SEROTONIN(1A) RECEPTORS ARE EXPRESSED BY A SUBPOPULATION OF CHOLINERGIC NEURONS IN THE RAT MEDIAL SEPTUM AND DIAGONAL BAND OF BROCA - A DOUBLE IMMUNOCYTOCHEMICAL STUDY
Hk. Kia et al., SEROTONIN(1A) RECEPTORS ARE EXPRESSED BY A SUBPOPULATION OF CHOLINERGIC NEURONS IN THE RAT MEDIAL SEPTUM AND DIAGONAL BAND OF BROCA - A DOUBLE IMMUNOCYTOCHEMICAL STUDY, Neuroscience, 74(1), 1996, pp. 143-154
The possible colocalization of 5-hydroxytryptamine(1A) receptors and c
holine acetyltransferase in the same neurons of the medial septum and
diagonal band of Broca was investigated using double immunocytochemica
l techniques, either on the same section or on adjacent thin sections
of the rat brain. The presence of both antigens in the same neurons wa
s demonstrated at the light and electron microscopic levels. The propo
rtion of cholinergic neurons that express 5-hydroxytryptamine(1A) rece
ptors was similar in the different parts of the septal complex (around
25%). By contrast, the proportion of 5-hydroxytryptamine(1A) receptor
-positive neurons also exhibiting choline acetyltransferase immunoreac
tivity was much higher (40-44%) in the dorsal and ventral groups of ch
olinergic cells, than in the intermediate group (18%). In line with th
e topographical distribution of cholinergic projections, this result p
oints out the potential involvement of 5-hydroxytryptamine(1A) recepto
rs in the control of the septohippocampal cholinergic projection by se
rotonin. This connection might be relevant to learning and memory, and
in the appearance of age-dependent or neurodegenerative cognitive def
icits, which have been shown to involve alterations in both the seroto
ninergic and the cholinergic systems. Copyright (C) 1996 Published by
Elsevier Science Ltd.