The influence of chronic lithium administration on deafferentation-induced cellular changes in the chick cochlear nucleus. 2008

A L Bush, and K L Carzoli, and R L Hyson
Department of Psychology, The Florida State University, 1107 West Call Street, Tallahassee, FL 32306-4301, USA.

The avian brainstem serves as a useful model system to address the question of how afferent activity influences viability of target neurons. Approximately 20-30% of neurons in the chick cochlear nucleus, nucleus magnocellularis (NM) die following deafferentation (i.e. deafness produced by cochlea removal). Previous studies have identified cellular events that occur within hours following cochlea removal, which are thought to lead to the ultimate death of NM neurons. We have recently shown that chronic lithium treatment increases neuronal survival following deafferentation. To assess where in the cell death cascade lithium is having its effect, we evaluated some of the early deafferentation-induced cellular changes in NM neurons. Lithium did not affect deafferentation-induced changes that occur across the entire population of NM neurons. There were still deafferentation-induced increases in intracellular calcium concentrations and early changes in the ribosomes, as indicated by Y10b immunolabeling. Lithium did, however, affect changes that are believed to be indicative of the subpopulation of NM neurons that will eventually die. Ribosomes recovered in all of the deafferented NM neurons (as assessed by Y10b labeling) by 10 h following cochlea removal in subjects pretreated with lithium, while a subpopulation of the NM neurons in saline-treated subjects showed dramatic reduction in Y10b labeling at that time. Lithium treatment also prevented the robust upregulation of b cell leukemia/lymphoma-2 (Bcl-2) mRNA that is observed in a subpopulation of deafferented NM neurons 6 h following cochlea removal.

UI MeSH Term Description Entries
D007150 Immunohistochemistry Histochemical localization of immunoreactive substances using labeled antibodies as reagents. Immunocytochemistry,Immunogold Techniques,Immunogold-Silver Techniques,Immunohistocytochemistry,Immunolabeling Techniques,Immunogold Technics,Immunogold-Silver Technics,Immunolabeling Technics,Immunogold Silver Technics,Immunogold Silver Techniques,Immunogold Technic,Immunogold Technique,Immunogold-Silver Technic,Immunogold-Silver Technique,Immunolabeling Technic,Immunolabeling Technique,Technic, Immunogold,Technic, Immunogold-Silver,Technic, Immunolabeling,Technics, Immunogold,Technics, Immunogold-Silver,Technics, Immunolabeling,Technique, Immunogold,Technique, Immunogold-Silver,Technique, Immunolabeling,Techniques, Immunogold,Techniques, Immunogold-Silver,Techniques, Immunolabeling
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D002642 Chick Embryo The developmental entity of a fertilized chicken egg (ZYGOTE). The developmental process begins about 24 h before the egg is laid at the BLASTODISC, a small whitish spot on the surface of the EGG YOLK. After 21 days of incubation, the embryo is fully developed before hatching. Embryo, Chick,Chick Embryos,Embryos, Chick
D003051 Cochlea The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH. Cochleas
D005456 Fluorescent Dyes Chemicals that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags. Flourescent Agent,Fluorescent Dye,Fluorescent Probe,Fluorescent Probes,Fluorochrome,Fluorochromes,Fluorogenic Substrates,Fluorescence Agents,Fluorescent Agents,Fluorogenic Substrate,Agents, Fluorescence,Agents, Fluorescent,Dyes, Fluorescent,Probes, Fluorescent,Substrates, Fluorogenic
D000344 Afferent Pathways Nerve structures through which impulses are conducted from a peripheral part toward a nerve center. Afferent Pathway,Pathway, Afferent,Pathways, Afferent
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
D012270 Ribosomes Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION. Ribosome
D012333 RNA, Messenger RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm. Messenger RNA,Messenger RNA, Polyadenylated,Poly(A) Tail,Poly(A)+ RNA,Poly(A)+ mRNA,RNA, Messenger, Polyadenylated,RNA, Polyadenylated,mRNA,mRNA, Non-Polyadenylated,mRNA, Polyadenylated,Non-Polyadenylated mRNA,Poly(A) RNA,Polyadenylated mRNA,Non Polyadenylated mRNA,Polyadenylated Messenger RNA,Polyadenylated RNA,RNA, Polyadenylated Messenger,mRNA, Non Polyadenylated
D016257 Fura-2 A fluorescent calcium chelating agent which is used to study intracellular calcium in tissues. Fura 2

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