Biomaterial Database

A dual mechanism for intracellular pH regulation by leech neurones. 1985

W R Schlue, and R C Thomas

Neutral-carrier pH-sensitive micro-electrodes were used to investigate intracellular pH (pHi) in leech neurones. When used in snail neurones such electrodes gave very similar pHi values to those recorded simultaneously by recessed-tip glass micro-electrodes. Leech Retzius neurones superfused with a pH 7.4 HCO3--free physiological saline were found to have a pHi of 7.3, too high to be explained by a passive distribution of H+ or OH-. To investigate pHi regulation the pHi was decreased by one of three methods: by exposure to propionate, by adding and then removing NH4Cl or by exposure to CO2. Acidification by any method was followed by a recovery to normal pHi values within 15-20 min. In HCO3--free solutions, pHi recovery from acidification was blocked by removing external Na or by amiloride (2 mM). In solutions buffered with 2% CO2 and 11 mM-HCO3-, amiloride slowed but did not block pHi recovery. The anion exchange inhibitor SITS (4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulphonic acid) also slowed pHi recovery in the presence of HCO3-. In CO2/HCO3- solution the removal of external Na either slowed or blocked pHi recovery, and blocked it completely in the presence of amiloride. We conclude that in HCO3--free solutions pHi regulation is by a Na-H exchange system; but in the presence of HCO3- there is an additional mechanism which is probably a Na-dependent Cl-HCO3 exchanger.

UI	MeSH Term	Description	Entries
D007865	Leeches	Annelids of the class Hirudinea. Some species, the bloodsuckers, may become temporarily parasitic upon animals, including man. Medicinal leeches (HIRUDO MEDICINALIS) have been used therapeutically for drawing blood since ancient times.	Hirudinea,Hirudineas,Leeche
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D011422	Propionates	Derivatives of propionic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the carboxyethane structure.	Propanoate,Propanoic Acid,Propionate,Propanoates,Propanoic Acid Derivatives,Propanoic Acids,Propionic Acid Derivatives,Propionic Acids,Acid, Propanoic,Acids, Propanoic,Acids, Propionic,Derivatives, Propanoic Acid,Derivatives, Propionic Acid
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D006706	Homeostasis	The processes whereby the internal environment of an organism tends to remain balanced and stable.	Autoregulation
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
D000584	Amiloride	A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)	Amidal,Amiduret Trom,Amiloberag,Amiloride Hydrochloride,Amiloride Hydrochloride, Anhydrous,Kaluril,Midamor,Midoride,Modamide,Anhydrous Amiloride Hydrochloride,Hydrochloride, Amiloride,Hydrochloride, Anhydrous Amiloride,Trom, Amiduret
D000643	Ammonium Chloride	An acidifying agent that has expectorant and diuretic effects. Also used in etching and batteries and as a flux in electroplating.	Sal Ammoniac,Ammoniac, Sal,Chloride, Ammonium
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
D001639	Bicarbonates	Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.	Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid