The opposite effects of cysteamine on the acquisition of two different tasks in mice are associated with bidirectional testing-induced changes in hippocampal adenylyl cyclase activity.
The hypothesis of a role for hippocampal somatostatin (SS-14) in learning and memory processes was further examined by means of 2 selective learning tasks that were previously shown to be either impaired (spatial discrimination task) or facilitated (barpressing task) by hippocampal lesions. Results showed that subcutaneous injections of cysteamine (160 mg/kg) (a) impaired acquisition of the spatial task while producing an opposite (i.e., facilitative) effect on acquisition of the barpressing task and (b) produced an up regulation of hippocampal adenylyl cyclase (AC) activity, which was antagonized by spatial discrimination training but enhanced by training in the barpressing task. Moreover, opposite task-dependent training-induced changes in hippocampal AC activity was observed in saline-treated mice. These results suggest that bidirectional regulatory mechanisms of hippocampal function involving both SS-14 and ACs may occur as a function of the type of learning.
Guillou
J L
JL
Laboratoire de Neurosciences Comportementales et Cognitives, Université de Bordeaux I, Talence, France. memo@neurocog.u-bordeaux.fr
Micheau
J
J
Jaffard
R
R
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D003543:Cysteamine / Q000494:pharmacology*; D004193:Discrimination Learning / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D006727:Hormone Antagonists / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology*; D008568:Memory / Q000145:classification / Q000187:drug effects / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009949:Orientation / Q000187:drug effects / Q000502:physiology; D013004:Somatostatin / Q000502:physiology*; D013028:Space Perception / Q000187:drug effects / Q000502:physiology; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology
D006727:Hormone Antagonists; D013004:Somatostatin; D003543:Cysteamine; D000262:Adenylyl Cyclases