Mr 40,000 and Mr 39,000 pertussis toxin substrates are increased in surgically denervated dog ventricular myocardium

Journal Article · Mon Apr 01 00:00:00 EST 1991 · Journal of Cardiovascular Pharmacology; (United States)

OSTI ID:5272249

Hershberger, R E; Feldman, A M; Anderson, F L; Kimball, J A; Wynn, J R; Bristow, M R ^[1]

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1. Univ. of Utah School of Medicine, Salt Lake City (USA)

To test the general hypothesis that cardiac innervation may participate in myocardial G protein regulation, we examined the effects of complete intrapericardial surgical denervation or sham operation in dogs. In particulate fractions of dog left ventricular (LV) myocardium harvested 28-33 days after denervation or sham operation, Mr 40,000 and Mr 39,000 pertussis toxin-sensitive substrates (G proteins) were increased by 31% (1.31 +/- 0.084 vs 1.00 +/- 0.058 OD, arbitrary units, p less than 0.01) and 40% (1.40 +/- 0.117 vs. 1.000 +/- 0.084 OD, arbitrary units, p less than 0.02), respectively, as compared with sham-operated controls. The Mr 40,000 pertussis toxin-sensitive band comigrated with a pertussis toxin-sensitive substrate in human erythrocyte membranes known to contain an alpha Gi species. In these same preparations basal, GTP and GppNHp stimulated adenylate cyclase activities were decreased in denervated heart by 20, 26, and 19%, respectively, consistent with increased activity of an inhibitory G protein. In contrast, Gs function was not altered, because cyc(-) membranes reconstituted with membrane extracts and fluoride and beta-receptor-stimulated adenylate cyclase activity were not different between groups. Furthermore, adenylate cyclase catalytic subunit function as assessed with forskolin and manganese stimulation was not different between preparations of control and denervated heart. We conclude that in preparations of surgically denervated dog myocardium Mr 40,000 and Mr 39,000 pertussis toxin-sensitive G proteins are increased by 31 and 40%, respectively, and that functional alterations in adenylate cyclase activity exist, consistent with increased inhibitory G-protein function.

• OSTI ID: 5272249
• Journal Information: Journal of Cardiovascular Pharmacology; (United States), Vol. 17:4; ISSN 0160-2246
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CYCLASES
ENZYME ACTIVITY
MYOCARDIUM
BIOCHEMISTRY
PROTEINS
BIOSYNTHESIS
CATECHOLAMINES
CELL MEMBRANES
DOGS
ERYTHROCYTES
FLUORIDES
HEART
IN VITRO
INHIBITION
MAN
MANGANESE
NERVE CELLS
PHOSPHORUS ISOTOPES
TRACER TECHNIQUES
AMINES
ANIMAL CELLS
ANIMALS
AROMATICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CHEMISTRY
ELEMENTS
ENZYMES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
LYASES
MAMMALS
MATERIALS
MEMBRANES
METALS
MUSCLES
ORGANIC COMPOUNDS
ORGANS
PHENOLS
POLYPHENOLS
PRIMATES
SOMATIC CELLS
SYNTHESIS
TRANSITION ELEMENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques