[Effect of elimination of brain stem-septal connections on prolonged posttetanic changes in the hippocampus].
Comparative analysis of long-lasting effects of Schaffer's collaterals tetanization (15 Hz, 15 s) was performed in 61 extracellularly recorded units of the intact hippocampus (field CA1) and in 51 units after complete septo-hippocampal disconnection in chronic alert rabbits. The number of units with long-lasting potentiation (LLP) was significantly greater in the hippocampus deprived of brain stem-septal afferents (63%) as compared to the intact hippocampus (21%); the number of units with posttetanic depression was reduced (21% versus 34%). The mean level of LLP in the deafferentated hippocampus was significantly higher than in the intact hippocampus (mean 220% and 180% of control level; p less than 0,001), and its duration was greater. Conversely, the mean level of depression was lower in the deafferentated hippocampus than in the normal one (140% and 170% of control level; p less than 0,01). This increase of LLP may result from elimination of inhibitory influences of the brain stem-septal afferent input, and/or from sprouting of Schaffer's collaterals after deafferentation with increase in number of functional synapses.
D000818:Animals; D001369:Axons / Q000502:physiology; D001931:Brain Mapping; D001933:Brain Stem / Q000502:physiology*; D004558:Electric Stimulation; D006624:Hippocampus / Q000502:physiology*; D009433:Neural Inhibition; D009434:Neural Pathways / Q000502:physiology; D011817:Rabbits; D011930:Reaction Time / Q000502:physiology; D012688:Septum Pellucidum / Q000502:physiology*
Vliianie ustraneniia stvolovo-septal'nykh sviazeĭ na dlitel'nye posttetanicheskie izmeneniia v gippokampe.