Evidence for localized and discrete roles for enkephalins during memory formation in the chick.
This study examined effects on memory formation produced by [Leu]enkephalin and [Met]enkephalin administration in 2 regions of the 2-day-old chick brain involved in memory formation: the intermediate medial hyperstriatum ventrale (IMHV) and the lobus parolfactorius (LPO). Basal concentrations of endogenous [Leu]enkephalin and [Met]enkephalin were determined for 5 brain regions, and effects of 1-trial peck-avoidance training on enkephalin concentrations were examined in the IMHV and LPO. [Leu]enkephalin was amnestic when administered in the IMHV but not in the LPO. In contrast, [Met]enkephalin may be amnestic when administered in the LPO but not in the IMHV. Training decreased [Met]enkephalin concentration in the LPO but not in the IMHV. Training had no effect on [Leu]enkephalin concentration in either the IMHV or the LPO. Thus, amnestic effects of [Leu]- or [Met]enkephalin administration are brain-region specific. Regional activity of endogenous [Met]enkephalin during memory formation is consistent with localized amnestic effects produced by [Met]enkephalin administration.
Colombo
P J
PJ
Department of Psychology, University of California, Berkeley, USA. pcolombo@email.unc.edu
Rivera
D T
DT
Martinez
J L
JL
Bennett
E L
EL
Rosenzweig
M R
MR
D000367:Age Factors; D000818:Animals; D001070:Appetitive Behavior / Q000502:physiology; D001362:Avoidance Learning / Q000502:physiology*; D001921:Brain / Q000254:growth & development / Q000502:physiology*; D001931:Brain Mapping; D002645:Chickens; D003214:Conditioning, Classical / Q000502:physiology; D004743:Enkephalin, Leucine / Q000502:physiology; D004744:Enkephalin, Methionine / Q000502:physiology; D004745:Enkephalins / Q000502:physiology*; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D013649:Taste / Q000502:physiology
D004745:Enkephalins; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine