Plasticity after microinjection of kainic acid (KA) into the adult rat whis
ker barrel cortex was investigated with immunohistochemical staining of pho
sphorylated growth-associated protein (GAP)-43. After mapping the barrel co
rtex with the technique of intrinsic signal optical imaging, a small volume
of KA was injected into one barrel. Rats were sacrificed at 2 days, 3 days
, 1 week, and 6 weeks after lesioning. GAP-43 staining demonstrated intense
immunoreactivity (IR) at the injected barrel which spread to the inter-bar
rel septa and the surrounding barrels. Elevated IR of GAP-43 was visible 2
days after KA injection, and increased gradually at least 6 weeks following
the lesion. This model has the possibility of offering a simple and reliab
le tool for studying cortical plasticity. NeuroReport 11:1603-1605 (C) 2000
Lippincott Williams & Wilkins.