Intracellular pH may be an important variable regulating neurotransmitter release. A number of pathological conditions, such as anoxia and ischemia, are known to influence intracellular pH, causing acidification of brain cells and excitotoxicity. We examined the effect of acidification on quantal glutamate release. Although acidification caused only modest changes in release, recovery from acid...

dry land salinity is one of the major problems affecting agricultural products. the main consequences of plant exposure to salt stress are water deficit and ion excess, which lead to several morphological and physiological changes. in order to evaluate the effect of salinity on some physiological characteristics of 8 spring rapeseed cultivars, an experiment was conducted in the greenhouse at ya...

We examined the effect of the glutamatergic agonist kainate on the membrane potential, the intracellular Na+ concentration ([Na+]i), the intracellular-free Ca2+ concentration, and on the intracellular pH of Retzius neurons of the medicinal leech, Hirudo medicinalis, in order to investigate the mechanism responsible for the intracellular acidification caused by glutamatergic stimulation. The rec...

Miura, Yoshikazu, and Hisao Matsui. Glucagon-like peptide-1 induces a cAMP-dependent increase of [Na ]i associated with insulin secretion in pancreatic islet -cells. Am J Physiol Endocrinol Metab 285: E1001–E1009, 2003; 10.1152/ajpendo.00005.2003.—Glucagon-like peptide-1 (GLP-1) elevates the intracellular free calcium concentration ([Ca2 ]i) and insulin secretion in a Na -dependent manner. To i...

Intermyofibrillar mitochondria were isolated from skeletal muscle (gastrocnemius) of cold-acclimated (4 degrees C) or control (30 degrees C) 4-wk-old ducklings. Ca2+ transport in the mitochondria was studied with the Ca2+-sensitive dye arsenazo III. The mitochondria actively took up Ca2+ but at a lower rate in mitochondria from cold-acclimated than from control ducklings. After addition of the ...

The cardiac sarcolemmal Na(+)-Ca2+ exchanger is modulated by intrinsic regulatory mechanisms. A large intracellular loop of the exchanger participates in the regulatory responses. We have proposed (Li, Z., D.A. Nicoll, A. Collins, D.W. Hilgemann, A.G. Filoteo, J.T. Penniston, J.N. Weiss, J.M. Tomich, and K.D. Philipson. 1991. J. Biol. Chem. 266:1014-1020) that a segment of the large intracellul...

We investigated the hypoxia-induced disturbance of cytosolic sodium concentration ([Na+]i) and of cytosolic calcium concentration ([Ca2+]i) in dopamine neurons of the substantia nigra pars compacta in rat midbrain slices, by combining whole cell patch-clamp recordings and microfluorometry. Transient hypoxia (3-5 min) induced an outward current (118.7 +/- 15.1 pA, mean +/- SE; VH = -60 mV). The ...

Mechanisms of energy deprivation contracture were investigated in cultured chick embryo ventricular cells. In the presence of zero-extracellular-Na+, (choline chloride substitution)-nominal-zero-Ca2+ [( Ca2+] approximately 5 microM), exposure of ventricular cells to 1 mM cyanide (CN) and 20 mM 2-deoxyglucose (2-DG)-zero-glucose solution resulted in the development of a contracture (video motion...

Myocardial infarction leads to compensatory ventricular remodeling. Disturbances in myocardial contractility depend on the active transport of Ca2+ and Na+, which are regulated by Na+-K+ ATPase. Inappropriate regulation of Na+-K+ ATPase activity leads to excessive loss of K+ and gain of Na+ by the cell. We determined the participation of Na+-K+ ATPase in ventricular performance early and late a...

A Na+/Ca2+ exchange mechanism has been recently described in human neutrophils that constitutes the principal pathway for Ca2+ influx into resting cells. The potential role of this system in regulating the respiratory burst in response to activation by the chemotactic tripeptide N-formyl-methionyl-leucyl-phenylalanine was explored. In the presence of 1 mM Ca2+, a variety of di- and trivalent ca...