[The relationship between the chromaffin granule number and the granule calcium content in the adrenal medulla of restrained rats].

Morphometry of numerical density and electron probe X-ray quantitative microanalysis were used to measure the alterations in the number and calcium content of chromaffin granules in adrenal medulla cells during emergency reaction of restrained rats. It was found that both the alterations showed monotonic decrease during the period of restraint, but the rate of decrease of the calcium content was significantly faster than that of the granules. These data are consistent with the hypothesis that calcium release from the granules may increase the cytoplasmic calcium concentration, which again triggers off the granule exocytosis.