Thorn apparatus

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The spine apparatus , even Spine apparatus (of English. Spine apparatus called), is an organelle that is in the spinous processes of dendrites in certain populations of neurons found. This is an area of ​​the smooth endoplasmic reticulum that lies within the heads of thorn processes and is important for the development of synaptic plasticity , especially in long-term potentiation .

Occurrence

The thorn apparatus is only found in some of the nerve cells that carry the spinous process and typically in mushroom-shaped thorn processes. The synaptopodine required for the development of the spine apparatus is formed in different regions of the cerebrum . The thorn apparatus in nerve cells of the hippocampus has been examined particularly well . A third of the granule cells of the dentate gyrus and about 20% of the neurons in the CA1 region of the hippocampus have a spine apparatus, and it can also be found in the CA3 region.

function

The thorn apparatus plays a role in long-term potentiation, primarily as a calcium store. In the absence of the spine apparatus, when glutamate is released at the synapse, there is less calcium influx into the affected neuron and less incorporation of an ionotropic glutamate receptor ( AMPA receptor ) into the postsynaptic membrane. The spine apparatus is not only involved in long-term potentiation, but also in long-term depression . This is mediated via a metabotropic glutamate receptor . Synaptic plasticity is essential for learning. For example, mice that lack the synaptopodine gene and therefore lack a functional thorn apparatus show deficits in learning and memory tasks.

Individual evidence

  1. ↑ Peter Jedlicka, Stephan W. Schwarzacher, Raphael Winkels, Friederike Kienzler, Michael Frotscher, Clive R. Bramham, Christian Schultz, Carlos Bas Orth, Thomas Deller: 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 . In: Hippocampus . tape 19 , no. 2 , 2009, p. 130-140 , doi : 10.1002 / hipo.20489 , PMID 18767067 .
  2. ^ Menahem Segal, Andreas Vlachos, Eduard Korkotian: The Spine Apparatus, Synaptopodin, and Dendritic Spine Plasticity . In: Neuroscientist . tape 16 , no. 2 , 2010, p. 125-133 , doi : 10.1177 / 1073858409355829 , PMID 20400711 .
  3. ↑ Peter Mundel, Hans W. Heid, Thomas M. Mundel, Meike Krüger, Jochen Reiser, and Wilhelm Kriz: Synaptopodin: An Actin-associated Protein in Telencephalic Dendrites and Renal Podocytes . In: Journal of Cell Biology . tape 139 , no. 1 , 1997, p. 193-204 , doi : 10.1177 / 1073858409355829 , PMID 9314539 .
  4. ↑ Niklaus Holbro, Åsa Grunditz, Thomas G. Oertner: Differential distribution of endoplasmic reticulum controls metabotropic signaling and plasticity at hippocampal synapses . In: PNAS . tape 16 , no. 2 , 2009, p. 15055-15060 , doi : 10.1073 / pnas.0905110106 , PMID 19706463 .
  5. ↑ Thomas Deller, Martin Korte, Sophie Chabanis, Alexander Drakew, Herbert Schwegler, Giulia Good Stefani, Aimee Zuniga, Karin Schwarz, Tobias Bonhoeffer, Rolf Zeller, Michael Frotscher, Peter Mundel: Synaptopodin-deficient mice lack a spine apparatus and show deficits in synaptic plasticity . In: PNAS . tape 100 , no. 18 , 2003, p. 10494-10499 , doi : 10.1073 / pnas.1832384100 , PMID 12928494 .