Effect of leukotriene C4 on electromechanical activity and Ca/sup 2 +/ uptake in taenia coli
The actions of leukotriene C4 (LTC4) on electromechanical activity and /sup 45/Ca/sup 2 +/ uptake in guinea pig taenia coli were investigated. The contractile action of LTC4 was abolished by the removal of extracellular Ca/sup 2 +/. LTC4 concentrations eliciting a maximal contraction in normal medium produced no response in preparations depolarized with KCl. In single sucrose gap studies, LTC4 increased both the frequency of electrical spiking and tension. These effects were blocked by the dihydropyridine Ca/sup 2 +/-channel antagonist PY 108-068 and by the leukotriene receptor antagonist FPL 55712. In double sucrose gap experiments, LTC4 caused a small depolarization without measurable change in membrane conductivity; increased spontaneous electrical activity was again accompanied by an increase in tension. LTC4 caused a detectable increase in /sup 45/Ca/sup 2 +/ uptake only at extracellular Ca/sup 2 +/ concentrations less than 1 mM, and this was again inhibited by PY 108-068 or FPL 55712. It is concluded that the contractile effects of LTC4 in guinea pig taenia coli occur as a consequence of its ability to open voltage-sensitive Ca/sup 2 +/ channels, an effect that may occur independently of membrane depolarization.
- Research Organization:
- Univ. of Cambridge (England)
- OSTI ID:
- 6580599
- Journal Information:
- Am. J. Physiol.; (United States), Vol. 255
- Country of Publication:
- United States
- Language:
- English
Similar Records
Characterization of (/sup 3/H)leukotriene D4 binding sites in guinea-pig ventricular myocardium
Binding sites for /sup 3/H-LTC4 in membranes from guinea pig ileal longitudinal muscle
Related Subjects
ARACHIDONIC ACID
BIOCHEMICAL REACTION KINETICS
CALCIUM
MEMBRANE TRANSPORT
GUINEA PIGS
ELECTROPHYSIOLOGY
CALCIUM 45
CELL MEMBRANES
ELECTRIC CONDUCTIVITY
IN VITRO
TRACER TECHNIQUES
VASOCONSTRICTORS
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOXYLIC ACIDS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
DRUGS
ELECTRICAL PROPERTIES
ELEMENTS
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANES
METALS
MONOCARBOXYLIC ACIDS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
PHYSICAL PROPERTIES
PHYSIOLOGY
RADIOISOTOPES
REACTION KINETICS
RODENTS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques
550201 - Biochemistry- Tracer Techniques