Genetic and Salt-Related Alterations in Monoamine Neurotransmitters in Dahl Salt-Sensitive and Salt-Resistant Rats

Abstract

Monoamine and metabolite levels were determined in brain regions and in the kidney, heart and adrenals taken from Dahl salt-sensitive (DS) and salt-resistant (DR) rats on either normal (NS) or high (HS) (8.5% NaCl) salt diets. The HS diet significantly (p less than 0.01) elevated blood pressure only in DS rats. DS-HS rats had a significantly (p less than 0.001) greater increase in renal weight and a significantly (p less than 0.001) greater reductions in renal norepinephrine (NE) content and concentration than the DR-HS rats. Cardiac NE content and concentration were also lower (p less than 0.001) in DS rats when compared to DR rats. Adrenal catecholamines were also altered in DS rats. There were genetic differences in brain regional levels of NE, dopamine (DA) and serotonin (5-HT) between DR and DS rats. NE levels were significantly (p less than 0.03) higher in DS compared to DR rats in the pons and hypothalamus. DA levels were significantly (p less than 0.01) greater in the striatum of DS compared to DR rats as were 5-HT levels in the striatum and cortex. HS diets had no effect on brain monoamine or metabolite levels in either DS or DR rats except to elevate cortical 5-hydroxyindoleacetic acid levels. The cardiovascular implications of these genetic and salt-related changes in peripheral and central nervous system monoamines were discussed.