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Selective cholinergic immunolesioning affects synaptic plasticity in developing visual cortex
Author(s) -
Kuczewski N.,
Aztiria E.,
Leanza G.,
Domenici L.
Publication year - 2005
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2005.04014.x
Subject(s) - long term potentiation , cholinergic , neuroscience , basal forebrain , synaptic plasticity , acetylcholine , visual cortex , cholinergic neuron , cholinergic fibers , biology , neurotransmission , long term depression , endocrinology , receptor , glutamate receptor , ampa receptor , biochemistry
Cholinergic neurotransmission is known to affect activity‐dependent plasticity in various areas, including the visual cortex. However, relatively little is known about the exact role of subcortical cholinergic inputs in the regulation of plastic events in this region during early postnatal development. In the present study, synaptic transmission and plasticity in the developing visual cortex were studied following selective immunotoxic removal of the basal forebrain cholinergic afferents in 4‐day‐old rat pups. The lesion produced dramatic cholinergic neuronal and terminal fibre loss associated with decreased mRNA levels for the M 1 and M 2 muscarinic receptors, as well as clear‐cut impairments of long‐term potentiation (LTP) in visual cortex slices. Indeed, after theta burst stimulation of layer IV a long‐term depression (LTD) instead of an LTP was induced in immunolesioned slices. This functional change appears to be due to the lack of cholinergic input as exogenous application of acetylcholine prevented the shift from LTP to LTD. In addition, lesioned rats showed an increased sensitivity to acetylcholine (ACh). While application of 20 µ m ACh produced a depression of the field potential in immunolesioned rat slices, in order to observe the same effect in control slices we had to increase ACh concentration to up to 200 µ m . Taken together, our results indicate that deprivation of cholinergic input affects synaptic transmission and plasticity in developing visual cortex, suggesting that the cholinergic system could play an active role in the refinement of the cortical circuitry during maturation.