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

Journal Article · · Journal of Cardiovascular Pharmacology; (United States)
OSTI ID:5272249
; ; ; ; ;  [1]
  1. Univ. of Utah School of Medicine, Salt Lake City (USA)
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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), Journal Name: Journal of Cardiovascular Pharmacology; (United States) Vol. 17:4; ISSN 0160-2246; ISSN JCPCD
Country of Publication:
United States
Language:
English

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Related Subjects

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