Cocaine adversely affects development of cortical embryonic neurons in vitro: immunocytochemical study of calcium-binding proteins.

Neurons of cerebral cortex from 15-16 day old embryos of white rats (Sprague-Dawley) were cultured in MEM enriched with 5% horse serum. On the 7th day after plating the cultures were divided into three experimental and one control groups (6-8 Petri dishes in each group). In group 1, cultures were grown without additives. In group 2, cocaine chloride was added at concentrations 0.3, 0.6 and 1 mg/ml of culture. In group 3, a monoclonal antibody against calcium-binding proteins, parvalbumin (APV) or calbindin (ACB) was added at a concentration 25 microl/ml. In group 4, a combination of cocaine +APV was added at a concentration 1 mg+25 microl/ml of culture media. On the 10th day cultures were immunostained using APV and ACB antibodies. In developing GABAergic neurons of group 2 cocaine produced cytotoxic effects that were expressed in drastic decrease in number of neurons and in degeneration of their processes. The lower concentrations of cocaine caused milder cytotoxity and their effects were reversible. The highest concentration of cocaine caused irreversible degeneration of neurons. Similar cytotoxity was caused by APV or ACB in group 3. The most severe cytotoxic effects were seen in group 4, where a mixture of cocaine and APV was used. Overall, it can be concluded that cocaine in higher concentrations directly affects development of GABAergic neurons in vitro.