Effects of SR141716A on ethanol and sucrose self-administration

Previous studies have demonstrated that administration of central cannabinoid receptor (CB1) ligands can produce marked effects on ingestive behaviors. However, the possible relationship to ethanol self-administration has not been fully examined. The present series of experiments was designed to characterize further the role of CB1 receptors in appetitive and consummatory behaviors related to sucrose and ethanol.

To determine the relative contribution of CB1 receptors to ethanol seeking and consumption, a series of experiments was designed using the sipper-tube model. In this paradigm, the appetitive and consummatory phases of ethanol and sucrose self-administration are separated. In the appetitive phase, animals are required to complete a response requirement (16 lever presses) within 20 min. If the requirement is successfully completed, access to a sipper tube containing either sucrose or ethanol (consummatory phase) is made available for 20 min.

In the ethanol condition, the CB1 receptor antagonist SR141716A (0.3-3.0 mg/kg, ip) produced dose-related decreases in the probability of response requirement completion without significantly affecting latency to first lever press or overall lever press rate. In the sucrose condition, SR141716A (0.3-3.0 mg/kg, ip) increased first lever press latency without affecting lever press rate. In the consummatory phase, SR141716A (0.3-3.0 mg/kg, ip) administration markedly decreased total intake and the total number of licks for both ethanol and sucrose.

These data indicate that CB1 receptors are involved in mediating both appetitive and consummatory aspects of ingestive behaviors related to sucrose and ethanol.