Female reproductive state is associated with changes in distinct arginine vasotocin cell types in the preoptic area of Astatotilapia burtoni

• Published in: Journal of comparative neurology (1911) Vol. 529; no. 5; pp. 987 - 1003
• Main Authors: Butler, Julie M., Anselmo, Chase M., Maruska, Karen P.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2021; Wiley Subscription Services, Inc
• Subjects: Animals; Arginine; Astatotilapia burtoni; AVT; Cell Count; Cell size; Cichlids - anatomy & histology; Cichlids - physiology; Courtship; Female; Females; Hybridization; Hypothalamus; Hypothalamus - cytology; Immunohistochemistry; Males; mRNA; nonapeptides; Ovulation - physiology; Preoptic area; Preoptic Area - cytology; Preoptic Area - physiology; reproduction; Reproduction - physiology; Reproductive status; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger - biosynthesis; RRID: AB 143165; RRID: AB_2313606; RRID: AB_2336382; RRID: AB_2336827; RRID: AB_514497; RRID: SCR_003070; RRID: SCR_003210; RRID: SCR_014199; RRID: SCR_014329; RRID:AB_2847958; Social behavior; teleost; Vasotocin; Vasotocin - analysis; RRID: AB_514497; RRID: SCR_014199; RRID: SCR_003070; social behavior; teleost; RRID: SCR_003210; RRID: AB_2336382; nonapeptides; RRID:AB_2847958; RRID: AB_2313606; RRID: SCR_014329; RRID: AB 143165; AVT; RRID: AB_2336827; reproduction
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.24995

Nonapeptides play a crucial role in mediating reproduction, aggression, and parental care across taxa. In fishes, arginine vasotocin (AVT) expression is related to social and/or reproductive status in most male fishes studied to date, and is linked to territorial defense, paternal care, and courtship. Despite a plethora of studies examining AVT in male fishes, relatively little is known about how AVT expression varies with female reproductive state or its role in female social behaviors. We used multiple methods for examining the AVT system in female African cichlid fish Astatotilapia burtoni, including immunohistochemistry for AVT, in situ hybridization for avt‐mRNA, and quantitative PCR. Ovulated and mouthbrooding females had similar numbers of parvocellular, magnocellular, and gigantocellular AVT cells in the preoptic area. However, ovulated females had larger magnocellular and gigantocellular cells compared to mouthbrooding females, and gigantocellular AVT cell size correlated with the number of days brooding, such that late‐stage brooding females had larger AVT cells than mid‐stage brooding females. In addition, we found that ventral hypothalamic cells were more prominent in females compared to males, and were larger in mouthbrooding compared to ovulated females, suggesting a role in maternal care. Together, these data indicate that AVT neurons change across the reproductive cycle in female fishes, similar to that seen in males. These data on females complement studies in male A. burtoni, providing a comprehensive picture of the regulation and potential function of different AVT cell types in reproduction and social behaviors in both sexes. We used multiple methods for examining the arginine vasotocin (AVT) system in female African cichlid fish Astatotilapia burtoni. AVT‐ir cell size varied with female reproductive state in a cell type‐dependent manner. Ovulated females had larger magnocellular and gigantocelluar cells than brooding females, and gigantocellular AVT‐ir cell size correlated with the number of days brooding. Overall, our data indicate that AVT neurons change across the reproductive cycle in female fishes, similar to that seen in males.