Bimodal serotonin synthesis in the diurnal rodent, Arvicanthis ansorgei.
FASEB J
; 36(4): e22255, 2022 04.
Article
em En
| MEDLINE
| ID: mdl-35294080
ABSTRACT
In mammals, behavioral activity is regulated both by the circadian system, orchestrated by the suprachiasmatic nucleus (SCN), and by arousal structures, including the serotonergic system. While the SCN is active at the same astronomical time in diurnal and nocturnal species, little data are available concerning the serotonergic (5HT) system in diurnal mammals. In this study, we investigated the functioning of the 5HT system, which is involved both in regulating the sleep/wake cycle and in synchronizing the SCN, in a diurnal rodent, Arvicanthis ansorgei. Using in situ hybridization, we characterized the anatomical extension of the raphe nuclei and we investigated 24 h mRNA levels of the serotonin rate-limiting enzyme, tryptophan hydroxylase 2 (tph2). Under both 12 h12 h light/dark (LD) and constant darkness (DD) conditions, tph2 mRNA expression varies significantly over 24 h, displaying a bimodal profile with higher values around the (projected) light transitions. Furthermore, we considered several SCN outputs, namely melatonin, corticosterone, and locomotor activity. In both LD and DD, melatonin profiles display peak levels during the biological night. Corticosterone plasma levels show a bimodal rhythmic profile in both conditions, with higher levels preceding the two peaks of Arvicanthis locomotor activity, occurring at dawn and dusk. These data demonstrate that serotonin synthesis in Arvicanthis is rhythmic and reflects its bimodal behavioral phenotype, but differs from what has been previously described in nocturnal species.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Serotonina
/
Melatonina
Limite:
Animals
Idioma:
En
Revista:
FASEB J
Assunto da revista:
BIOLOGIA
/
FISIOLOGIA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
França