Angiotensin and captopril increase alcohol intake

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Angiotensin II (ANG II) and angiotensin-converting enzyme (ACE) inhibitors are reported to reduce ethanol intake.
• ACE inhibitors are hypothesized to reduce ethanol intake by increasing central ANG II synthesis.
• Previous studies suggest a link between the renin-angiotensin system and alcohol consumption.

Purpose of the Study:

• To investigate the effects of ANG II and ACE inhibition on ethanol intake in rats.
• To test the hypothesis that centrally acting ANG II suppresses ethanol intake.
• To determine if ACE inhibitors reduce ethanol intake by increasing central ANG II.

Main Methods:

• Rats received continuous intraventricular infusions of ANG II for 7 days.
• Rats were administered oral or subcutaneous captopril (an ACE inhibitor) for up to 12 days.
• Ethanol intake was measured under various conditions of ANG II and ACE inhibition, including universal blockade of ACE in the brain and periphery.

Main Results:

• Continuous intraventricular ANG II infusions increased ethanol intake in rats.
• Low doses of oral or subcutaneous captopril also increased ethanol intake.
• A reduction in ethanol intake was observed only when ACE was universally blocked in both the brain and periphery, preventing ANG II mediation.

Conclusions:

• The results contradict the hypothesis that centrally synthesized or acting ANG II suppresses ethanol intake.
• Ethanol intake is not reduced by centrally acting ANG II.
• ACE inhibitors may reduce ethanol intake only when they act on both the central nervous system and the periphery.