Neonatal serotonin (5-HT) depletion does not affect spatial learning and memory in rats.
BACKGROUND
Extensive previous research has suggested a role for serotonin (5-HT) in learning and memory processes, both in healthy individuals and pathological disorders including depression, autism and schizophrenia, most of which have a developmental onset. Since 5-HT dysfunction in brain development may be involved in disease etiology, the present investigation assessed the effects of neonatal 5-HT depletion on spatial learning and memory in the Morris water maze (MWM).


METHODS
Three days old Sprague-Dawley rats were pretreated with desipramine (20 mg/kg) followed by an intraventricular injection of the selective 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT, 70 μg). Three months later rats were tested in the MWM.


RESULTS
Despite a severe and permanent decrease (80-98%) in hippocampal, prefrontal and striatal 5-HT levels, treatment with 5,7-DHT caused no spatial learning and memory impairment.


CONCLUSIONS
Limited involvement of chronic 5-HT depletion on learning and memory does not exclude the possibility that this neurotransmitter has an important neuromodulatory role in these functions. Future studies will be needed to identify the nature of the compensatory processes that are able to allow normal proficiency of spatial learning and memory in 5-HT-depleted rats.
Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Krakowskie Przedmieście 26/28, PL 00-927 Warszawa, Poland.
Agnieszka
A
Piechal
Kamilla
K
Blecharz-Klin
Edyta
E
Wyszogrodzka
Paulina
P
Kołomańska
Paulina
P
Rok-Bujko
Paweł
P
Krząścik
Wojciech
W
Kostowski
Ewa
E
Widy-Tyszkiewicz
Małgorzata
M
Filip
Roman
R
Stefański
D015115:5,6-Dihydroxytryptamine / Q000031:analogs & derivatives / Q000633:toxicity; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D015306:Biogenic Monoamines / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D003404:Creatinine / Q000031:analogs & derivatives / Q000633:toxicity; D003891:Desipramine / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D017397:Prefrontal Cortex / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000633:toxicity; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology*; D013550:Swimming
D015306:Biogenic Monoamines; D012702:Serotonin Antagonists; D012701:Serotonin; C078441:5,7-dihydroxytryptamine creatinine; D003404:Creatinine; D003891:Desipramine; D015115:5,6-Dihydroxytryptamine