Alpha-1-adrenergic receptors in the nucleus tractus solitarii region of rats with experimental and genetic hypertension.
The binding of the alpha 1-adrenergic receptors antagonist, 125I-HEAT, to membranes of nucleus tractus solitarii (NTS) regions of the brains of neurogenic hypertensive, spontaneously hypertensive (SH), and deoxycorticosterone (DOCA)/salt hypertensive rats and their respective controls was studied to quantitate the expression of alpha 1-adrenergic receptors. Scatchard analysis of the binding studies revealed a 1.8-fold increase in the Bmax of alpha 1-adrenergic receptors in NTS region membranes of SH rats when compared to their Wistar-Kyoto (WKY) control without significant difference in the Kd for 125I-HEAT. A decrease in the Kd with no difference in Bmax of receptors for 125I-HEAT was observed in the NTS region membranes of neurogenic hypertensive rats when compared with their sham-operated controls. In contrast, comparison of the Bmax and Kd values for 125I-HEAT binding in NTS region membrane of the DOCA/salt hypertensive rats and its sham-operated control showed no significant differences. We suggest that alterations in baroreceptor afferent activity may be related to alterations in central alpha 1-adrenergic receptors binding in SH rats and rats with neurogenic hypertension.
MacLean
M R
MR
Department of Physiology, University of Florida, College of Medicine, Gainesville 32610.
Phillips
M I
MI
Sumners
C
C
Raizada
M K
MK
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism; D000344:Afferent Pathways / Q000502:physiology; D000818:Animals; D001794:Blood Pressure; D002462:Cell Membrane / Q000378:metabolism; D003900:Desoxycorticosterone; D006973:Hypertension / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D008526:Medulla Oblongata / Q000378:metabolism*; D010627:Phenethylamines / Q000378:metabolism; D011311:Pressoreceptors / Q000502:physiology; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains; D011921:Rats, Inbred WKY; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D012016:Reference Values; D044024:Tetralones
D000317:Adrenergic alpha-Antagonists; D010627:Phenethylamines; D011942:Receptors, Adrenergic, alpha; D044024:Tetralones; C010652:BE 2254; D003900:Desoxycorticosterone