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Morphine‐induced skin wheals: A possible model for the study of histamine release
Author(s) -
Saucedo Roberto,
Erill Sergio
Publication year - 1985
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1985.189
Subject(s) - morphine , histamine , astemizole , ed50 , pharmacology , (+) naloxone , opiate , medicine , chemistry , histamine h1 receptor , antagonist , anesthesia , receptor
We evaluated the ability of morphine to release histamine when injected intradermally in man. Mathematic analysis of the dose‐response (wheal) relationship suggested that two different effects were involved. The effect of low doses of morphine (0.05 to 1 µg) was clearly antagonized by naloxone (0.4 or 1.2 mg im 30 minutes before), whereas the effect of higher doses (5 to 50 µg) was not modified. The median effective doses of morphine (ED 50 ) for the low dose range effect were 0.07 ± 0.01 and 0.08 ± 0.01 µg before naloxone and 0.14 ± 0.02 and 0.15 ± 0.03 µg after 0.4 and 1.2 mg doses, respectively. Astemizole (45 mg po 30 minutes before) and oxatomide (60 mg po 120 minutes before) produced similar inhibition of histamine‐induced wheals, but there were clear differences in their effects on wheals elicited by morphine. Morphine ED 50 values for the low dose range effect rose from 0.09 ± 0.01 to 0.20 ± 0.01 µg after astemizole and from 0.08 ± 0.01 to 0.46 ± 0.04 µg after oxatomide. Opiate receptors may be involved in some of the effects produced by morphine injection in the human skin, but morphine‐induced wheals seem to offer a suitable model for the evaluation of agents capable of inhibiting histamine release in man. Clinical Pharmacology and Therapeutics (1985) 38 , 365–370; doi: 10.1038/clpt.1985.189