Interneuronal growth and expression of interneuronal markers in visual cortex of mice with transgenic activation of Ras.
The synRas transgenic mice express constitutively activated Valin12-Harvey Ras in postnatal neocortical pyramidal neurons. This leads to somatodendritic hypertrophy, higher densities of spines and synapses, and an enhancement of synaptic long-term potentiation associated with an increased glutamate receptor-mediated activity. It was less clear how the interneurons respond to these alterations, and this prompted the quantitative assessment of interneuron neurochemistry. Interneurons rarely expressed the transgene, however, several interneuron types displayed a transient somatic hypertrophy. Furthermore, NPY mRNA expression was persistently increased as were the laminar percentages of labeled neurons. The expression of parvalbumin and voltage-gated potassium channels Kv3.1b/3.2 was unchanged. A significant decline of GAD-67, but not GAD-65, mRNA expressing neurons was observed in layer VI in animals older than P60. This suggested that subtle deficits in inhibition and enhanced excitation evoke the interneuronal changes in the synRastransgenic mouse cortex.
Patz
Silke
S
AG Entwicklungsneurobiologie, Fakultät für Biologie and Biotechnologie, ND 6/72, Ruhr-Universität, 44780 Bochum, Germany.
Colovic
Corinna
C
Wawro
Stefanie
S
Lafenetre
Pauline
P
Leske
Oliver
O
Heumann
Rolf
R
Schönfelder
Sabine
S
Tomaschewski
Jana
J
Räk
Andrea
A
Wahle
Petra
P
D000367:Age Factors; D000818:Animals; D049108:Cell Enlargement; D003712:Dendrites / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D006131:Growth Inhibitors / Q000235:genetics; D007395:Interneurons / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009433:Neural Inhibition / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000096:biosynthesis* / Q000235:genetics; D014793:Visual Cortex / Q000166:cytology / Q000378:metabolism* / Q000473:pathology
D006131:Growth Inhibitors; D016283:Proto-Oncogene Proteins p21(ras)