Studies on a model of long term alcohol drinking.

This study investigated the effects of a dihydropyridine calcium channel antagonist in a free drinking model previously reported to show increased and 'uncontrolled' drinking. The results showed, rather than the previously reported increase in consumption, a gradual decrease in alcohol intake over 9-18 months. When the alcohol was withdrawn from one group of rats after 55 weeks free choice, the animals showed no behavioural signs of physical withdrawal, but they did demonstrate the expected elevated ethanol intake on reintroduction to ethanol after 2 weeks abstinence. A second group of rats were given 62 weeks free choice access to ethanol in groups of four, then transferred to single housing and baseline drinking levels established. Intraperitoneal injections of nimodipine 5 mg/kg, 20 mg/kg or Tween vehicle were then given once daily. Nimodipine had no effect on ethanol intake of animals with continuous access to ethanol, or of those animals withdrawn from ethanol and then reintroduced after 2 weeks of abstinence. However the unexpectedly low alcohol intake may have prevented any effects of nimodipine being seen.