Meeting Abstract

P2.43  Wednesday, Jan. 5  Potential sites for arginine vasotocin modulation of sensory systems differ with phase in a sex changing teleost (Thalassoma duperrey). GROOM, K/LB; TRICAS, T*; University of Hawaii at Manoa; University of Hawaii at Manoa kasielb@hawaii.edu

The neuropeptide arginine vasotocin (AVT) and its mammalian homologue, arginine vasopressin, modulate aggression, territoriality, mating, social behaviors, and sensory systems in vertebrates. In fish, AVT neurons project to important sensory processing regions in the brain. The protogynous and sequentially hermaphroditic saddleback wrasse, Thalassoma duperrey, provides an excellent model in which to study the effects of neuropeptides on behavior and sensory systems during sex change. T. duperrey use visual, olfactory, and auditory signals during reproduction and exhibit rapid changes in behaviors associated with sex change that occur independently of gonadal condition and steroid levels. Although visual and olfactory cues promote and inhibit sex change in females, the corresponding changes in central processing circuits are unknown. Hormone neuromodulators may play a key role in behavioral and physiological changes that occur during sex change. The density of varicosities, or potential AVT release sites, within a region of the brain is an indicator of the relative amount of AVT that may be released within that region. This study defines the differences in the number of AVT-ir varicosities in sensory regions of the brain of each sexual phase of the saddleback wrasse. Differences among sexes that are present in specific regions may indicate potential differences in AVT modulation of sensory systems and behavior as sex change occurs. Definition of the relationship of development, function, and modulation of AVT to behavior and sensory functions may have important implications in the field of ethology and also provide key insight into the development of therapies for human behavioral disorders, such as autism.