T-Maze Performance after Developmental Exposure to ¹⁹F Tagged 5-HTP in Chicks

Abstract

Chicks were used as a model to investigate behavioral effects of administering a new compound intended for use with magnetic resonance. The compound has multiple 19F atom tags covalently bonded to the indole ring of 5-hydroxytryptophan (PF-5HTP), the immediate precursor to the neurotransmitter serotonin. On incubation Day 17, 5 microg of PF-5-HTP, an equivalent amount of 5-HTP, or just 200 microL of the weak phosphate buffered saline (PBS) vehicle was injected into the airsac of each egg. Three days after hatching, chicks were isolated at the top of a simple T-Maze which, when traversed correctly, enabled them to return to their brood mates. A second trial in the T-Maze was conducted about three hours later. The brief period of isolation at the start of a trial causes social distress in chicks who are reinforced by returning to the brood. The task was selected as being sensitive to functioning of the serotonin pathways whose development might be altered by administering the compound during brain development. Repeated-measures analysis of variance yielded a statistically significant main effect for trial within groups, but no significant difference between injection groups. Administering a low dose of the fluorine tagged compound during development did not impair performance on this T-maze task.

Serotonin a la carte: Supplementation with the serotonin precursor 5-hydroxytryptophan

“…Dingman et al (2004a) created this new compound as a probe for investigating neural development in chicks. Importantly, the authors found that administration of the fluorine tagged 5-HTP during development did not impair performance on a Tmaze behavioral task (Dingman et al, 2004b).…”

Fluorine-Tagged 5-Hydroxytryptophan to Investigate Amino Acid Metabolism In Vivo

“…In that study, administering PF-5-HTP mimicked the animal behaviour effect after administration of the untagged version of 5-HTP. Toxicity has not been observed in animal models [15, 16]. Nor was toxicity observed in L. esculenta in this study, which demonstrates that plants can serve as useful in vivo models for investigating the biosynthesis of tryptophan metabolites, which are shared by plants and animals.…”