In situ hybridization demonstrates vasopressin gene transcription in hypothalamic neurons of crossbred hypertensive × diabetes insipidus rats

In situ hybridization, Northern blotting, and solution hybridization assay were used to examine vasopressin-gene messenger ribonucleic acid (mRNA) transcripts in hypothalamic tissue from live strains of rats: Long Evans, Wistar Kyoto, and diabetes insipidus (Brattleboro) rats, spontaneously hypertensive stroke-prone rats, and cross-bred diabetes insipidus × spontaneously hypertensive strokeprone rats. A 290 base-pair, single-stranded RNA probe, with 221 bases complementary to exon (of the vasopressin gene was synthesized by the SP6 transcription vector system. This probe labeled appropriate neurohypophysial hypothalamic neurons, as well as suprachiasmatic nucleus cells, in tissue samples from all five strains of rats. Confirming other recent hybridization results with diabetes insipidus rat brain tissue, diabetic animals were found to transcribe their mutated vasopressin gene. In addition, this investigation found that the cross-bred diabetic hypertensive rat also synthesizes a vasopressin-gene messenger ribonucleic acid transcript. Quantitative analyses of solution and in situ hybridization results suggested the cross-bred diabetic hypertensive rat exhibits a level of vasopressin-gene messenger ribonucleic acid similar to diabetes insipidus rats. This observation is consistent with previous data on the cross-bred diabetic hypertensive rat which suggests they inherit the mutant vasopressin gene from Brattleboro rats.