AUTHOR=Gibbs Marie E., Hertz Leif 

TITLE=Serotonin mediation of early memory formation via 5-HT2B receptor-induced glycogenolysis in the day-old chick

JOURNAL=Frontiers in Pharmacology

VOLUME=Volume 5 - 2014

YEAR=2014

URL=https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2014.00054

DOI=10.3389/fphar.2014.00054

ISSN=1663-9812

ABSTRACT=Investigation of the effects of serotonin on memory formation in the chick revealed an action on at least two 5HT receptors. Serotonin injected intracerebrally produced a biphasic effect on memory consolidation with enhancement at low doses and inhibition at higher doses. The non-selective 5HT receptor antagonist methiothepin and the selective 5HT2B/C  receptor antagonist SB221284 both inhibited memory, suggesting actions of serotonin on at least 2 different receptor subtypes. The 5HT2B/C and astrocyte-specific 5-HT receptor agonists, fluoxetine and paroxetine, enhanced memory and the effect was attributed to glycogenolysis. Inhibition of glycogenolysis with a low dose of DAB prevented both serotonin and fluoxetine from enhancing memory during short-term memory but not during intermediate memory. The role of serotonin on the 5HT2B/C  receptor appears to involve glycogen breakdown in astrocytes during short-term memory, whereas other published evidence attributes the second period of glycogenolysis to noradrenaline.