Biomaterial Database

Effects of temperature and inorganic ions on calcium accumulation in microsomes from intestinal smooth muscle. 1975

L Hurwitz, and G Debbas, and S Little

Energy dependent calcium binding in microsomal vesicles from the longitudinal smooth muscle of the guinea pig intestine was investigated at two different temperatures (30 degrees C and 10 degrees C) and in the absence and presence of CdCl2, BaCl2 and MnCl2. The investigation was carried out to determine whether the effects of temperature and the effects of the divalent ions on microsomal calcium binding could be correlated with the effects of these interventions on the mechanical activity of the intact longitudinal fibers. A reduction in temperature from 30 degrees C to 10 degrees C inhibited both the uptake of calcium into the microsomes and the rate of release of calcium ions from the microsomes to the external medium. This exchange in temperature also slowed the rate of relaxation of the intact longitudinal muscle after it had been induced to contract with acetylcholine and subsequently allowed to relax by removing calcium ions from the bathing medium and adding 1 X 10(-3) M EGTA. The presence of CdCl2, like the reduction in temperature, decreased the uptake of calcium into the microsomal vesicles. However, the release of calcium from the microsomes was accelerated. BaCl2, produced the same effects as did CdCl2 on the uptake of calcium into microsomes but to a lesser extent. It had very little effect on the release of calcium ions from the microsomes. MnCl2 had no significant effects on either the uptake or release of calcium ions in the microsomal preparation. Both CdCl2 and MnCl2 exerted an inhibitory action on acetylcholine-induced contractile responses of the intact longitudinal fibers; whereas BaCl2 served to initiate a contractile response in the smooth muscle fibers. Thus, it would appear that the effects of a temperature change on microsomal calcium binding and on mechanical activity in intact fibers can be correlated; but the effects of CdCl2, BaCl2 and MnCl2 on these two cellular processes do not follow any consistent pattern.

UI	MeSH Term	Description	Entries
D007421	Intestine, Small	The portion of the GASTROINTESTINAL TRACT between the PYLORUS of the STOMACH and the ILEOCECAL VALVE of the LARGE INTESTINE. It is divisible into three portions: the DUODENUM, the JEJUNUM, and the ILEUM.	Small Intestine,Intestines, Small,Small Intestines
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008345	Manganese	A trace element with atomic symbol Mn, atomic number 25, and atomic weight 54.94. It is concentrated in cell mitochondria, mostly in the pituitary gland, liver, pancreas, kidney, and bone, influences the synthesis of mucopolysaccharides, stimulates hepatic synthesis of cholesterol and fatty acids, and is a cofactor in many enzymes, including arginase and alkaline phosphatase in the liver. (From AMA Drug Evaluations Annual 1992, p2035)
D008861	Microsomes	Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)	Microsome
D002104	Cadmium	An element with atomic symbol Cd, atomic number 48, and atomic weight 112.41. It is a metal and ingestion will lead to CADMIUM POISONING.
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D004533	Egtazic Acid	A chelating agent relatively more specific for calcium and less toxic than EDETIC ACID.	EGTA,Ethylene Glycol Tetraacetic Acid,EGATA,Egtazic Acid Disodium Salt,Egtazic Acid Potassium Salt,Egtazic Acid Sodium Salt,Ethylene Glycol Bis(2-aminoethyl ether)tetraacetic Acid,Ethylenebis(oxyethylenenitrile)tetraacetic Acid,GEDTA,Glycoletherdiamine-N,N,N',N'-tetraacetic Acid,Magnesium-EGTA,Tetrasodium EGTA,Acid, Egtazic,EGTA, Tetrasodium,Magnesium EGTA
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001464	Barium	An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.