Embryonic amygdalar transplants in adult rats with motor cortex lesions: a molecular and electrophysiological analysis

Abstract

Transplants of embryonic nervous tissue ameliorate motor deficits induced by motor cortex lesions in adult animals. Restoration of lost brain functions has been recently shown in grafts of homotopic cortical origin, to be associated with a functional integration of the transplant after development of reciprocal host–graft connections. Nevertheless little is known about physiological properties or gene expression profiles of cortical implants with functional restorative capacity but no cortical origin. In this study, we show molecular and electrophysiological evidence supporting the functional development and integration of heterotopic transplants of embryonic amygdalar tissue placed into pre-lesioned motor cortex of adult rats. Grafts were analyzed 3 months post-transplantation. Using reverse transcriptase quantitative polymerase chain reaction, we found that key glutamatergic, GABAergic, and muscarinic receptors transcripts were expressed at different quantitative levels both in grafted and host tissues, but were all continuously present in the graft. Parallel sharp electrode recordings of grafted neurons in brain slices showed a regular firing pattern of transplanted neurons similar to host amygdalar pyramidal neurons. Synaptic connections from the adjacent host cortex on grafted neurons were electrophysiologically investigated and confirmed our molecular results. Taken together, our findings indicate that grafted neurons from a non-cortical, non-motor-related, but ontogenetical similar source, not only received functionally effective contacts from the adjacent motor cortex, but also developed electrophysiological and gene expression patterns comparable to host pyramidal neurons; suggesting an interesting tool for the field of neural repair and donor tissue in adults.

Amyloid-β(25-35) Modulates the Expression of GirK and KCNQ Channel Genes in the Hippocampus

“…For relative mRNA quantification C q values (C q , standard name for threshold cycle or crossing point value according to the Real-Time PCR Data Markup Language, RDML guidelines, [ 36 ]) were calculated in each sample set for reference and target genes. The expression of each target gene relative to a normalizing factor (a reference gene that was chosen accordingly to its stability; see section below) was calculated using the 2 −ΔCq method [ 37 , 38 ] as described by the manufacturer (Applied Biosystems: User Bulletin 2). Changes in gene expression through the time course were reported as percent changes relative to basal control expression at time zero (t = 0 min, i.e.…”

Infiltrating cells from host brain restore the microglial population in grafted cortical tissue

“…These studies have achieved remarkable results in showing that grafted neurons can successfully survive and synaptic connections can be established between the host and donor cells 1 2 3 . Importantly, grafted neurons are electrophysiologically active in responding to adjacent host cortex 4 5 6 , and the lost functions can be partially recovered after transplantation 7 8 9 .…”

Development and Maturation of Embryonic Cortical Neurons Grafted into the Damaged Adult Motor Cortex

“…In the past few years, the survival capacity of embryonic neurons transplanted in different regions of the adult brain has been demonstrated, and many studies have reported their repair potential at the neuroanatomical and functional levels (Lindvall et al, 1990 ; Plumet et al, 1993 ; Ebrahimi-Gaillard et al, 1995 ; Gaillard et al, 2007 , 2009 ; Santos-Torres et al, 2009 ; Thompson et al, 2009 ; Jiménez-Díaz et al, 2011 ; Lu et al, 2012 ; Klein et al, 2013 ).…”