Effect of cadmium clonidine interaction in rats

Clonidine (5, 15, 50 micrograms/Kg i.v) caused dose dependent initial transient pressor response which was blocked by cadmium acetate (1 mg/Kg i.v) in dose dependent manner in anaesthetized rats. Cadmium acetate did not antagonize the pressor response of noradrenaline (4 micrograms i.v) which was blocked by Priscoline (10 mg/Kg i.v). Results of these experiments indicate that cadmium specifically blocks the initial transient pressor activity of clonidine. Cadmium is devoid of any adrenolytic activity. Cadmium clonidine interaction is independent of post synaptic adrenoceptor involvement.