Journal of Neuroscience, Vol 6, 2208-2214, Copyright © 1986 by Society for Neuroscience
Deafferentation elicits increased dopamine-sensitive adenylate cyclase and receptor binding in the olfactory tubercle
RB Lingham and Z Gottesfeld
Removal of a major non-catecholaminergic output from the olfactory bulb
elicits sprouting of dopaminergic axons in the olfactory tubercle. The
functional consequences of this increased dopaminergic innervation are
presently not known. This study examined the question of whether lesion-
induced sprouting of dopaminergic axons is associated with changes in
dopamine-sensitive adenylate cyclase and dopamine receptor density in the
partially denervated olfactory tubercle. The results indicate that
dopamine- and NaF-stimulated adenylate cyclase activity increased as early
as 7 d, while forskolin-sensitive activity increased at 3 d and persisted
up to 20 d after lesioning; higher levels of GTP- and NaF- stimulated
enzyme activity were found in detergent extracts of olfactory tubercle
membranes from 20 d lesioned rats; higher levels of 3H-forskolin binding
were found in membranes from 14 and 20 d lesioned rats; and there was an
increase in dopamine receptor density, but not affinity, in olfactory
tubercle membranes from lesioned rats. The data indicate that
lesion-induced dopaminergic sprouting in the olfactory tubercle is
temporally coordinated with the increased formation of dopamine receptors,
both D1 and D2, the stimulatory guanine nucleotide regulatory protein (Ns)
and the catalytic subunit (C) of adenylate cyclase in the postsynaptic
membrane.