Article date: 1992/9/28
PubMed ID: 1333220
Journal name: Behavioural brain research (ISSN: 0166-4328)
A neurochemical study of the transsynaptic interactions established between septal GABAergic interneurones and cholinergic septo-hippocampal neurones was conducted using mice. The effects of acute in vivo injections of either muscimol (20-500 ng/0.2 microliter), bicuculline (100 ng-1 micrograms/0.2 microliter) or saline vehicle (0.2 microliter) into the medial septum on septo-hippocampal cholinergic activity were evaluated using measures of hippocampal high affinity choline uptake at 30 min post-injection in two main groups of mice. The first (quiet control) remained in their home cages during the post-injection period whereas the second (active) were submitted, 10 min following injection to a 20-min period of spatial working memory testing in an 8-arm radial maze. Intraseptal injections of either muscimol or bicuculline produced significant (25-50%) inhibition of hippocampal cholinergic activity in quiet conditions (basal) as compared to intact or saline-injected mice. In the active groups, whereas memory testing induced significant cholinergic activation (+15-20%) in intact and saline injected mice at 30 s post-test no significant memory testing-induced activation was observed in either muscimol or bicuculline-injected mice at any dose. The role of septal GABAergic interneurones in the indirect transsynaptic control over the basal and activated states of septo-hippocampal cholinergic activity is discussed with respect to the concept that these complex neuronal interactions contribute to the physiological mechanisms involved in the modulation of working memory performance.
Author List: Durkin T P
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Receptors, GABA-A; Muscimol; gamma-Aminobutyric Acid; Bicuculline;
Mesh terms: Animals; Bicuculline/pharmacology; Brain Mapping; Cholinergic Fibers/drug effects; Discrimination Learning/drug effects; Dose-Response Relationship, Drug; Exploratory Behavior/physiology; Hippocampus/drug effects; Injections; Male; Mental Recall/drug effects; Mice; Mice, Inbred BALB C; Muscimol/pharmacology; Neural Pathways/drug effects; Orientation/drug effects; Receptors, GABA-A/drug effects; Retention (Psychology)/drug effects; Septum Pellucidum/drug effects; Space Perception/drug effects; Substantia Innominata/drug effects; Synapses/drug effects; Synaptic Transmission/drug effects; gamma-Aminobutyric Acid/physiology;