TY - JOUR
T1 - MGlu5 antagonism impairs exploration and memory of spatial and non-spatial stimuli in rats.
AU - Christoffersen, Gert Rene Juul
AU - Simonyi, Agnes
AU - Schachtman, Todd R.
AU - Clausen, Bettina
AU - Clement, David
AU - Bjerre, Vicky Karin
AU - Mark, Louise T.
AU - Reinholdt, Mette
AU - Schmidt-Rasmussen, Kati
AU - Zink, Lena V. B.
N1 - Keywords: mGlu5 receptor; Antagonist; MPEP; Rat; Exploration; Maze learning; Object recognition; Prelimbic cortex
PY - 2008
Y1 - 2008
N2 - Metabotropic glutamate receptor subtype 5 (mGlu5) has been implicated in memory processing in some but not all learning tasks. The reason why this receptor is involved in some tasks but not in others remains to be determined. The present experiments using rats examined effects of the mGlu5-antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) - applied systemically i.p. (1-10 mg/kg) or bilaterally into the prelimbic cortex (1-10 µg) - on the ability of rats to explore and remember new stimuli. A cross-maze, open field, and object recognition task were used to evaluate exploration and memory and it was found that: 1) Locomotion during exploration of spatial environments and exploration time at novel objects were reduced by i.p. but not by prelimbic administration of MPEP, 2) spatial short-term memory was impaired in cross-maze and object discrimination was reduced after both types of administration, 3) long-term retention of spatial conditioning in the cross-maze was inhibited after i.p. applications which 4) also inhibited spontaneous alternation performance during maze-exploration. Reduced exploratory locomotion and exploration time after i.p. injections may have contributed to the observed retention impairments. However, the fact that prelimbic administration of MPEP inhibited retention without reducing exploration shows that memory formation was also impacted directly by prelimbic mGlu5 in both spatial and non-spatial learning.
AB - Metabotropic glutamate receptor subtype 5 (mGlu5) has been implicated in memory processing in some but not all learning tasks. The reason why this receptor is involved in some tasks but not in others remains to be determined. The present experiments using rats examined effects of the mGlu5-antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) - applied systemically i.p. (1-10 mg/kg) or bilaterally into the prelimbic cortex (1-10 µg) - on the ability of rats to explore and remember new stimuli. A cross-maze, open field, and object recognition task were used to evaluate exploration and memory and it was found that: 1) Locomotion during exploration of spatial environments and exploration time at novel objects were reduced by i.p. but not by prelimbic administration of MPEP, 2) spatial short-term memory was impaired in cross-maze and object discrimination was reduced after both types of administration, 3) long-term retention of spatial conditioning in the cross-maze was inhibited after i.p. applications which 4) also inhibited spontaneous alternation performance during maze-exploration. Reduced exploratory locomotion and exploration time after i.p. injections may have contributed to the observed retention impairments. However, the fact that prelimbic administration of MPEP inhibited retention without reducing exploration shows that memory formation was also impacted directly by prelimbic mGlu5 in both spatial and non-spatial learning.
U2 - 10.1016/j.bbr.2008.03.032
DO - 10.1016/j.bbr.2008.03.032
M3 - Journal article
SN - 0166-4328
VL - 191
SP - 235
EP - 245
JO - Behavioural Brain Research
JF - Behavioural Brain Research
IS - 2
ER -