Chronic imipramine diminishes the nuclear size of neurons in the locus coeruleus and cingular cortex but not in the hippocampus of the rat brain

The Locus Ceruleus Responds to Signaling Molecules Obtained from the CSF by Transfer through Tanycytes

“…This time frame is intermediate between previous reports that indicated changes in nuclear sizes of adult mammalian LoC neurons within Ͻ1 h (Bubenik and Monnier, 1972) or in the order of weeks of manipulations (Smialowska et al, 1988).…”

“…This privileged access of the LoC to the CSF is remarkably selective, as it is used by only a small number of molecules: NGF and urotensin-1 (a CRF family ligand), but not neurotrophin-3 (NT-3), fibroblast growth factor 2 (FGF2), or glial cell line-derived neurotrophic factor (GDNF). Remarkably, we show that the nuclear diameter of LoC neurons-a measure of LoC neuronal activity (Bubenik and Monnier, 1972;Smialowska et al, 1988)-is controlled by the amount of endogenous and exogenous NGF in the CSF. Our data reveal and characterize a novel interface of communication between the neurons in the third ventricle of some species (von Bartheld and Meyer, 1990), we performed an exhaustive search of the ependyma adjacent to the LoC.…”

“…No previous studies have examined the role of either exogenous or endogenous NGF in the CSF on the main producers of noradrenaline in the CNS, the LoC, and the possible route of how CSF-derived growth factors and hormones may influence this major CNS population. By using a karyometric and quantitative autoradiographic approach, we demonstrate not only that CSF-derived NGF controls avian LoC nuclear size, known to be linked to neuronal activity of the LoC (Bubenik and Monnier, 1972;Smialowska et al, 1988), but also that LoC neurons gain access to the NGF that is present within the CSF by using a novel mechanism: tanycyte-mediated extraction and transcytotic transfer of NGF. Importantly, while responses of the LoC to NGF are bird specific, the tanycyte-LoC connection is also found in adult mammals (Felten et al, 1981b).…”

“…We chose karyometric studies of LoC neurons as a readout for assessment of LoC function (Bubenik and Monnier, 1972). It is well established that LoC neurons rapidly and reliably change their nuclear sizes with their level of activity; i.e., during sleep the nuclear size decreases, whereas arousal, stress, or treatment with antidepressive medication increases nuclear size (Bubenik and Monnier, 1972;Smialowska et al, 1988). These effects have been directly correlated with electrical activity (firing rates) of LoC neurons, as well as changes in the activity levels of tyrosine hydroxylase (Olpe and Jones, 1983;Racagni and Brunello, 1984).…”

Changes in the amount and distribution of neuronal alkaline and acid phosphatase after chronic exposure of cultures of cingulate cortex to antidepressant drugs

“…In addition to the well known receptor actions of antidepressants (Sugrue, 1983;Sulser, 1983;Vetulani, 1984) there is some evidence to suggest that these drugs may also have intracellular actions (Albouz etal., 1982;Bal etal., 1987;Bal, 1989;Bal and Bird, 1990;Honegger et al, b, 1988Smialowska et al, 1988). We have previously shown that amitriptyline (AMI), desipramine (DMI), mianserin (MIA) and citalopram (CIT) affect the ultrastructure of nerve cells when dissociated cultures of embryonic rat cingulate cortex are chronically exposed to these drugs (Bal and Bird, 1990).…”