GABA Supplementation Negatively Affects Cognitive Flexibility Independent of Tyrosine

Abstract

Increasing evidence, particularly from animal studies, suggests that dopamine and GABA are important modulators of cognitive flexibility. In humans, increasing dopamine synthesis through its precursor tyrosine has been shown to result in performance improvements, but few studies have reported the effects of GABA supplementation in healthy participants. We conducted a double-blind, placebo-controlled, randomized experiment to test the interactive effects of tyrosine and GABA administration on two measures of cognitive flexibility, response inhibition and task switching. A total of 48 healthy volunteers were split into four groups (placebo, tyrosine alone, GABA alone, and tyrosine and GABA combined). They completed cognitive flexibility tasks at baseline and after drug administration. We found that tyrosine alone had no impact on the measures of cognitive flexibility, whereas GABA alone and in combination with tyrosine worsened task switching. Our results provide preliminary evidence that putative increases in GABA and dopamine synthesis do not interact to affect cognitive flexibility performance.

Duodenal infusion of soy protein hydrolysate activates cAMP signaling and hypothalamic neurotransmitter synthesis in pigs

“…24 Elevated brain tryptophan and tyrosine levels were strongly associated with increased 5-HT and dopamine concentrations, respectively. 25,26 Consistent with this, SPH infusion also increased dopamine concentration without affecting 5-HT concentration in the hypothalamus. Therefore, the synthesis of dopamine, but not 5-HT, in the hypothalamus was promoted by SPH.…”

Ordering Knowledge in the Markers of Psychiatric/Mental Disorders

“…As different known neurotransmitters can modulate each other, e.g., DA, 5HT, GL, etc., various theories with neuroimaging changes/markers have appeared in the literature [49][50][51]. Of them, glutamate seems to be the most important neurotransmitter, as it is present in over 90% of all brain synapses.…”

Tratamientos coadyuvantes y su impacto en la flexibilidad cognitiva de adultos con psicopatología diversa: una revisión sistemática exploratoria

“…No se encontraron diferencias significativas al momento de evaluar con la prueba de Stroop (p = 0.872); sin embargo, se identificó que los participantes tuvieron peor rendimiento en una prueba de cambio de tarea tras tomar ácido gamma aminobutírico ya sea por sí mismo o en combinación con la tirosina (F = 5.32; p = 0.026). 17 Seguidamente, Fortier y colaboradores realizaron un ensayo en el cual integraron a 122 adultos mayores con deterioro cognitivo leve, quienes recibieron una bebida cetogénica con ácidos grasos de cadena ramificada. Los participantes que tomaron el TC tuvieron menos errores en comparación con aquellos que ingirieron un placebo al momento de ser evaluados en la prueba de Trazo (p = 0.017).…”