title: Impairment of in vivo theta-burst long-term potentiation and network excitability in the dentate gyrus of synaptopodin-deficient mice lacking the spine apparatus and the cisternal organelle.
abstract: The function of the spine apparatus in dendritic spines and the cisternal organelles in axon initial segments is little understood. The actin-associated protein, synaptopodin, is essential for the formation of these organelles which are absent in synaptopodin -/- mice. Here, we used synaptopodin -/- mice to explore the role of the spine apparatus and the cisternal organelle in synaptic plasticity and local circuit excitability in response to activation of the perforant path input to the dentate gyrus in vivo. We found impaired long-term potentiation following theta-burst stimulation, whereas tetanus-evoked LTP was unaffected. Furthermore, paired-pulse inhibition of the population spike was reduced and granule cell excitability was enhanced in mutants, hence revealing an impairment of local network inhibition. In summary, our data represent the first electrophysiological evidence that the lack of the spine apparatus and the cisternal organelle leads to a defect in long-term synaptic plasticity and alterations in local circuit control of granule cell excitability under adult in vivo conditions.
authors.affiliation: Department of Clinical Neuroanatomy, Goethe-University of Frankfurt, Frankfurt am Main, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Jedlicka
authors.forename: Stephan W
authors.initials: SW
authors.lastname: Schwarzacher
authors.forename: Raphael
authors.initials: R
authors.lastname: Winkels
authors.forename: Friederike
authors.initials: F
authors.lastname: Kienzler
authors.forename: Michael
authors.initials: M
authors.lastname: Frotscher
authors.forename: Clive R
authors.initials: CR
authors.lastname: Bramham
authors.forename: Christian
authors.initials: C
authors.lastname: Schultz
authors.forename: Carlos
authors.initials: C
authors.lastname: Bas Orth
authors.forename: Thomas
authors.initials: T
authors.lastname: Deller