Despite the increasing evidence of eye abnormalities, the effects of prenatal exposure to cocaine on the visual system are still poorly understood. This study was aimed at analyzing the qualitative and quantitative organization of the retinal photoreceptor cells (PR) and outer nuclear layer (ONL) after prenatal exposure to cocaine in the rat. Pregnant Wistar rats were given sc injections of cocaine hydrochloride (60 mg/kg body wt/d) or saline or were not manipulated; analyses were performed in the 14- and 30-d-old male offspring. Radial semithin and ultrathin sections of epon-embedded flat mounts of the retina showed displaced PR-like cells in the inner nuclear layer (INL), picnotic PR nuclei in INL, and ONL, and retinal PR rosettes and outer-segment debris in the subretinal space. The quantitative study showed an increased density of PR-like nuclei in the INL in PND14 cocaine-treated rats that were within normal values at PND30; no changes were detected in the PR mean nuclear diameter and in the packing density of PR nuclei in the ONL. These data constitute the first morphological demonstration of photoreceptor damage after prenatal cocaine-exposure probably owing to a direct action of the drug and/or to the cocaine-induced ischemia/hypoxia.

Aging↗

PubMedDate not supplied

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 retinal ganglion cell layer of the rat, female Wistar rats were administered subcutaneously (sc) cocaine hydrochloride (60 mg/kg body wt/d) or saline, or were not manipulated from gestational d 8-22. Male offspring were sacrificed at postnatal day 14 and 30. Radial semithin sections of epon-embedded flat mounts of the retinal quadrants were used to evaluate the following parameters along the centroperipheral axis: 1. Thickness of ganglion cells plus nerve fiber layer; 2. Nuclear size of ganglion cell layer neurons; and 3. Linear density (number per unit length) of ganglion cell layer neurons. To study the effects of cocaine and age on the retinal areas (temporal/nasal, dorsal/ventral), a repeated measures analysis of variance was used for each of the parameters mentioned above. All parameters were affected by prenatal exposure to cocaine. The thickness of the ganglion cell plus nerve fiber layer was reduced in cocaine-exposed rats in comparison with the saline group. Nuclear diameters were smaller in the cocaine than in the saline and control groups. The linear density was higher in the cocaine-exposed group than in the control and saline groups. The age-dependent decrease in the linear density from postnatal day 14-30 was higher in the cocaine-exposed rats than in the saline group; the decrease in the linear density along the centroperipheral axis found in both the control and saline groups was not significant in the cocaine-treated group. These morphometric findings strongly support the view that prenatal cocaine-exposure induces marked changes in the organization of the developing retina.

Aging↗

PubMedDate not supplied

Effects of prenatal cocaine exposure in the prefrontal cortex of the rat. A morphometric evaluation.

This work was undertaken in order to assess the organization of the prelimbic area of the medial prefrontal cortex of rats exposed prenatally to cocaine. Pregnant Wistar rats were assigned to the following groups: 1. Cocaine--60 mg/kg body wt/d sc, from gestational days 8-22; 2. Saline; 3. Pair-fed; and 4. Nonmanipulated. Male offspring were perfused on postnatal days 14 and 30. Six brains per group and per age were embedded in celloidin to calculate the volumes of the prelimbic area; sections from the other six brains were embedded in resin and processed for electron microscopy. Using semithin sections (2 microns) of layers II-III and V-VI, the following parameters were calculated: 1. The fraction of the neuropil occupied by neurons (VV); 2. The packing (NA) density; and 3. The numerical (NV) density. Qualitative alterations consisted of dispersed profiles of degenerated neurons and dendrites in the medial prefrontal cortex. No significant differences were found in the gross morphometric parameters when the cocaine group was compared with the other groups. A high interanimal variation was shown in the prelimbic volumes of postnatal day (PND) 14 cocaine-treated rats, and a a decrease in volumes was detected at PND30. Although there are some alterations in the main afferent cortical target area for dopaminergic input, its gross morphometric parameters do not seem to be sufficiently affected to account for the behavioral alterations referred to as being dependent on this brain region.

Aging↗