Valproate reduces intake of alcoholic beverage among rats.

A series of experiments was carried out to assess the effects of valproate (VAL) on the intake of ethanol by rats. In Experiment 1, the effects of VAL (150 and 200 mg/kg, i.p.) were assessed across 10 days. Compared with controls, the 200 mg/kg dose reliably reduced intake of ethanol while also reliably increasing intake of water. The 150 mg/kg dose did not reliably reduce the intake of ethanol across the initial days, but it did across later days. Neither dose affected the total intake of fluids. Similarly, 5 days of oral dosing with VAL (400 and 600 mg/kg) reliably reduced the intake of ethanol without affecting the intake of water. However, body weights were reduced by the oral doses across the procedure. In another procedure, VAL (200 mg/kg, i.p.) produced a mild conditioned taste aversion to a saccharin solution, suggesting that VAL may reduce intake of ethanol because it produces a general malaise. However, this dose of VAL enhanced the intoxicating effects of ethanol (2.0 g/kg). Overall, the results are equivocal with respect to VAL as a potential medicine for treating alcohol misuse and alcoholism.

Isradipine blocks cocaine's ability to facilitate pressing for intracranial stimulation.

Using rats pressing for rewarding electrical intracranial stimulation of the medial forebrain bundle, it was found that a single administration of isradipine blocked the rate-enhancing effects of cocaine (5.0 mg/kg) at doses of 3.0 and 10.0 mg/kg. Also, when isradipine (3.0 mg/kg) was administered alone (without cocaine) for 5 consecutive days, pressing for intracranial stimulation was not reduced relative to placebo levels. In another experiment, isradipine (3.0 mg/kg) persistently blocked the rate-enhancing effects of cocaine (5.0 mg/kg) across 5 consecutive days. These results support the continued investigation of isradipine as a useful adjunct to other treatments for cocaine addiction.