D-Lactate inhibition of memory in a single trial discrimination avoidance task in the young chick.
L-Lactate is a metabolite possibly able to meet some neuronal energy demands. However, a clear role for L-lactate in behaviour remains elusive. Administration of the inactive isomer D-lactate (1.75 mM; ic), immediately post-training, resulted in a persistent retention loss from 40 min post-training when used in conjuction with a single trial discrimination avoidance task designed for the young chick. Furthermore, 1mM noradrenaline (ic) administered 20 min post-training overcame the retention loss induced by D-lactate. Although not directly demonstrated in the current study, it is plausible that D-lactate inhibited memory processing by competing with L-lactate for uptake into neurons. The time of onset of the retention loss induced by D-lactate is in accord with findings where the action of noradrenaline is inhibited. The successful challenge of D-lactate inhibition by a high concentration of noradrenaline may suggest a relationship by some unidentified mechanism.
Baker
K D
KD
School of Psychology, Psychiatry and Psychological Medicine, Monash University, 3800 Vic., Australia.
Edwards
T M
TM
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D002645:Chickens; D004193:Discrimination Learning / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004734:Energy Metabolism / Q000502:physiology*; D007536:Isomerism; D019344:Lactic Acid / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009638:Norepinephrine / Q000502:physiology; D012153:Retention, Psychology / Q000187:drug effects* / Q000502:physiology; D013997:Time Factors
D019344:Lactic Acid; D009638:Norepinephrine