As part of efforts to understand drug abuse, Georgia State University researchers are finding that adolescent rats appear to be less vulnerable to the long-term effects of withdrawal and relapse in certain types of drug use than rats that take the drugs in adulthood.
The laboratory of Kyle Frantz, associate professor of neuroscience, studied reinstatement of drug seeking in adolescent and adult rats which were given morphine, heroin, and cocaine. Surprisingly, the younger animals were less motivated to seek the drugs after a period of abstinence than the older ones were. The younger rats also showed fewer signs of drug withdrawal.
"The model is important, and the results are interesting because they suggest that younger animals do not show the same level of vulnerability as adults, at least with the drugs and conditions we've tested so far," said Frantz, whose graduate students, James Doherty and Chen Li, and technician Bonnie Williams, conducted the research with help from outstanding GSU undergraduates.
Rats were first given drugs to induce urges to take more of the drug. Rats then pressed levers to receive more drugs, while receiving visual cues like lights and sound. After receiving drugs and then being withdrawn from them, researchers used the cues to see if the rats would reinstate drug-seeking behavior. Researchers found that younger rats were less likely to seek the drugs compared to the adult rats, regardless of which drug they had taken previously.
By better understanding this animal model of drug intake and relapse, scientists have an opportunity to learn how the process works in humans, and may be able to apply the knowledge gained to develop better treatments.