Columnar activity regulates astrocytic beta-adrenergic receptor-like immunoreactivity in V1 of adult monkeys.

Abstract

Recent results indicate that astrocytic beta-adrenergic receptors (beta AR) participate in noradrenergic modulation of synaptic activity. In this study, we sought to examine whether neural activity can, in turn, regulate astrocytic beta AR. To address this question, an antiserum that recognizes beta-adrenergic receptors (beta AR) specifically in astrocytes was used to assess the distribution of the receptors across ocular dominance columns in V1 of two monocular and four visually intact adult monkeys. Cytochrome oxidase histochemistry (CO) was used to identify the position of the cortical laminae and of the ocular dominance columns receiving visual inputs from the intact and enucleated eyes. This stain revealed the expected pattern within V1 of monocular monkeys--i.e. darker and lighter bands of equal widths (ca. 500 microns) spanning laminae 4-6, each associated with larger and smaller blobs, respectively, in lamina 2/3. Alignment of CO sections with adjacent sections stained for astrocytic beta AR by the immunoperoxidase method revealed intense beta AR-like immunoreactivity (beta AR-li) in the superficial laminae, a slightly weaker staining in the infragranular laminae and weakest staining in lamina 4C. Within lamina 4C, a prominent striped pattern was evident. The darker bands of the stripe closely matched widths and positions of the lighter CO columns associated with the enucleated eye. On the other hand, immunocytochemical staining for the astrocytic intermediate filament protein, GFAP, within V1 of monocular monkeys revealed no inter-columnar difference in the density of astrocytic cell bodies or processes. Nissl stain also revealed no overt inter-columnar differences in cell density.(ABSTRACT TRUNCATED AT 250 WORDS)