Rats were treated chronically with either cocaine (20 mg/kg/day, 14 days), morphine (incrementing doses of 10 mg/kg/day to 80 mg/kg, 11 days) or saline. During morphine or cocaine abstinence (48 h), dependent rats showed increased anxiety-like behavior in a conditioned defensive burying paradigm as evidenced by significantly shorter latencies to begin burying as well as a 4-fold increase in burying duration relative to salinetreated animals. This withdrawal-induced increase in burying behavior was blocked by pretreatment with either the β-adrenergic antagonist propranolol (5 mg/kg) or the lipophobic selective β1-antagonist, atenolol (5 mg/kg). These results are consistent with the possibility that activation of peripheral β1 receptors may substantially contribute to withdrawal-induced anxiety and that β-adrenergic antagonists could be useful in treating in cocaine and morphine dependent addicts.
All Science Journal Classification (ASJC) codes
- Beta-adrenergic antagonists
- Conditioned defensive burying
- Morphine dependence