DEVELOPMENT AND REGULATION OF BETA-ADRENERGIC RECEPTORS IN KITTEN VISUAL-CORTEX - AN IMMUNOCYTOCHEMICAL AND AUTORADIOGRAPHIC STUDY

The developmental pattern and laminar distribution of beta(1), and bet a(2) adrenergic receptor subtypes were studied in cat visual cortex wi th autoradiography using [I-125]iodocyanopindolol as a ligand and also with immunocytochemistry using a monoclonal antibody directed against beta adrenergic receptors. In the primary visual cortex of adult cats , the laminar distributions of both beta(1), and beta(2) adrenergic re ceptors revealed by autoradiography were very similar, with concentrat ions in layers I, II, III and VI. In young kittens (postnatal days 1 a nd 10), fewer beta adrenergic receptors were present, and they were co ncentrated in the deep cortical layers (V-VI) and subcortical white ma tter. Between postnatal days 15 and 40, beta adrenergic receptors incr eased in density more quickly in the superficial layers than they did in the deep and middle cortical layers. By postnatal day 40, the adult pattern Was achieved, with two bands of intense binding in the superf icial and deep cortical layers and a lower density in layer IV. Immuno cytochemical techniques applied to adult cat cortex showed that beta a drenergic receptor-like immunoreactivity was found in different popula tions of neurons and glial cells. The immunoreactive neural cells were most dense in layers II, III and VI. About 50% of these immunoreactiv e neural cells were glial cells, primarily astrocytes. Immunoreactive pyramidal cells were mostly located in layers III and V. In layer IV, many stellate cells were stained. Immunoreactive astrocytes in the sub plate and white matter progressively increased in number during develo pment until adulthood. The pattern of laminar distribution and the dev elopmental process was not affected by interrupting noradrenergic inne rvation from locus ceruleous either before or after the critical perio d. However, when visual input was interrupted by lesions of the latera l geniculate nucleus in young kittens (postnatal day 10), the density of both beta adrenergic receptor subtypes decreased significantly in t he deep cortical layers. Lateral geniculate nucleus lesions in adult c ats resulted in a pronounced decrease in beta adrenergic receptor dens ity in layer IV.