EFFECTS OF PRENATAL COCAINE EXPOSURE IN THE RETINAL GANGLION-CELL LAYER OF THE RAT - A MORPHOMETRIC ANALYSIS

To study the effects of prenatal cocaine-exposure on the developing re tinal ganglion cell layer of the rat, female Wistar rats were administ ered subcutaneously (sc) cocaine hydrochloride (60 mg/kg body wt/d) or saline, or were not manipulated from gestational d 8-22. Male offspri ng were sacrificed at postnatal day 14 and 30. Radial semithin section s of epon-embedded flat mounts of the retinal quadrants were used to e valuate the following parameters along the centroperipheral axis: 1. T hickness of ganglion cell plus nerve fiber layer; 2. Nuclear size of g anglion cell layer neurons; and 3. Linear density (number per unit len gth) of ganglion cell layer neurons. To study the effects of cocaine a nd age on the retinal areas (temporal/nasal, dorsal/ventral), a repeat ed measures analysis of variance was used for each of the parameters m entioned above. All parameters were affected by prenatal exposure to c ocaine. The thickness of the ganglion cell plus nerve fiber layer was reduced in cocaine-exposed rats in comparison with the saline group. N uclear diameters were smaller in the cocaine than in the saline and co ntrol groups. The linear density was higher in the cocaine-exposed gro up than in the control and saline groups. The age-dependent decrease i n the linear density from postnatal day 14-30 was higher in the cocain e-exposed rats than in the saline group; the decrease in the linear de nsity along the centroperipheral axis found in both the control and sa line groups was not significant in the cocaine-treated group. These mo rphometric findings strongly support the view that prenatal cocaine-ex posure induces marked changes in the organization of the developing re tina.