Research has indicated that gonadal hormones may mediate behavioral and biological responses to cocaine. Estrogen, in particular, has been shown to increase behavioral responding to cocaine in female rats relative to male rats. The current study investigated the effect of cocaine on locomotor activity and hormonal correlates in male and female Japanese quail (. Coturnix japonica). In Japanese quail, circulating hormone levels can be manipulated without surgical alterations via modifying the photoperiod. Male and female quail were housed on either 8L:16D (light:dark) or 16L:8D (light:dark) cycle for 21. days. Blood samples were taken prior to the beginning of the experiment and assays were performed to determine the levels of testosterone (T) and estradiol (E2). Quail were given injections of saline or cocaine (10 or 20. mg/kg) once a day for 10. days. Immediately after each injection, birds were placed in open field arenas and distance traveled was measured for 30. min. Results showed that male quail housed under long-light conditions exhibited cocaine-induced sensitization to 10. mg/kg cocaine which was correlated with the high levels of plasma T. Female quail housed under short-light conditions demonstrated sensitization to 10. mg/kg cocaine, but this was not correlated with the levels of plasma E2. The current findings suggest that cocaine-induced locomotor activity was associated with T in males but not with E2 in females.
|Number of pages||7|
|Journal||Hormones and Behavior|
|State||Published - Jan 1 2015|
Bibliographical noteFunding Information:
Financial support for this research was provided by the NIDA grant # DA022451 awarded to CKA. The authors would like to thank Luke Cornett, Joshua Shouse, Beth Ann Rice, B. Levi Bolin, Charlie Deese, and Aaron Barr for their help with data collection, animal care, and technical support. The authors would also like to thank Dr. Gregory F. Ball and his lab associates for their collaboration and guidance on this project.
© 2014 Elsevier Inc.
- Behavioral sensitization
- Distance traveled
- Japanese quail
- Locomotor activity
- Sex differences
ASJC Scopus subject areas
- Endocrine and Autonomic Systems
- Behavioral Neuroscience