ELEVATED TYROSINE-HYDROXYLASE MESSENGER-RNA LEVELS IN MEDULLA-OBLONGATA OF SPONTANEOUSLY HYPERTENSIVE RATS

The present study has investigated the expression of tyrosine hydroxyl ase (TH) mRNA and its activity in medulla oblongata of spontaneously h ypertensive rats (SHR) and Wistar Kyoto rats (WKY). The TH mRNA levels were determined by Northern blot and dot blot analyses. The TH activi ty and the expression of TH mRNA in medulla oblongata of SHR were sign ificantly higher than those of WKY. These results suggest that the hyp ertension of SHR may be related to the high activity of TH due to the high level of TH mRNA which increases norepinephrine levels in the med ulla oblongata.