Apomorphine-induced Acute Withdrawal in Rats.
Institution
Morehead State University
Faculty Advisor/ Mentor
Wesley White
Abstract
Moderate doses of amphetamine (AMPH) produce an immediate stimulant state (during the first several hours post-drug and indicated by excessive locomotion) and an acute withdrawal (around hour 20 post-drug and reflected in hypoactivity), followed by a recovery (beginning around hour 24 post-drug and reflected in a normalization of activity). The purpose of the study was to determine whether the selective dopamine agonist apomorphine (APO) could mimic these changes in activity. Adult male Wistar rats were treated four times at 96-hour intervals: Two control treatments were followed by two drug treatments. Two hours before each treatment, animals were placed in individual open fields (45 cm square), where activity was quantified, with arrays of infrared detectors, for 33 hours following each treatment. While in the open fields, animals were on a 12-12 hour light-dark cycle and had free access to food and water. For drug treatments, different groups of rats received AMPH (2.0 mg/kg, sc) or APO (1.0 or 2.0 mg/kg, sc). All treatments occurred at lights on. APO, like AMPH, produced both hyperactivity immediately post-drug and hypoactivity around hour 20 post-drug, followed by normalization of activity beginning around hour 24 post-drug. Dopaminergic systems appear to be involved in acute withdrawal and recovery from AMPH administration.
Apomorphine-induced Acute Withdrawal in Rats.
Moderate doses of amphetamine (AMPH) produce an immediate stimulant state (during the first several hours post-drug and indicated by excessive locomotion) and an acute withdrawal (around hour 20 post-drug and reflected in hypoactivity), followed by a recovery (beginning around hour 24 post-drug and reflected in a normalization of activity). The purpose of the study was to determine whether the selective dopamine agonist apomorphine (APO) could mimic these changes in activity. Adult male Wistar rats were treated four times at 96-hour intervals: Two control treatments were followed by two drug treatments. Two hours before each treatment, animals were placed in individual open fields (45 cm square), where activity was quantified, with arrays of infrared detectors, for 33 hours following each treatment. While in the open fields, animals were on a 12-12 hour light-dark cycle and had free access to food and water. For drug treatments, different groups of rats received AMPH (2.0 mg/kg, sc) or APO (1.0 or 2.0 mg/kg, sc). All treatments occurred at lights on. APO, like AMPH, produced both hyperactivity immediately post-drug and hypoactivity around hour 20 post-drug, followed by normalization of activity beginning around hour 24 post-drug. Dopaminergic systems appear to be involved in acute withdrawal and recovery from AMPH administration.