Cyclic GMP alters Ca exchange in vascular smooth muscle

Conference · Tue Mar 04 23:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7189582

Magliola, L; Bailey, B; Jones, A W

Contraction and /sup 42/K efflux from vascular smooth muscle stimulated either by norepinephrine (NE) or by K-depolarization is dependent on an increase in cytosolic Ca concentration. The purpose of this study was to determine if cyclic GMP (cGMP) inhibited these processes and if inhibition was secondary to the action of cGMP on Ca movements. Basal cGMP content of rat aorta was 1.2 fmol/mg wet wt. Sodium nitroprusside (NP) increased cGMP approx.2-fold at 1 nM and approx.750-fold at 1 ..mu..M with no effect on cAMP levels. A 5 min pretreatment with NP (1 ..mu..M) completely prevented tension development induced by 3 ..mu..M NE. The same concentration of NP also inhibited NE-stimulated /sup 42/K and /sup 45/Ca efflux > 90 and > 80%, respectively. Removal of NP in the continued presence of NE (3 ..mu..M) caused recovery of the /sup 42/K efflux response to approx.75% of control with a half-time of approx.2.5 min. NP (1 ..mu..M) also caused a rapid relaxation of aorta contracted with 3 ..mu..M NE and a loss of the /sup 42/K efflux response with half-times of 2-3 min. In contrast, 100 ..mu..M NP produced only a 50% inhibition of contraction induced by high K (55 mM). Also, NP (1 ..mu..M) inhibited K-stimulated /sup 42/K efflux only approx.25%. These results demonstrate both a concentration- and a time-dependent relationship between increases in cGMP induced by NP and decreases in NE-stimulated contraction, /sup 42/K and /sup 45/Ca effluxes. They also indicate that the sensitivity of NE-induced contraction and /sup 42/K efflux to NP is greater than that induced by high K. These studies suggest that cGMP modulates the control sites for Ca exchange in the plasma membrane and sarcoplasmic reticulum.

• Research Organization: Univ. of Missouri Medical School, Columbia
• OSTI ID: 7189582
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ADRENAL HORMONES
ALKALI METAL ISOTOPES
ALKALI METALS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
AORTA
ARTERIES
AUTONOMIC NERVOUS SYSTEM AGENTS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD VESSELS
BODY
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR SYSTEM
CELL CONSTITUENTS
CELL MEMBRANES
CONTRACTION
DAYS LIVING RADIOISOTOPES
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELEMENTS
EVEN-ODD NUCLEI
GUANYLIC ACID
HORMONES
HOURS LIVING RADIOISOTOPES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANE TRANSPORT
MEMBRANES
METALS
MUSCLES
NEUROREGULATORS
NORADRENALINE
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PHYSIOLOGY
POTASSIUM
POTASSIUM 42
POTASSIUM ISOTOPES
RADIOISOTOPES
RATS
REACTION KINETICS
RODENTS
SARCOPLASMIC RETICULUM
STEROID HORMONES
SYMPATHOMIMETICS
TIME DEPENDENCE
TRACER TECHNIQUES
VERTEBRATES