A method for computer control of morphine ingestion by rats.

Area of Science:

• Pharmacology
• Animal Science
• Computer Science

Background:

• Accurate morphine administration is crucial for studying drug dependence.
• Traditional methods may not provide precise control over dosing and intake.
• Developing standardized methods for drug administration in research animals is essential.

Purpose of the Study:

• To describe a computer-controlled method for administering liquid diet and morphine to rats.
• To assess the induction of physical drug dependence in rats using this method.
• To compare the efficacy of this method with traditional drug administration techniques.

Main Methods:

• Sixteen rats received liquid diet and morphine via computer-controlled administration.
• Drug doses were individualized based on body weight and adjusted every 24 hours.
• Sensors monitored consumption to prevent overdistribution, with rats receiving either 103 mg/kg over 24 hr or 191 mg/kg over 48 hr.

Main Results:

• No weight loss or decreased fluid intake was observed during morphine administration.
• Following morphine withdrawal, significant body weight loss (6.1% and 8.3%) and decreased liquid diet intake (12.4 ml and 13.4 ml) occurred.
• This validated the induction of physical drug dependence.

Conclusions:

• Computer-aided administration allows for stepwise, small dose increments, leading to higher drug intake per unit time.
• This standardized method enables rats to ingest large morphine doses efficiently.
• The described method is advantageous for inducing physical drug dependence under controlled conditions.