CHANGES INDUCED BY SODIUM CROMOGLYCATE ON BRAIN-SEROTONIN TURNOVER INMORPHINE-DEPENDENT AND ABSTINENT MICE

This study was designed to explain the action of sodium cromoglycate ( CRO) on the brain serotonergic system in control, morphine tolerant (b y SC implantation of a 75 mg morphine pellet), and also in morphine de pendent mice just before naloxone-precipitated withdrawal. After SC in jections of CRO in control mice, morphine tolerant mice (day 4 of addi ction), and 1 h before abstinence (withdrawal was induced by SC inject ion of 1 mg/kg naloxone on day 4 of addiction), animals were decapitat ed and various brain areas were rapidly removed. 5HT (Serotonin) and 5 HIAA (5-hydroxyindole-3-acetic acid) were measured by high performance liquid chromatography coupled with electrochemical detection (HPLC-EC D). The ratio 5HIAA/5HT provided one index by which the turnover of th e indoleamine was measured. CRO increased the turnover of 5HT in most of the brain areas studied in both control and morphine dependent mice . Furthermore, previous administration of CRO prior to naloxone challe nge induced a significant increase in the 5HIAA/5HT ratio in the hypot halamus and striatum. These results are discussed as the reason for th e preventive effect of CRO on jumping behaviour in morphine abstinent mice.