Biomaterial Database

Injections of tacrine and scopolamine into the nucleus accumbens: opposing effects of immediate vs delayed posttrial treatment on memory of an open field. 2000

S Schildein, and J P Huston, and R K Schwarting

Institute of Physiological Psychology I, Center for Biological and Medical Research, Heinrich-Heine-Universität of Düsseldorf, Universitätsstrasse 1, Düsseldorf, 40225, Germany.

Using the paradigm of habituation learning in the open field, we tested the effects of microinjections of the nonspecific acetylcholine-esterase inhibitor tacrine (0.1, 1.0, 10.0 micrograms), and the muscarinic receptor antagonist scopolamine (0.1, 1.0, 10.0 micrograms) into the core of the nucleus accumbens. When injected immediately after the first exposure to the open field (posttrial), tacrine dose-dependently enhanced habituation of rearing behavior during the test on the following day, indicating a facilitation of memory. In contrast, scopolamine impaired habituation of rearing behavior at the two lower doses, but not at the highest dose. When scopolamine or tacrine (10.0 micrograms) was injected with a delay of 5 h after the learning trial, both drugs impaired habituation of rearing on the following day. The effects on locomotor activity differed from those on rearing behavior. Here, habituation on Day 2 was observed only in those animals which had received posttrial injections of vehicle or 10 micrograms of tacrine on the day before, whereas in animals which had received the two lower doses of tacrine, locomotor activity on Day 2 was not significantly decreased. In animals with posttrial treatment of scopolamine, locomotor activity on Day 2 was even enhanced, especially with the lower doses. No such effects were observed when scopolamine or tacrine (10.0 micrograms each) was injected with a delay of 5 h after the learning trial. These results show that cholinergic manipulations aimed at the nucleus accumbens can have substantial effects in this posttrial memory paradigm, which depend on drug, dose, and time of injection, and the specific kind of behavioral measure analyzed. Among others, the findings are discussed with respect to the role of muscarinic and nicotinergic cholinergic mechanisms in the nucleus accumbens on cognitive functions. They may be relevant, for example, for understanding the psychopathology of Alzheimer's disease, since the nucleus accumbens is one of the sites where cholinergic neurons are lost in this neurodegenerative disease.

UI	MeSH Term	Description	Entries
D007267	Injections	Introduction of substances into the body using a needle and syringe.	Injectables,Injectable,Injection
D008297	Male		Males
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009714	Nucleus Accumbens	Collection of pleomorphic cells in the caudal part of the anterior horn of the LATERAL VENTRICLE, in the region of the OLFACTORY TUBERCLE, lying between the head of the CAUDATE NUCLEUS and the ANTERIOR PERFORATED SUBSTANCE. It is part of the so-called VENTRAL STRIATUM, a composite structure considered part of the BASAL GANGLIA.	Accumbens Nucleus,Nucleus Accumbens Septi,Accumbens Septi, Nucleus,Accumbens Septus, Nucleus,Accumbens, Nucleus,Nucleus Accumbens Septus,Nucleus, Accumbens,Septi, Nucleus Accumbens,Septus, Nucleus Accumbens
D011939	Mental Recall	The process whereby a representation of past experience is elicited.	Recall, Mental
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D002800	Cholinesterase Inhibitors	Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.	Acetylcholinesterase Inhibitor,Acetylcholinesterase Inhibitors,Anti-Cholinesterase,Anticholinesterase,Anticholinesterase Agent,Anticholinesterase Agents,Anticholinesterase Drug,Cholinesterase Inhibitor,Anti-Cholinesterases,Anticholinesterase Drugs,Anticholinesterases,Cholinesterase Inhibitors, Irreversible,Cholinesterase Inhibitors, Reversible,Agent, Anticholinesterase,Agents, Anticholinesterase,Anti Cholinesterase,Anti Cholinesterases,Drug, Anticholinesterase,Drugs, Anticholinesterase,Inhibitor, Acetylcholinesterase,Inhibitor, Cholinesterase,Inhibitors, Acetylcholinesterase,Inhibitors, Cholinesterase,Inhibitors, Irreversible Cholinesterase,Inhibitors, Reversible Cholinesterase,Irreversible Cholinesterase Inhibitors,Reversible Cholinesterase Inhibitors
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006185	Habituation, Psychophysiologic	The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.	Habituation (Psychophysiology),Habituation, Psychophysiological,Psychophysiologic Habituation,Psychophysiological Habituation,Habituations (Psychophysiology)
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