Sweets or cocaine? Male rats prefer sweets, female rats favor cocaine

The research was presented at Neuroscience 2010, the annual meeting of the Society for Neuroscience, held in San Diego.

"Human studies of cocaine dependence indicate that women enter drug treatment faster than men and report shorter cocaine-free periods," said lead author Kerry Kerstetter, of the University of California, Santa Barbara. "Given that male and female rats also exhibit differences in their responses to cocaine, we reasoned that they would exhibit differences when presented with a choice between food and the drug."

In the study, rats were trained to press one lever for food and a separate lever for cocaine; they were then offered a choice between the two. Female rats pressed the cocaine lever significantly more times than the male rats, while the male rats mainly selected the food. When higher doses of cocaine -- more than double -- were offered, both sexes chose cocaine more often, but female rats still preferred the drug more than the males.

"It appears that females are more likely than males to sacrifice food for low doses of cocaine," Kerstetter said.

Research was supported by the National Institute of Drug Abuse and by the National Alliance for Research on Schizophrenia and Affective Disorders Young Investigator Award to Tod E. Kippin.