The immunologic and chromatographic behavior of vasopressin-like immunoreactivity (VP-LI) extracted from rat brain tissue has been studied. VP-LI present in acid extracts of hypothalamic, hippocampal, and septal tissue was found to be immunologically identical to synthetic AVP. When extracts of hypothalamic tissue were fractionated using high-performance liquid chromatography, Arg8-vasopressin (AVP) was shown to be the predominant immunoreactive species. In contrast, in addition to AVP, extrahypothalamic brain tissue extracts also contained a small second vasopressin-immunoreactive peak. The effect of water deprivation on brain vasopressin content and chromatographic profile was also studied. This treatment depleted VP-LI content in the posterior pituitary but did not greatly alter that of hypothalamic or extrahypothalamic brain. Microdissection studies showed that VP-LI content was reduced, but only in a restricted number of extrahypothalamic brain nuclei, and that water deprivation failed to alter or increased content in other areas. The results suggest that VP-ergic neurons in the rat brain may be differentially activated.
- brain tissue
- water deprivation
ASJC Scopus subject areas
- Clinical Biochemistry
- Cellular and Molecular Neuroscience