Histamine release from rat mast cells induced by the metabolic activation of drugs of abuse into free radicals.
BACKGROUND
The metabolic activation of morphine, cocaine and methadone into free radicals could have pathophysiological relevance in the organic injuries of drug addiction.


METHODS
Isolated purified rat serosal mast cells were incubated with morphine, cocaine and methadone (10(-7) M-10(-4) M) with oxidative enzymes (prostaglandin-H-synthetase, 25 mU; rat liver homogenate fraction S 10-mix, 400 microl), and with the drugs of abuse in the presence of oxidative enzymes. Histamine and lactate dehydrogenase (LDH) were analysed with a fluorimetric and spectrophotometric assay, respectively; the generation of malonyldialdehyde (MDA) was measured by a spectrophotometric assay.


RESULTS
The release of mast cell histamine and the generation of MDA are present only when mast cells were incubated with the drugs of abuse in the presence of oxidative enzymes. This release was dependent on the concentration of the drug in question and showed a maximum value at 10(-4) M. Moreover, in parallel experiments we demonstrated that, under the same experimental conditions, the release of LDH was always less than 20% of the total, suggesting that this effect is due to a selective exocytotic process. Histamine release and MDA generation were abated by the free radical scavengers: reduced glutathione, 10(-4) M GSH and alpha-tocopherol, 10(-4) M and by the spin trapper 5.5-dimethyl-1-pyrroline-N-oxide, 10(-4) M DMPO. The light and electron microscopic features are consistent with exocytotic secretion in the cases of morphine and methadone and with cell lysis in the case of cocaine.


CONCLUSIONS
These results suggest that morphine, cocaine and methadone are activated into free radicals which produce membrane lipid perturbation and histamine release, suggesting that a massive release of mast cell histamine could be an additional risk factor in heroin and cocaine overdoses.
Di Bello
M G
MG
Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
Masini
E
E
Ioannides
C
C
Ndisang
J F
JF
Fomusi Ndisang
J
J
Raspanti
S
S
Bani Sacchi
T
T
Mannaioni
P F
PF
D000818:Animals; D001711:Biotransformation; D002469:Cell Separation; D003042:Cocaine / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005609:Free Radicals / Q000378:metabolism; D006636:Histamine Release / Q000187:drug effects*; D013287:Illicit Drugs / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D008315:Malondialdehyde / Q000032:analysis; D008407:Mast Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008691:Methadone / Q000378:metabolism; D008862:Microsomes, Liver / Q000201:enzymology; D009020:Morphine / Q000378:metabolism; D009294:Narcotics / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar
D018765:Dopamine Uptake Inhibitors; D016166:Free Radical Scavengers; D005609:Free Radicals; D013287:Illicit Drugs; D009294:Narcotics; D008315:Malondialdehyde; D009020:Morphine; D007770:L-Lactate Dehydrogenase; D011451:Prostaglandin-Endoperoxide Synthases; D003042:Cocaine; D008691:Methadone