Effects of ethanol dependence on chronic spinal rats monitored by spontaneous hind leg movements.

Physical dependence on ethanol was produced in rats whose spinal cords were transected at midthoracic level ("chronic spinal" rats) 2 months before chronic ethanol administration. Both intact and chronic spinal rats were treated with a light anesthetic dose of ethanol three times a day for 12 to 14 days and then abruptly withdrawn. All ethanol-treated animals exhibited severe withdrawal signs, including spontaneous withdrawal convulsions and death in over 60% of animals. In addition, ethanol-treated chronic spinal rats developed characteristic spontaneous hind leg movements (SLMs) during withdrawal. The time course, onset, peak and disappearance of these SLMs correlated well with other ethanol withdrawal signs. Cross dependence studies showed that ethanol, pentobarbital and barbital, diazepam and chlordiazepoxide, but not morphine, suppressed SLMs when drugs were administered at the peak intensity of SLM activities, while the intensity of behavioral withdrawal signs was also attenuated.