Central administration of dipeptides, beta-alanyl-BCAAs, induces hyperactivity in chicks

Area of Science:

• Neuroscience
• Endocrinology
• Animal Behavior

Background:

• Carnosine (beta-alanyl-L-histidine) is a potential neurotransmitter involved in neuron-glia interactions.
• Previous research indicated carnosine induces hyperactivity in chicks via intracerebroventricular (i.c.v.) administration.
• This study investigates novel functions of other beta-alanyl dipeptides.

Purpose of the Study:

• To explore the behavioral and endocrine effects of various beta-alanyl dipeptides in chicks.
• To determine if beta-alanyl dipeptides, similar to carnosine, can induce hyperactivity.
• To investigate the involvement of the hypothalamus-pituitary-adrenal (HPA) axis in the observed effects.

Main Methods:

• Intracerebroventricular (i.c.v.) injections of different beta-alanyl dipeptides in chicks.
• Behavioral observation to assess hyperactivity.
• Measurement of corticosterone release to evaluate HPA axis activity.

Main Results:

• Beta-alanyl-L-leucine, but not beta-alanyl-glycine, induced hyperactivity, similar to carnosine.
• Both carnosine and beta-alanyl-L-leucine stimulated corticosterone release.
• Beta-alanyl-L-isoleucine and beta-alanyl-L-valine also showed hyperactivity-inducing and corticosterone-releasing effects, with varying potency.

Conclusions:

• Central administration of beta-alanyl-branched chain amino acids stimulates chick activity via the HPA axis.
• Beta-alanyl-L-leucine, beta-alanyl-L-isoleucine, and beta-alanyl-L-valine were named Excitin-1, Excitin-2, and Excitin-3, respectively.
• These findings highlight novel functions of specific dipeptides in neuroendocrine regulation.