Journal of Neuroscience, Vol 14, 4064-4078, Copyright © 1994 by Society for Neuroscience
Unique profiles of the alpha 1-, alpha 2-, and beta-adrenergic receptors in the developing cortical plate and transient embryonic zones of the rhesus monkey
MS Lidow and P Rakic
Yale University School of Medicine, New Haven, Connecticut 06510.
Film receptor autoradiography was used to study the distribution of alpha
1-, alpha 2-, and beta-adrenergic receptors in the occipital lobe of
developing rhesus monkeys ranging in age from the 65th embryonic day (E65)
to adulthood (5 years of age). The study shows that each adrenergic
receptor subtype has a unique distribution in the cortical plate and
transient embryonic zones of the developing cerebral wall. For example,
alpha 1 receptors are prominent throughout the proliferative ventricular
and subventricular zones while alpha 2 receptors in the same zones form
three distinct bands interdigitated with three bands rich in beta sites.
There are also considerable temporal differences in the emergence of
adrenergic receptor subtypes in specific embryonic zones. For instance, the
high density of alpha 1 sites in the germinal zones occurs only in
conjunction with intensive proliferative activity. In contrast, beta
receptors emerge in these zones after the majority of cortical neurons have
been generated. The transient embryonic zones often display higher
densities of adrenergic sites than the cortical plate itself. In
particular, the subplate zone subjacent to the developing visual cortex
contains the highest density of alpha 2-adrenergic sites in the cerebral
wall throughout all prenatal ages studies. Finally, the regional
differences in the density of beta-adrenergic receptors are evident in the
subplate zone underlying the prospective striate and extrastriate cortex
before such differences emerge in the cortical plate. The early appearance,
unique pattern of distribution, and time-dependent changes of adrenergic
receptors in the transient embryonic zones suggest their involvement in the
regulation of the cortical development.