O. Sanmartinclark et al., CHANGES INDUCED BY SODIUM CROMOGLYCATE IN BRAIN CATECHOLAMINE TURNOVER IN MORPHINE-DEPENDENT AND ABSTINENT MICE, Psychopharmacology, 118(3), 1995, pp. 347-353
The effects of sodium cromoglycate (CRO) were studied in relation to t
he metabolism of brain catecholamines: dopamine (DA) and noradrenaline
(NA), and their metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), h
omovanillic acid (HVA) and 4-hydroxy-3-methoxyphenylethyleneglycol (MH
PG). CRO was injected SC in control mice, morphine-tolerant mice (tole
rance was induced by SC implantation of a 75 mg morphine pellet; CRO w
as administered on day 4 of addiction) and 30 min before abstinence (w
ithdrawal was induced by SC injection of naloxone (1 mg/kg) on day 4 o
f addiction). Brain catecholamines and their metabolites were measured
using high performance liquid chromatography coupled with electrochem
ical detection (HPLC-ECD), for DA, NA, DOPAC and HVA, and coupled with
fluorescence detection for MHPG. The ratios of DOPAC + HVA/DA and MHP
G/NA were kept as an index of DA and NA turnovers, respectively. CRO a
dministered 30 min before naloxone-precipitated withdrawal diminished
significantly NA levels in frontal cortex. CRO increased DA turnover i
n striatum and frontal cortex in naive animals and significantly dimin
ished DA levels in frontal cortex and DOPAC levels in frontal cortex a
nd midbrain in morphine-dependent mice. These findings are discussed i
n relation to the protective effects of CRO on opiate withdrawal and t
he effects of CRO on locomotor activity.