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Localization of α7 nicotinic receptor subunit mRNA and α‐bungarotoxin binding sites in developing mouse somatosensory thalamocortical system
Author(s) -
Bina Keshavan G.,
Guzman Patricia,
Broide Ron S.,
Leslie Frances M.,
Smith Martin A.,
O'Dowd Diane K.
Publication year - 1995
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.903630212
Subject(s) - biology , barrel cortex , thalamus , bungarotoxin , somatosensory system , acetylcholine receptor , nicotinic agonist , in situ hybridization , neuroscience , receptor , messenger rna , cerebral cortex , cortex (anatomy) , microbiology and biotechnology , medicine , endocrinology , genetics , gene
Previous studies in rat, showing a transient pattern of expression of the α7 nicotinic acetylcholine receptor in the ventrobasal thalamus and barrel cortex during the first 2 postnatal weeks, suggest that these receptors may play a role in development of the thalamocortical system. In the present study, in situ hybridization and radiolabeled ligand binding were employed to examine the spatiotemporal distribution of α7 mRNA and α‐bungarotoxin binding sites in the thalamocortical pathway of mouse during early postnatal development. As in the rat, high levels Of α7 mRNA and α‐bungarotoxin binding sites are present in the barrel cortex of mouse during the first postnatal week. Both α7 mRNA and its receptor protein are observed in all cortical laminae, with the highest levels seen in the compact cortical plate, layer IV, and layer VI. When viewed in a tangential plane, α7 mRNA and α‐bungarotoxin binding sites delineate a whisker‐related barrel pattern in layer IV by P3–5. Quantitative analysis reveals a dramatic decrease in the levels of expression of α7 mRNA and α‐bungarotoxin binding sites in the cortex by the end of the second postnatal week. Unlike in the rat, only low levels of α7 mRNA or α‐bungarotoxin binding sites are present in the ventrobasal complex of the mouse thalamus. The broad similarities between the thulamocurticul development of rat and mouse taken together with the present results suggest that α7 receptors located on cortical neurons, rather than on thalamic neurons, play a role in mediating aspects of thalamocortical development. © 1995 Wiley‐Liss, Inc.