Role of neurotransmitters 5-hydroxytryptamine and substance P in anorexia induction following oral exposure to the trichothecene T-2 toxin.

Trichothecene mycotoxins, a family of common contaminants on cereal grains, are known to negatively impact human and animal health with adverse effect on food consumption being of particular concern. T-2 toxin has been previously demonstrated to induce anorectic response in several animal species including mouse, rat, rabbit. Although the T-2 toxin-induced anorectic response has been associated with the release of gut satiety hormone, much less is known about the role of neurotransmitter in this response. To address this gap, we employed a nocturnal mouse food refusal model to test the hypothesis that neurotransmitters 5-hydroxytryptamine (5-HT) and substance P (SP) mediate anorexia induction by T-2 toxin. Elevations of plasma 5-HT and SP markedly corresponded to anorexia induction following oral exposure to T-2 toxin. Direct administration of exogenous 5-HT and SP induced anorectic responses similar to T-2 toxin. The 5-HT3 receptor (5-HT3R) antagonist granisetron evoked a dose-dependent attenuation of both 5-HT- and T-2 toxin-induced anorectic responses. Pretreatment with neurokinin-1 receptor (NK-1R) antagonist Emend dose-dependently attenuated both SP- and T-2 toxin-induced anorectic responses. To summarize, the results suggest that both 5-HT and SP play important roles in anorexia induction by T-2 toxin. 5-HT is more potent and long-acting than SP in this response.