title: Alterations in calmodulin content in fractions of rat hippocampal slices during tetanic- and calcium-induced long-term potentiation.
abstract: The content of cytosolic and membrane-bound calmodulin was radioimmunologically determined in fractions of rat hippocampal slices 5 min to 7 hours after long-term potentiation (LTP) had been induced by tetanization or exposure of slices to 4 mM Ca++. In light of concepts presuming multistage dynamics in LTP development as reflecting different cellular mechanisms, similar patterns of calmodulin alterations were observed with both models: The alterations in calmodulin content occurred during the early phase(s) of LTP development and continued for two and one hours during tetanic- and calcium-induced LTP, respectively. Thus, 5-30 min after LTP elicitation, membrane-bound calmodulin increased while cytosolic calmodulin diminished and, inversely, 30 min later an increase in cytosolic and decrease in membrane-bound calmodulin were observed. Consequently, the present results indicate that calmodulin was involved in the early phases(s) of LTP development in terms of a two-step translocation sequence. Hence, calmodulin translocation within both intracellular compartments may reflect the involvement of Ca++-calmodulin-dependent intraneuronal metabolic processes which might induce and/or temporarily maintain neuronal functional changes occurring immediately after repeated or intense stimulation of synaptic functions.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Medizinischen Akademie, Magdeburg, German Democratic Republic.
authors.forename: N S
authors.initials: NS
authors.lastname: Popov
authors.forename: K G
authors.initials: KG
authors.lastname: Reymann
authors.forename: K
authors.initials: K
authors.lastname: Schulzeck
authors.forename: S
authors.initials: S
authors.lastname: Schulzeck
authors.forename: H
authors.initials: H
authors.lastname: Matthies
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002147:Calmodulin / Q000032:analysis*; D002462:Cell Membrane / Q000032:analysis; D003600:Cytosol / Q000032:analysis; D006624:Hippocampus / Q000032:analysis* / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002147:Calmodulin; D002118:Calcium