Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada.
Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada; Department of Psychology, Brock University, St. Catharines, Ontario, Canada.
Pharmacol Biochem Behav. 2019 Jun;181:77-85. doi: 10.1016/j.pbb.2019.04.009. Epub 2019 Apr 26.
Rats can emit 22-kHz or 50-kHz ultrasonic vocalizations (USVs) in negative, as well as positive contexts which index their emotional state. 22-kHz USVs are emitted during aversive contexts and can be initiated by activation of the ascending cholinergic pathways originating from the laterodorsal tegmental nucleus or initiated pharmacologically by injection of cholinergic agonists into target areas of these pathways (medial cholinoceptive vocalization strip). Conversely, 50-kHz USVs are emitted during positive pro-social contexts and can be initiated by stimulation of ascending dopaminergic pathways originating from the ventral tegmental area or by injection of dopamine agonists into target areas of these pathways (nucleus accumbens shell). Recently, we have shown an inhibitory effect a positive emotional state has on the emission of carbachol-induced 22-kHz USVs from the anterior hypothalamic/medial preoptic area. However, this structure is a fragment of that cholinoceptive vocalization strip. We wanted to examine if we could observe similar effect when the aversive state is induced from the lateral septum, the most rostral division of the cholinoceptive vocalization strip. The results supported previous findings. First, microinjection of the dopamine agonist R-(-)-apomorphine into the nucleus accumbens shell resulted in increased emission of frequency modulated (FM) 50-kHz USVs that are regarded as signals expressing a positive emotional state in rats. Second, FM 50-kHz USVs and not flat (F) 50-kHz USVs were able to decrease 22-kHz USVs induced by microinjections of carbachol into the lateral septum. This research provides further support to the hypothesis that the initiation of a positive emotional state functionally antagonizes initiation of a negative emotional state in rats.
老鼠可以在负面和正面的情况下发出 22kHz 或 50kHz 的超声波（USV），这些声音可以反映它们的情绪状态。22kHz 的 USV 是在令人厌恶的情况下发出的，可以通过激活起源于外侧背侧被盖核的上行胆碱能通路来引发，也可以通过向这些通路的靶区注射胆碱能激动剂来引发（内侧胆碱能发声带）。相反，50kHz 的 USV 是在积极的亲社会环境中发出的，可以通过刺激起源于腹侧被盖区的上行多巴胺能通路来引发，也可以通过向这些通路的靶区注射多巴胺激动剂来引发（伏隔核壳）。最近，我们已经证明，积极的情绪状态会抑制由下丘脑前内侧/视前区注射 carbachol 引起的 22kHz USV 的产生。然而，这个结构是胆碱能发声带的一个片段。我们想检查一下，如果我们能从胆碱能发声带最前部的外侧隔区诱导出厌恶状态，是否能观察到类似的效果。结果支持了先前的发现。首先，将多巴胺激动剂 R-(-)-apomorphine 微注射到伏隔核壳中，导致频率调制（FM）50kHz USV 的发射增加，这种 USV 被认为是大鼠表达积极情绪的信号。其次，FM 50kHz USV 而不是平坦（F）50kHz USV 能够减少由 carbachol 微注射到外侧隔区引起的 22kHz USV。这项研究进一步支持了这样的假设，即积极情绪状态的启动在功能上拮抗了大鼠消极情绪状态的启动。
