Several studies indicate that opioids are involved in the control of consummatory sexual behavior in male Japanese quail. Naloxone has been reported to increase copulatory responses. In the current study, the effect of naloxone on appetitive sexual behaviors was assessed during extinction test trials. Naloxone was found to substantially reduce appetitive responding, suggesting that opioids differentially affect anticipatory and contact components of sexual behavior. (C) 2004 Elsevier B.V. All rights reserved.