The effects of eticlopride on Morris water task performance in male and female rats neonatally treated with quinpirole.
BACKGROUND
Previous studies have shown that neonatal quinpirole treatment which results in long-term dopamine D2 receptor supersensitization (D2 receptor priming) produces cognitive deficits in preweanling and adult rats behaviorally tested on the Morris water task (MWT).


OBJECTIVE
This study was designed to analyze whether pretraining administration of the D2 antagonist eticlopride alleviates cognitive deficits produced by neonatal quinpirole treatment.


METHODS
Both male and female Sprague-Dawley rats were treated with quinpirole HCl (1 mg/kg) or saline from postnatal days 1 to 21. From P22 to P24, rats were tested on the place version of the MWT in which a hidden platform remains stationary throughout training. From P25 to P28, rats were tested on the match-to-place version of the MWT, and rats are given a pair of daily training trials to locate the hidden platform that was moved to a new location each day. Fifteen minutes before each training session, rats were intraperitoneally administered with eticlopride (0.01 or 0.02 mg/kg) or saline.


RESULTS
Pretraining eticlopride treatment alleviated cognitive deficits produced by neonatal quinpirole treatment in both male and female rats on the place version of the MWT, as well as in males tested on the match-to-place version of the MWT. However, there were no significant deficits produced by neonatal quinpirole treatment in females tested on the match-to-place version of the MWT, and control males demonstrated superiority over control females on this version of the task.


CONCLUSIONS
Pretraining administration of the dopamine D2 antagonist eticlopride alleviated cognitive deficits produced by neonatal quinpirole treatment. However, it appears that the dopamine D2 receptor may have a more important influence on cognitive performance in males than in females, which may be related to increased sensitivity of the D2 receptor in males.
Brown
Russell W
RW
Department of Psychology, East Tennessee State University, 100 C.R. Drive, Box 70649, Johnson City, TN 37614, USA. brown1@mail.etsu.edu
Thompson
Kimberly N
KN
Click
Ivy A
IA
Best
Razaria A C
RA
Thacker
Stephanie K
SK
Perna
Marla K
MK
D000818:Animals; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D019257:Quinpirole / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017448:Receptors, Dopamine D2 / Q000187:drug effects* / Q000502:physiology; D012457:Salicylamides / Q000494:pharmacology*; D012727:Sex Characteristics; D013550:Swimming
D017448:Receptors, Dopamine D2; D012457:Salicylamides; D019257:Quinpirole; C045989:eticlopride