Journal of Neuroscience, Vol 12, 1275-1279, Copyright © 1992 by Society for Neuroscience
Differential localization of G-proteins Gi and Go in the accessory olfactory bulb of the rat
H Shinohara, T Asano and K Kato
Department of Biochemistry, Institute for Developmental Research, Aichi Prefectural Colony, Japan.
To clarify the functional differences among G-proteins, we investigated the
localization of Gi and Go in the olfactory bulb of rats by both
immunohistochemical and immunochemical techniques, using purified
antibodies specific to the alpha-subunits of Gi1 (Gi1 alpha), Gi2 (Gi2
alpha), and Go (Go alpha), respectively. We found that Gi2 alpha is
localized exclusively in the accessory olfactory bulb, but it is present at
only low levels in the main olfactory bulb. The unique pattern of
immunoreactivity specific for Gi2 alpha and Go alpha within the glomeruli
of the accessory olfactory bulb and the results of immunoassays indicate
that the accessory olfactory bulb is divided into two parts: the anterior
region is rich in Gi2, while the posterior region is rich in Go. These
findings suggest that the accessory olfactory bulb has two different
functions. In addition, we found that the concentration of Gi2 alpha in the
accessory olfactory bulb increases during puberty and reaches the adult
level at 12 weeks after birth, while that in the main olfactory bulb
remains constant. By contrast, the concentrations of Go alpha in the
accessory olfactory bulb and the main olfactory bulb increase with similar
kinetics. These findings suggest that Gi2 is a key protein in signal
transduction in the accessory olfactory bulb, and increases in its level
seem to be related to sexual maturation.