Localization of three types of arginine vasotocin receptors in the brain and pituitary of the newt Cynops pyrrhogaster

Abstract

The distribution of three types of arginine vasotocin (AVT) receptors in the brain and pituitary of the newt Cynops pyrrhogaster, namely, the V1a-, V2-, and V3/V1b-type receptors, was studied by means of in situ hybridization and immunohistochemistry. mRNA signals and immunoreactive cells for the V1a-type receptor were observed in the telencephalon (mitral layer of the olfactory bulb, dorsal and medial pallium, lateral and medial amygdala, bed nucleus of the decussation of the fasciculus telencephali, bed nucleus of the stria terminalis), diencephalon (anterior preoptic area, magnocellular preoptic nucleus, suprachiasmatic nucleus, ventral thalamus, dorsal and ventral hypothalamic nucleus), mesencephalon (tegmentum, interpeduncular nucleus), and medulla oblongata (median reticular formation, nucleus motorius tegmenti). Cells expressing the V2-type receptor were found in the telencephalon (medial pallium, lateral and medial amygdala, bed nucleus of the decussation of the fasciculus telencephali), and mesencephalon (tegmentum trigemini and facialis). In the paraphysis (possibly the main site of cerebrospinal fluid production), only V2-type receptor mRNA signal and immunoreactivity were detected. V3/V1b-type receptor mRNA was expressed in the diencephalon (dorsal hypothalamic nucleus, nucleus tuberculi posterioris), mesencephalon (tegmentum, interpeduncular nucleus), and medulla oblongata (raphe nucleus), whereas V3/V1b-type-receptor-like immunoreactivity was scarcely detectable in the entire brain. The V3/V1b-type receptor was predominantly expressed in the anterior pituitary. V3/V1b-type receptor and proopiomelanocortin mRNAs were co-localized in the distal lobe of the pituitary. This is the first report of the distribution of three types of AVT receptor in the brain and pituitary of non-mammalian vertebrates.

Distribution of nonapeptide systems in the forebrain of an African cichlid fish, Astatotilapia burtoni

“…Compared to our understanding of nonapeptide distributions in a variety of taxa, receptor distribution is not widely studied, especially in non-mammalian vertebrates. Distributions of both AVT and IST receptor mRNA have only been described for two species of birds (Leung et al, 2011) and two amphibians (Acharjee et al, 2004;Hasunuma et al, 2010), and, with the exception of the original study by Kline et al (2011) and the present study, there have been no published studies that describe the distributions of these receptors in reptiles or teleosts.…”

Expression patterns of Pax6 and Pax7 in the adult brain of a urodele amphibian, Pleurodeles waltl

“…Specifically in amphibians, it has been described as a posterior telencephalic organ adjacent to the choroid plexus of the third ventricle (Ariëns‐Kappers, 1956), but unlike the plexus it lacks the uptake mechanisms for cerebrospinal fluid (Jansen and Diederen, 1987). In urodeles a type of arginine vasotocin receptor was observed in the paraphysis, related to the osmotic and/or ionic regulation of the cerebrospinal fluid (Hasunuma et al, 2010). Strong Pax7 expression was observed in the paraphysis of adult Pleurodeles , and not in the adjacent choroid plexus, suggesting that it likely constitutes a derivative of the telencephalic roof.…”

AVT is involved in the regulation of ion transport in the intestine of the sea bream (Sparus aurata)

“…Furthermore, the gastrointestinal tract of the sea bream is a target for endocrine regulation of ion transport (Ferlazzo et al, 2012;Fuentes et al, 2010a;Fuentes et al, 2006;Fuentes et al, 2010b). Previous studies in vertebrates have demonstrated the widespread distribution of receptors for AVP/AVT in the intestine of birds (Tan et al, 2000), amphibians (Hasunuma et al, 2010) and mammals (Lolait et al, 1992;Morel et al, 1993). In fish, the intestinal expression of AVT receptor V1a-type and V2-type have been demonstrated in the African lungfish, Protopterus annectens (Konno et al, 2009).…”