Sabra rats as a model to differentiate between Na+ and GTP regulation of alpha 2-adrenoceptor densities.
Sodium ions and guanyl nucleotides play an important role in increasing alpha 2-adrenoceptor densities in cerebral and renal cortex of normotensive rats. The in vitro effect of Na+ and GTP was investigated on cerebral and renal alpha-adrenoceptors in hypertensive (SBH, salt-sensitive) and normotensive (SBN, salt-resistant) Sabra rats. In SBH and SBN rats, guanyl nucleotides increased cerebral and renal high-affinity alpha 2-adrenoceptor densities. Sodium ions, in contrast, markedly increased cerebral and renal high affinity alpha 2-adrenoceptor densities only in SBH rats. Under these conditions, alpha 1-adrenoceptor densities were unchanged. Thus, although Na+ and GTP both increase alpha 2-adrenoceptor densities, these agents appear to mediate their regulatory effects via different membrane components. Moreover, the absence of sodium regulation of alpha 2-adrenoceptors in SBN rats may be responsible for the resistance to salt-induced hypertension.
Parini
A
A
Diop
L
L
Dausse
J P
JP
Ben-Ishay
D
D
D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000502:physiology*; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000187:drug effects; D008954:Models, Biological; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D012964:Sodium / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D006160:Guanosine Triphosphate; D012964:Sodium; D011224:Prazosin