This work was carried out on 42 albino rats to study the effect of the
C.C.B ( verapamil ) and H2 receptor antagonist ( ranitidine ) on marl ulation
of pain threshold and morphine antinociceptive action. Our study
demonstrated that C.C.B (verapamil) has antinociceptive action to thermal
stimulation indicating that ce is an important mediator in pain pathway.
However pretreatment of rats with a single Intraperitoneal dose (LP) of
C.C.B neither potentiates nor inhibited the analgesic activity of morphine.
On the other hand C.C.S (verapamil) decreased the antinociceptive action
of morphine when it was given in a single (LP) dose after morphine injection.
The H2 receptor antagonist (rantidine) induced antinociceptive activity
which may be through its binding to oplorP receptors as the opiate antagonist
naloxone blocked this effect. Pretreatment of rats with ranitidine
greatly potentiated the analgesic activity of morphine, a result which may
be of value in reducing the dose of morphine and hence its side effects |
