Comparison of ?-endorphin immunoreactivity in hypothalamic and brainstem nuclei of normotensive and age-matched hypertensive rat strains.
The concentration of ?-endorphin immunoreactivity was determined in 21 hypothalamic and brainstem nuclei of Sprague-Dawley (SD) and 6 and 14 week Wistar-Kyoto (WKY) and Spontaneously Hypertensive (SH) rats. The concentrations of ?-endorphin immunoreactivity were greater in the hypothalamic nuclei than in the brainstem nuclei approximately by a factor of 5. A significant strain-age interaction was observed in the ?-endorphin immunoreactivity levels in the anterior hypothalamic area, paragigantocellular reticular nucleus and locus coeruleus of age-matched SH and WKY rats in that immunoreactivity levels fell in the age period studied (6-14 weeks) in WKY rats and rose in SH rats. These biochemical differences are related in time to a growth period during which there are large increases in blood pressure in the SH rat and may thus have a pathogenetic significance.
Conway
E L
EL
University of Melbourne, Clinical Pharmacology and Therapeutics Unit, Department of Medicine, Austin Hospital, Heidelberg, 3084, Australia.
Maccarrone
C
C
Jarrott
B
B
Louis
W J
WJ