not affect grooming behavior in B6 mice and significantly enhanced self-grooming in BTBR mice. These behaviors in BTBR mice suggest a potential signaling function of grooming in response to social stimuli, in which bodywide grooming of BTBR mice expressed in the proximity of social opponents may stimulate the release of olfactory (possibly dismissive) signals. Consequently, the putative neural mechanisms underlying excessive grooming may differ from those regulating social approaches that are associated with anxiolytic mechanisms.
自闭症谱系障碍（ASD）的两个核心行为特征为受限的重复行为和受损的社交沟通功能。BTBR Tltpr3/J（BTBR）小鼠为 ASD 提供了一个有价值的动物模型，以阐明 ASD 这两个行为特征的潜在机制。本研究检查了 BTBR 小鼠过度梳理行为的社交功能，作为受限重复行为的表型。与对照 C57BL/6J（B6）品系相比，BTBR 小鼠在单独放置于测试设备中时表现出更多的自我梳理行为，而在三箱测试设备中面对刺激小鼠（B6 或 BTBR）时，这种行为更为明显。虽然 B6 小鼠倾向于在腔室的空侧梳理面部/鼻子区域，但 BTBR 小鼠在包含社交刺激的腔室一侧频繁转换梳理身体区域，表现出过度梳理。急性全身注射丁螺环酮，一种 5-羟色胺 1A 受体激动剂，作为抗焦虑药，促进了 B6 和 BTBR 小鼠在三箱设置中对社交刺激的接近行为。然而，这种治疗方法并未影响 B6 小鼠的梳理行为，却显著增强了 BTBR 小鼠的自我梳理行为。BTBR 小鼠的这些行为表明，梳理行为可能对社交刺激具有潜在的信号功能，BTBR 小鼠在社交对手附近表现出的全身梳理行为可能会刺激嗅觉（可能是轻蔑）信号的释放。因此，过度梳理的潜在神经机制可能与与抗焦虑机制相关的社交接近的调节机制不同。
