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The effect of papaverine on acute opiate withdrawal in guinea pig ileum
Author(s) -
Capasso Anna,
Loizzo Alberto
Publication year - 2003
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.1234
Subject(s) - papaverine , agonist , (+) naloxone , pharmacology , chemistry , morphine , opioid , opiate , levorphanol , acetylcholine , endocrinology , medicine , receptor
In the present work the effect of papaverine, a non specic smooth muscle relaxant, was investigated on the naloxone‐precipitated withdrawal contracture of the acute morphine‐dependent guinea‐pig ileum in vitro . Furthermore, the effect of papaverine was also considered on DAGO (highly selective µ ‐agonist) and U50‐488H (highly selective k‐agonist) withdrawal to test whether the possible interaction of papaverine on opioid withdrawal involves µ ‐ and/or k‐opioid receptors. Following a 4 min in vitro exposure to opioid agonist, the guinea‐pig isolated ileum exhibited a strong contracture after the addition of naloxone. Papaverine treatment (1 × 10 −7 − 5 × 10 −7 − 1 × 10 −6 M) before or after the opioid agonists was able of both preventing and reversing the naloxone‐induced contracture after exposure to µ (morphine and DAGO) or k (U50‐488H) opiate agonists in a concentration‐dependent fascion. Both acetylcholine response and electrical stimulation were not affected by papaverine treatment whereas the nal opiate withdrawal was still reduced. The results of the present study indicate that papaverine was able to produce signicative inuence on the opiate withdrawal in vitro and papaverine was able to exert its effect both at µ and k opioid agonists. Copyright © 2003 John Wiley & Sons, Ltd.