EFFECT OF SALMON-CALCITONIN ON IN-VITRO OPIOID WITHDRAWAL

The effect on the in vitro withdrawal sign induced by naloxone in morp hine-dependent guinea pig ileum has been analyzed. Salmon calcitonin ( s-CT) dose-dependently reduced the force of the contraction induced by naloxone in morphine incubated tissues, but did not modify the contra ction induced by administration of acetylcholine or substance P in non -treated tissues. Therefore, the effect of s-CT in morphine incubated tissues may not be attributable to postsynaptic mechanisms, and an inh ibitory modulation of the excitatory pathways triggered by naloxone wo uld be suggested. In conclusion, s-CT is able to prevent the withdrawa l sign in vitro.