No Change in Rat Cerebral Cortex Calmodulin Content Following Chronic Treatment with Lithium, Reserpine, Imipramine, and Lithium Combined with Reserpine or Imipramine

Rats were treated 2-3 weeks with lithium, reserpine, imipramine, and combinations of lithium with reserpine or imipramine. Lithium was given in the diet, while the other drugs were dissolved in 0.9% saline and given intraperitoneally twice daily. The control and lithium groups received only vehicle injections. Twenty-four hours after the last injection the rats were decapitated and the cerebral cortex dissected. The tissue was sliced and the noradrenaline-stimulated cyclic AMP accumulation determined or the tissue was homogenized and centrifuged at 10,000 X g for 30 min. and the calmodulin content determined in the pellet and the supernatant. Reserpine treatment was found to cause an 50% increase in the noradrenaline-stimulated cyclic AMP accumulation, while treatment with imipramine and the combination lithium-imipramine decreased the noradrenaline-stimulated cyclic AMP accumulation by 40%. The tissue content of calmodulin was, however, found unaltered by all treatments.