This work was carried out on 42 albino rats to study the effect of the C.C.B (verapamil) and 1-12 receptor antagonist (ranilidute) on modula¬tion of pain threshold and morphine antinociceptire action. Our study demonstrated that C.C.B (verapamil) has antinociceptive action to thermal stimulation indicating that Ca+ is an important mediator in pain pathway. However pretreatment of rats with a single Jutraperitoneal dose (f.p) of C.C.B neither potentiates nor inhibited the analgesic activity of morphine. On the other hand C.C.B (veraparnil) decreased the antinociceptive action of morphine when it was given in a single (EP) dose after morphine injec¬tion. The 1-I2 receptor antagonist (rantidine) induced ardinociceptive activi¬ty which may be through its binding to opiate receptors as the opiate an¬tagonist 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.