Excitotoxic median raphe lesions aggravate working memory storage performance deficits caused by scopolamine infusion into the dentate gyrus of the hippocampus in the inhibitory avoidance task in rats. 2002

E Babar, and E Melik, and T Ozgunen
Division of Neurophysiology, Department of Physiology, Medical Faculty, University of Cukurova, Balcali-Adana, Turkey. ebarbar@mail.cu.edu.tr

The interactions between the median raphe nucleus (MRN) serotonergic system and the septohippocampal muscarinic cholinergic system in the modulation of immediate working memory storage performance were investigated. Rats with sham or ibotenic acid lesions of the MRN were bilaterally implanted with cannulae in the dentate gyrus of the hippocampus and tested in a light/dark step-through inhibitory avoidance task in which response latency to enter the dark compartment immediately after the shock served as a measure of immediate working memory storage. MRN lesion per se did not alter response latency. Post-training intrahippocampal scopolamine infusion (2 and 4 microg/side) produced a more marked reduction in response latencies in the lesioned animals compared to the sham-lesioned rats. Results suggest that the immediate working memory storage performance is modulated by synergistic interactions between serotonergic projections of the MRN and the muscarinic cholinergic system of the hippocampus.

UI MeSH Term Description Entries
D008297 Male Males
D008570 Memory, Short-Term Remembrance of information for a few seconds to hours. Immediate Recall,Memory, Immediate,Working Memory,Memory, Shortterm,Immediate Memories,Immediate Memory,Immediate Recalls,Memories, Immediate,Memories, Short-Term,Memories, Shortterm,Memory, Short Term,Recall, Immediate,Recalls, Immediate,Short-Term Memories,Short-Term Memory,Shortterm Memories,Shortterm Memory,Working Memories
D011903 Raphe Nuclei Collections of small neurons centrally scattered among many fibers from the level of the TROCHLEAR NUCLEUS in the midbrain to the hypoglossal area in the MEDULLA OBLONGATA. Caudal Linear Nucleus of the Raphe,Interfascicular Nucleus,Nucleus Incertus,Rostral Linear Nucleus of Raphe,Rostral Linear Nucleus of the Raphe,Superior Central Nucleus,Central Nucleus, Superior,Incertus, Nucleus,Nuclei, Raphe,Nucleus, Interfascicular,Nucleus, Raphe,Nucleus, Superior Central,Raphe Nucleus
D011930 Reaction Time The time from the onset of a stimulus until a response is observed. Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001362 Avoidance Learning A response to a cue that is instrumental in avoiding a noxious experience. Aversion Behavior,Aversion Learning,Aversive Behavior,Aversive Learning,Avoidance Behavior,Aversion Behaviors,Aversive Behaviors,Avoidance Behaviors,Behavior, Aversion,Behavior, Aversive,Behavior, Avoidance,Behaviors, Aversion,Behaviors, Aversive,Behaviors, Avoidance,Learning, Aversion,Learning, Aversive,Learning, Avoidance
D012601 Scopolamine An alkaloid from SOLANACEAE, especially DATURA and SCOPOLIA. Scopolamine and its quaternary derivatives act as antimuscarinics like ATROPINE, but may have more central nervous system effects. Its many uses include an anesthetic premedication, the treatment of URINARY INCONTINENCE and MOTION SICKNESS, an antispasmodic, and a mydriatic and cycloplegic. Hyoscine,Scopolamine Hydrobromide,Boro-Scopol,Isopto Hyoscine,Kwells,Scoburen,Scopace,Scopoderm TTS,Scopolamine Cooper,Transderm Scop,Transderm-V,Travacalm HO,Vorigeno,Boro Scopol,Transderm V
D012701 Serotonin A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator. 5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine
D017208 Rats, Wistar A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain. Wistar Rat,Rat, Wistar,Wistar Rats
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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