Biomaterial Database

Modulation of force induced by pH in the guinea-pig uterus examined at two stages of the oestrous cycle. 1999

E K Naderali, and S Wray

Physiological Laboratory, University of Liverpool, UK.

Changes in pH have a marked influence on uterine contractility. Changes in uterine pH occur during pregnancy and labour, when marked endocrine changes are occurring. As hormonal status can also influence contractility, this study investigated whether pH-induced modulation of uterine force in influenced by hormonal changes. The effects of altering intracellular and extracellular pH on uterine contractions were studied in guinea-pigs on day 7 (high progesterone) and day 15 (low progesterone) of the oestrous cycle. Resting values of pH were significantly more acidic on day 15 compared with day 7, and more force was produced on day 15. Changing external pH produced similar changes in intracellular pH and force on both days. External acidification was associated with a large increase in force. In contrast, intracellular acidification, at constant external pH, reduced force. In conclusion, the stage of the oestrous cycle has a large effect on resting pH in the myometrium but only small effects on the pH-induced modulation of force, and the link between pH and force is complex.

UI	MeSH Term	Description	Entries
D007424	Intracellular Fluid	The fluid inside CELLS.	Fluid, Intracellular,Fluids, Intracellular,Intracellular Fluids
D009215	Myometrium	The smooth muscle coat of the uterus, which forms the main mass of the organ.	Uterine Muscle,Muscle, Uterine,Muscles, Uterine,Uterine Muscles
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011374	Progesterone	The major progestational steroid that is secreted primarily by the CORPUS LUTEUM and the PLACENTA. Progesterone acts on the UTERUS, the MAMMARY GLANDS and the BRAIN. It is required in EMBRYO IMPLANTATION; PREGNANCY maintenance, and the development of mammary tissue for MILK production. Progesterone, converted from PREGNENOLONE, also serves as an intermediate in the biosynthesis of GONADAL STEROID HORMONES and adrenal CORTICOSTEROIDS.	Pregnenedione,Progesterone, (13 alpha,17 alpha)-(+-)-Isomer,Progesterone, (17 alpha)-Isomer,Progesterone, (9 beta,10 alpha)-Isomer
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D004971	Estrus	The period in the ESTROUS CYCLE associated with maximum sexual receptivity and fertility in non-primate female mammals.
D005110	Extracellular Space	Interstitial space between cells, occupied by INTERSTITIAL FLUID as well as amorphous and fibrous substances. For organisms with a CELL WALL, the extracellular space includes everything outside of the CELL MEMBRANE including the PERIPLASM and the cell wall.	Intercellular Space,Extracellular Spaces,Intercellular Spaces,Space, Extracellular,Space, Intercellular,Spaces, Extracellular,Spaces, Intercellular
D005260	Female		Females
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
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations