Localization in Hypothalamus of Increased Incorporation of3H Cytidine into RNA in Response to Oral Hypertonic Saline12

Abstract

Autoradiography was performed on serial sections of the hypothalamus of mice given oral hypertonic saline using incorporation of ³H cytidine into RNA as an index of cellular activity. Of the 18 areas of the hypothalamus examined, increased activity in saline treated mice was found in 3 areas,: supraoptic nucleus, medial portion of arcuate nucleus, and ependymal cells lining the third ventricle adjacent to arcuate nucleus. The increased activity of the supraoptic nucleus is consistent with its known function of increased vasopressin synthesis in response to dehydration. The significance of the findings in the arcuate nucleus remains to be determined but this area may be involved in the reception and transmission the thirst stimulus or in a stress response. This method is presented as a non—invasive technique for localizing hypothalamic response to specific physiologic stimuli. (Endocrinology92: 1550, 1973)