Mechanisms of alpha-adrenergic regulation of the renal sodium/proton antiporter

Thesis/Dissertation · Fri Jan 01 04:00:00 EST 1988

OSTI ID:5641380

Gesek, F A

Some controversy exists concerning the relative roles of the {alpha}-adrenoceptor subtypes which mediate proximal tubular Na reabsorption. We hypothesized both {alpha}{sub 1} and {alpha}{sub 2} adrenoceptors may act to stimulate Na transport. We improved upon existing isolation techniques to obtain a highly enriched fraction of rat proximal tubule segments with which to test our hypothesis. Oxygen consumption measurements were first used to monitor alterations in transcellular transport stimulated by selective {alpha}{sub 1} and {alpha}{sub 2} adrenergic agonists and demonstrated both adrenoceptor subtypes increased transcellular Na transport. To examine if the enhancement of Na transport by {alpha}-adrenergic agonists were through a luminal Na//H exchange mechanism, the uptake of {sup 22}Na which was suppressible by the Na/H inhibitor, ethylisopropyl amiloride was utilized. The final sequence of experiments were designed to examine why {alpha}{sub 2} specific adrenoceptor agonists produced a range of stimulation extending from 22% with guanabenz to 98% with B-HT 933. After inhibition of a guanine nucleotide binding protein with pertussis toxin pretreatment, we were able to attenuate the {alpha}{sub 2} agonists responses. However, when a phorbol ester was used to stimulate Na/H exchange directly by activation of protein kinase C, the uptake of {sup 22}Na was inhibited by guanabenz.

• Research Organization: Wake Forest Univ., Winston-Salem, NC (USA)
• OSTI ID: 5641380
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
560300 -- Chemicals Metabolism & Toxicology
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ALKALI METAL ISOTOPES
ALKALI METALS
ANIMALS
ANTIGENS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-PLUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BODY
CARCINOGENS
CELL CONSTITUENTS
CELL MEMBRANES
DRUGS
ELEMENTS
ENZYMES
ESTERS
FUNCTIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KIDNEYS
LIGHT NUCLEI
MAMMALS
MATERIALS
MEMBRANE PROTEINS
MEMBRANE TRANSPORT
MEMBRANES
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHORBOL ESTERS
PHOSPHORUS-GROUP TRANSFERASES
PHOSPHOTRANSFERASES
PROTEINS
RADIOISOTOPES
RATS
RECEPTORS
RODENTS
SODIUM
SODIUM 22
SODIUM ISOTOPES
SYMPATHOMIMETICS
TOXIC MATERIALS
TOXINS
TRACER TECHNIQUES
TRANSFERASES
TUBULES
VERTEBRATES
YEARS LIVING RADIOISOTOPES