Role of. alpha. sub 2 -adrenergic receptors in the carotid body response to hypoxia
- Case Western Univ., Cleveland, OH (United States)
Clonidine, which acts in part as an {alpha}{sub 2}-adrenergic receptor agonist, depresses ventilation. The authors examined the role of {alpha}{sub 2}-receptors in carotid chemoreceptor activity. The density of {alpha}{sub 2}-receptors was determined in membrane fractions of 18 cat carotid bodies using {sup 125}I-iodoclonidine with 0.1 mM epinephrine or 10 {mu}M SKF-86466 defining nonspecific binding. {alpha}{sub 2}-Adrenergic receptor density averaged 0.6{plus minus}0.1 fmol/carotid body (mean {plus minus} SEM) and was comparable to other sympathetic target tissues. The authors then studied the effects of an agonist (guanabenz) and an antagonist (SKF-86466; 6-Cl-N-methyl-2,3,4,5-tetrahydro-1-H3-benzazepine) specific for {alpha}{sub 2}-receptors on baseline and hypoxia-stimulated carotid body discharge, in 10 anesthetized, paralyzed and artificially ventilated cats. Intracarotid infusion of guanabenz for 5 minutes caused a dose-dependent depression of the baseline activity and reduced the chemoreceptor response to hypoxia by 88.0{plus minus}5.8% of the vehicle-injected controls. Intravenous administration of SKF-86466 reversed the effects of guanabenz on the carotid body activity. in contrast, chemoreceptor depression caused by dopamine was unaffected by SKF-86466. SKF-86466 alone increased baseline discharge and potentiated the chemoreceptor response to hypoxia by 34.0 {plus minus} 9.6% of the controls. These results demonstrate that {alpha}{sub 2}-adrenergic receptors are present in the cat carotid body and they exert an inhibitory influence on the chemoreceptor response to hypoxia.
- OSTI ID:
- 6061702
- Report Number(s):
- CONF-9104107-; CODEN: FAJOE
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Vol. 4:3; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
Similar Records
Photoaffinity labeling of human platelet and rabbit kidney. cap alpha. -adrenoceptors with (/sup 3/H)SKF 102229
Dopamine D1 receptors of the calf parathyroid gland: Identification of a ligand binding subunit with lower apparent molecular weight but similar primary structure to neuronal D1 receptors
Related Subjects
SYMPATHOLYTICS
BIOCHEMICAL REACTION KINETICS
ANOXIA
CATS
IODINE 125
IODINE COMPOUNDS
NERVE TISSUE
RECEPTORS
RESPIRATION
SYMPATHOMIMETICS
TRACER TECHNIQUES
ANIMAL TISSUES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BODY
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRON CAPTURE RADIOISOTOPES
HALOGEN COMPOUNDS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE PROTEINS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PROTEINS
RADIOISOTOPES
REACTION KINETICS
TISSUES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques