Subcutaneous silastic implants: maintenance of high blood ethanol levels in rats drinking a liquid diet.

A new subcutaneous form of ethanol exposure in rats is described. The Sustained Ethanol Release Tube (SERT) for rats is similar to an earlier device reported for mice, except that only one refill per day is required. This device, plus an intragastric loading dose for initially raising blood ethanol levels (BEL), is capable of maintaining high BEL for greater than 12 hours. Supplementation of SERT-released ethanol with a Sustacal chocolate-flavored diet with 37% of total energy as ethanol produces high, stable BEL for indefinite periods. Maintenance of such BEL for 9 days is sufficient to cause dramatic withdrawal signs when ethanol exposure is stopped. The method is useful as a model for conveniently and quickly producing physical dependence to ethanol in rats.