Increased Synaptic Availability of Norepinephrine Following Desipramine is Not Essential for Increases in GR MRNA. Short Communication

Male Sprague-Dawley rats were treated for 7 days with the norepinephrine (NE) uptake inhibitors desipramine (DMI) or (+)-oxaprotiline or the inactive (-)-enantiomer of oxaprotiline. DMI, as previously reported, significantly increased hippocampal glucocorticoid receptor (GR) mRNA while the equipotent NE uptake inhibitor (+)-oxaprotiline like the inactive (-)-oxaprotiline did not alter hippocampal levels of GR mRNA. The results indicate that an increase in the synaptic availability of NE as a consequence of uptake inhibition is not responsible for the action of DMI on GR gene expression.