G. Bruning et O. Liangos, TRANSIENT EXPRESSION OF THE SEROTONIN TRANSPORTER IN THE DEVELOPING MOUSE THALAMOCORTICAL SYSTEM, Acta histochemica, 99(1), 1997, pp. 117-121
The serotonin transporter was visualized in sections through the devel
oping mouse thalamus by autoradiography of [H-3]citalopram binding. In
late gestation, a high densitiy of transporter expression appeared in
the ventrobasal thalamic complex and medial geniculate body. During t
he first postnatal week, binding in these areas decreased to low level
s. A similar pattern of transient [3H]citalopram binding was observed
in the somatosensory cortex, although the rise and decline of labeling
occurred some days later. The density of the serotonergic innervation
in the ventrobasal thalamic complex is known to be very low during th
e entire developmental period. Therefore, these data suggest that the
serotonin transporter may be expressed transiently by thalamic neurons
projecting to the cerebral cortex (as a ''heterocarrier'') which are
capable of taking up serotonin in the somatosensory cortex. We propose
that serotonin may act temporarily as a ''false'' transmitter in thal
amocortical axons.