Volumetric and histochemical studies of the adrenal medulla of mouse after reserpine administration

The effect of single and consecutive doses of reserpine on the morphology and cellular and nuclear sizes of adrenaline and noradrenaline cells in the adrenals of mice were compared with the normal controls receiving saline injections as a placebo. Adopting micrometric measurements for apparent cellular and nuclear diameters, the pooled mean volumes of adrenaline- and noradrenaline-secreting cells and nuclei were calculated. Normal controls, subjected to consecutive daily saline injections for a period of 2 weeks, presented an increase in the intensity of the chromaffin reaction and higher values of cellular and nuclear sized of both cell types than those receiving single saline injection. These findings are believed to be a result of increased cell activity due to the stress of repeated, regular daily handling and injections. The increased measurements of cellular and nuclear sized of both types of adrenomedullary cells are believed to be due to hypermetabolic activity of the cells, thus exceeding action of reserpine shown by the decreased intensity of chromaffin reaction. Mice receiving daily consecutive reserpine injections showed a decrease in the intensity of chromaffin reaction as well as cellular and nuclear sizes compared with their controls. This is attributed to a decrease in the catecholamine content of the adrenal medulla.