The effect of ipsapirone on behavioural and cardiac responses in the shock-probe/defensive burying test in male rats.

The effects of the 5-HT1A receptor agonist, ipsapirone, on cardiac and behavioural responses of male Wistar rats in a conditioned defensive burying paradigm for anxiolytics were investigated. The shocked rats displayed defensive burying accompanied by an increase in heart rate. Ipsapirone-treated rats (5 and 10 mg/kg i.p.) showed less burying behaviour than did vehicle-treated controls, and the tachycardiac response was also reduced in a dose-dependent way whereas eating behaviour was facilitated. The results demonstrate the effectiveness of ipsapirone, thereby suggesting the involvement of 5-HT1A receptors in a conditioned anxiety situation that elicits an active coping behaviour and sympathetic activation.