Croaking is a unique component of reproductive behaviour in amphibians which plays a key role in intraspecies communication and mate evaluation. While gonadal hormones are known to induce croaking, central regulation of sound production is less studied. Croaking is a dramatic, transient activity that sets apart an animal from non-croaking individuals. Herein, we aim at examining the profile of the neuropeptide cocaine- and amphetamine-regulated transcript (CART) in actively croaking and non-croaking frog Microhyla nilphamariensis. In anurans, this peptide is widely expressed in the areas inclusive of acoustical nuclei as well as areas relevant to reproduction. CART immunoreactivity was far more in the preoptic area (POA), anteroventral tegmentum (AV), ventral hypothalamus (vHy), pineal (P) and pituitary gland of croaking frog compared to non-croaking animals. On similar lines, tissue fragments collected from the mid region of the brain inclusive of POA, vHy, AV, pineal and pituitary gland of croaking frog showed upregulation of CART mRNA. However, CART immunoreactivity in the neuronal perikarya of raphe (Ra) was completely abolished during croaking activity. The data suggest that CART signaling in the brain may be an important player in mediating croaking behaviour in the frog.

鸣叫是两栖动物生殖行为的独特组成部分，在种内交流和配偶评估中发挥着关键作用。虽然已知性腺激素会引起鸣叫，但对发声的中枢调节的研究较少。鸣叫是一种戏剧性的、短暂的活动，它将动物与不鸣叫的个体区分开来。在此，我们的目的是检查活跃鸣叫和非鸣叫青蛙Microhyla nilphamariensis中神经肽可卡因和安非他明调节转录物 (CART) 的概况。在无尾目动物中，这种肽广泛表达于包括听核在内的区域以及与生殖相关的区域。与非鸣叫动物相比，鸣叫蛙的视前区（POA）、前腹侧被盖（AV）、腹侧下丘脑（vHy）、松果体（P）和垂体的CART 免疫反应性要高得多。类似地，从呱呱青蛙大脑中部区域（包括 POA、vHy、AV、松果体和垂体）收集的组织碎片显示 CART mRNA 上调。然而，中缝神经元核周(Ra) 的 CART 免疫反应性在鸣叫活动期间完全消失。数据表明，大脑中的 CART 信号可能在调节青蛙的鸣叫行为中发挥着重要作用。