School of Biology, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand.
Folia Histochem Cytobiol. 2022;60(1):1-12. doi: 10.5603/FHC.a2022.0008. Epub 2022 Feb 17.
Dopamine (DA) is a neurotransmitter/neuromodulator found in both central and peripheral nervous systems. It plays several physiological functions in some mammalian and avian species. DA has been indicated to be associated with the neuroendocrine regulation of the reproductive cycle and maternal behaviors in the female native Thai chickens. Indeed, male birds express parental behaviors as well. To date, there are no data describing the functional aspects of the DAergic system in the male native Thai chickens. Thus, the objective of this study was to elucidate the localization of tyrosine hydroxylase (TH; a DA marker) neuronal groups in the brain of the roosters.
The distributions of TH immunoreactivity in the brain were detected utilizing the immunohistochemical technique.
TH immunoreactivity was located throughout the brain and extensively in the diencephalon and mesencephalon. The highest density of TH-immunoreactive (-ir) neurons and fibers was found within the nucleus intramedialis (nI) and nucleus mamillaris lateralis (ML). The numbers of TH-ir neurons within the nucleus anterior medialis hypothalami (AM), nucleus paraventricularis magnocellularis (PVN), nI, and ML were then compared and revealed that the numbers of TH-ir neurons within the nI and ML were significantly higher than those of the AM and PVN.
These present findings suggest that the DAergic neurons within the nI and ML might play an important role in the reproductive activities of the native Thai roosters. Interestingly, the DAergic system in the nI might be involved in male reproductive activities and/or parental behaviors in this equatorial species.
多巴胺（DA）是一种在中枢和外周神经系统中都存在的神经递质/神经调质。它在一些哺乳动物和鸟类物种中发挥着多种生理功能。DA 已被证明与雌性泰国本地鸡生殖周期和母性行为的神经内分泌调节有关。事实上，雄性鸟类也表现出亲代行为。迄今为止，尚无数据描述雄性泰国本地鸡中 DA 能系统的功能方面。因此，本研究的目的是阐明公鸡大脑中天冬氨酸羟化酶（TH；DA 标志物）神经元群的定位。
利用免疫组织化学技术检测大脑中 TH 免疫反应性神经元的分布。
TH 免疫反应性存在于整个大脑中，并且在间脑和中脑中广泛存在。TH 免疫反应性（ir）神经元和纤维的密度最高位于中脑内侧核（nI）和外侧乳头体核（ML）内。然后比较了下丘脑前内侧核（AM）、大细胞室旁核（PVN）、nI 和 ML 内 TH-ir 神经元的数量，并发现 nI 和 ML 内 TH-ir 神经元的数量明显高于 AM 和 PVN。
这些发现表明，nI 和 ML 中的 DA 能神经元可能在泰国本地公鸡的生殖活动中发挥重要作用。有趣的是，nI 中的 DA 能系统可能参与了这种赤道物种的雄性生殖活动和/或亲代行为。
