Distribution and changes of serotonin and dopamine levels in the central nervous system and ovary of the Pacific white shrimp, Litopenaeus vannamei, during ovarian maturation cycle

Abstract

We investigated changes in serotonin (5-HT) and dopamine (DA) levels and in their distribution patterns in the central nervous system (CNS) and ovary during the ovarian maturation cycle in the Pacific white shrimp, Litopenaeus vannamei. The concentrations of these two neurotransmitters were determined by using high performance liquid chromatography with electrochemical detection. The 5-HT concentration exhibited a gradual increase in the brain and thoracic ganglia during early ovarian stages I, II, and III, reaching a maximum at the mature ovarian stage IV, whereas DA showed its highest concentration at ovarian stage II in the brain and thoracic ganglia and then declined to its lowest concentration at ovarian stage IV. In the ovaries, 5-HT was lowest at ovarian stage I and gradually increased to a peak at ovarian stage IV. Conversely, the concentration of DA was highest at ovarian stages I and II and lowest at ovarian stage IV. In the brain, 5-HT immunoreactivity (-ir) from stage IV and DA-ir from stage II were distributed extensively in neurons of clusters 6, 11, and 17, in fibers, and in the anterior and posterior medial protocerebral, olfactory, antenna II, and tegumentary neuropils. In the circumesophageal, subesophageal, thoracic, and abdominal ganglia, both 5-HT-ir and DA-ir were detected in neuropils and surrounding neurons and fibers. 5-HT-ir and DA-ir were more intense in the thoracic ganglia than in other parts of the CNS. In the ovary, 5-HT-ir exhibited high intensity in late oocytes, whereas DA-ir was more intense in early oocytes. Thus, opposing changes occur in the levels of these two neurotransmitters and in their specific localizations in the CNS and ovary during ovarian maturation, indicating their important involvement in female reproduction.

Dynamics of Vitellogenin and Vitellogenesis-Inhibiting Hormone Levels in Adult and Subadult Whiteleg Shrimp, Litopenaeus vannamei: Relation to Molting and Eyestalk Ablation1

“…5-HT and dopamine levels changed in relation to ovarian maturation in L. vannamei, and 5-HT levels increased in the brain, thoracic ganglia, and ovary with advancing maturity [12]. These previous reports suggest that 5-HT levels were synchronized with VG levels in L. vannamei.…”

“…Embedded ovaries were sectioned to a thickness of 5 µm, stained with hematoxylin (for 2 min, Mayer hematoxylin solution, Wako) and eosin (for 6 min, 1% eosin Y, Sigma-Aldrich) through hydration and dehydration with an ethanol and xylene series, and observed under a light microscope. Oocyte developmental stage was determined according to previous reports [3,12].…”

“…The whiteleg shrimp, Litopenaeus vannamei, is at present, one of the most significant species targeted in commercial aquaculture, and is also often employed in reproductive studies [3,[8][9][10][11][12]. We have previously isolated six type I CHH family peptides that can significantly inhibit the transcription of VG mRNA from the sinus gland of L. vannamei, with Liv-SGP-G (L. vannamei sinus gland peptide-G) being the predominant species present [11].…”

Distribution of serotonin and dopamine in the central nervous system of the female mud crab, Scylla olivacea (Herbst)

“…We also observed that the location of 5-HT-ir neurons was different from DA. In M. rosenbergii and L. vannamei, 5-HT and DA existed in different sets of neurons throughout the CNS, and it is postulated that these two neurotransmitters may be released to act as antagonists (Vázquez-Acevedo et al, 2009;Tinikul et al, 2009aTinikul et al, , 2011.…”

Inducing synchronous ovarian maturation in the crayfish,Procambarus clarkii, via eyestalk interventional injection as compared with eyestalk ablation and combined injection of serotonin and domperidone

“…In M. rosenbergii and L. vannamei, the changes in DA and 5-HT levels in the central nervous system (CNS) and ovary during the ovarian cycle (Tinikul et al 2008;Tinikul, Poljaroen, Kornthong, Chotwiwatthanakun, Anuracpreeda, Poomtong, Hanna & Sobhon 2011), and the changes in haemolymph Vg concentrations caused by 5-HT injection (Tinikul et al 2008) or DA injection (Chen et al 2003) supported the judgment that 5-HT stimulates ovarian development (Kulkarni, Nagabhushanam, Amaldoss, Jaiswal & Fingerman 1991b, 1992Meeratana, Withyachumnarnkul, Damrongphol, Wongprasert, Suseangtham & Sobhon 2006), while DA inhibits it (Sarojini, Nagabhushanam & Fingerman 1996;Sarojini, Nagabhushanam, Devi & Fingerman 1995a). In M. rosenbergii and L. vannamei, the changes in DA and 5-HT levels in the central nervous system (CNS) and ovary during the ovarian cycle (Tinikul et al 2008;Tinikul, Poljaroen, Kornthong, Chotwiwatthanakun, Anuracpreeda, Poomtong, Hanna & Sobhon 2011), and the changes in haemolymph Vg concentrations caused by 5-HT injection (Tinikul et al 2008) or DA injection (Chen et al 2003) supported the judgment that 5-HT stimulates ovarian development (Kulkarni, Nagabhushanam, Amaldoss, Jaiswal & Fingerman 1991b, 1992Meeratana, Withyachumnarnkul, Damrongphol, Wongprasert, Suseangtham & Sobhon 2006), while DA inhibits it (Sarojini, Nagabhushanam & Fingerman 1996;Sarojini, Nagabhushanam, Devi & Fingerman 1995a).…”