Fig. 2.

A, In situhybridization against the γ1 chain of laminin in the CA3 region of a P4 mouse hippocampus. The cell bodies of pyramidal neurons (PN) are stained (BV, blood vessel). The inset demonstrates a higher magnification confocal image of a labeled neuron (PN). Scale bars, 10 μm. B, CA1 region of the same section that lacks γ1 chain mRNA. Scale bar, 10 μm. C, Semithin section (1 μm) of a P4 untreated/uncut rat hippocampal slice that had been in culture for 24 hr and stained for the laminin γ1 chain. The cell bodies of pyramidal neurons (arrow) and their apical dendrites express laminin. Scale bar, 25 μm. D, E, EM immunohistochemical staining of the γ1 laminin chain (no heavy metal counterstain was used) in ultrathin sections taken from the same slice from which the 1 μm section was taken (BV, blood vessel; A, astrocytes). Note in D the intracellular laminin reactivity within the cytoplasm of a pyramidal neuron cell body. Note also the intense extracellular staining associated with astrocyte membranes (E). Scale bar, 1 μm.