Barbiturate dependence in mice: evidence for beta-adrenergic receptor proliferation in brain.

C57BL/6J and DBA/2J inbred mice were assayed for beta-adrenergic receptor density following seven days of chronic phenobarbital intoxication. These physically dependent mice showed a greater brain receptor density than did the control, while acute intoxication to phenobarbital produced no significant effects. C57BL/6J mice showed a higher average receptor density than did the DBA/2J mice under all conditions. These findings support the hypothesis that chronic barbiturate intoxication leads to a receptor supersensitivity which may play a role in the phenomena of functional tolerance and physical dependence.