Changes in filipin-sterol binding in the rat cingulate cortex after the administration of antidepressant drugs. A freeze-fracture study.

The amount of cholesterol in cell membranes of cingulate cortex nerve cells from rats treated with Imipramine (tricyclic antidepressant drug) or mianserin (non-tricyclic antidepressant) was investigated using filipin-sterol binding and freeze-fracture. The number of filipin-sterol complexes decreased within membranes of neurons from cingulate cortex chronically treated with imipramine or mianserin. These results suggest that the decreased content of cholesterol causes the cell membrane to become more fluid. This increased fluidity of the cell membrane may play an important role in regulating the interaction of transmitters and drugs with their membrane receptors.