NDA@SZTAKI

Quantitative ultrastructural analysis of basket and axo-axonic cell terminals in the mouse hippocampus

Takács, Virág

Szőnyi, András

Freund, Tamás

Nyíri, Gábor

Gulyás, Attila

Springer

2015

RC Internal medicine / belgyógyászat

Three functionally different populations of perisomatic interneurons establish GABAergic synapses on hippocampal pyramidal cells: parvalbumin (PV)-containing basket cells, type 1 cannabinoid receptor (CB1)-positive basket cells both of which target somata, and PV-positive axo-axonic cells that innervate axon initial segments. Using electron microscopic reconstructions, we estimated that a pyramidal cell body receives synapses from about 60 and 140 synaptic terminals in the CA1 and CA3 area, respectively. About 60 % of these terminals were PV positive, whereas 35-40 % of them were CB1 positive. Only about 1 % (CA1) and 4 % (CA3) of the somatic boutons were negative for both markers. Using fluorescent labeling, we showed that most of the CB1-positive terminals expressed vesicular glutamate transporter 3. Reconstruction of somatic boutons revealed that although their volumes are similar, CB1-positive boutons are more flat and the total volume of their mitochondria was smaller than that of PV-positive boutons. Both types of boutons contain dense-core vesicles and frequently formed multiple release sites on their targets and innervated an additional soma or dendrite as well. PV-positive boutons possessed small, macular synapses; whereas the total synaptic area of CB1-positive boutons was larger and formed multiple irregular-shaped synapses. Axo-axonic boutons were smaller than somatic boutons, had only one synapse and their ultrastructural parameters were closer to those of PV-positive somatic boutons. Our results represent the first quantitative measurement-using a highly reliable method-of the contribution of different cell types to the perisomatic innervation of pyramidal neurons, and may help to explain functional differences in their output properties.

angol

Article

PeerReviewed

info:eu-repo/semantics/article

text

http://real.mtak.hu/25501/1/Nyiri_quantitativ_u.pdf

Takács, Virág and Szőnyi, András and Freund, Tamás and Nyíri, Gábor and Gulyás, Attila (2015) Quantitative ultrastructural analysis of basket and axo-axonic cell terminals in the mouse hippocampus. BRAIN STRUCTURE AND FUNCTION, 220 (2). pp. 919-940. ISSN 1863-2653

http://real.mtak.hu/25501/

MTMT:2506934; doi:10.1007/s00429-013-0692-6