Tyrosine hydroxylase immunoreactivity as indicator of sympathetic activity: simultaneous evaluation in different tissues of hypertensive rats

Katia Burgi,* Marina T. Cavalleri,* Adilson S. Alves, Luiz R. G. Britto, Vagner R. Antunes, and Lisete C. Michelini Am J Physiol Regul Integr Comp Physiol 300: R264–R271, 2011. December 9, 2010; doi:10.1152/ajpregu.00687.2009. Since tyrosine hydroxylase (TH) is a marker of sympathetic nerve activity, they wanted to investigate whether TH would be a good marker for sympathetic innervation to different organ beds. In this article they used tyrosine hydroxylase as an indicator of SNA. THir was then compared to NE content in arterioles by use of high-performance liquid chromatography (HPLC). They also recorded RSNA and LSNA in rats. They did all the recordings and sampling in SHRs and WKYs. They found that in the SHRs that the THir was increased in arterioles taken from heart and kidneys when compared to WKYs. The THir was not different between SHRs and WKYs. They then looked at NE by using HPLC. They found in the SHRs that there was increase NE in the kidney and heart when compared to the WKYs. They also measured RNSA and LSNA in SHRs and WKYs. They found that there were more spiking in the RSNA recording in SHRs when compared to WKYs. They saw no difference between groups for LSNA. This method may be useful for investigating regional difference SNA. -MD