scholarly journals The effect of electrical stimulation on the incorporation of l-[U-14C]valine into the protein of chopped tissue from guinea-pig cerebral cortex

1970 ◽  
Vol 118 (5) ◽  
pp. 791-800 ◽  
Author(s):  
C. T. Jones ◽  
P. Banks
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Guinea Pig ◽  
High Energy ◽  
Initial Increase ◽  
Nuclear Fraction ◽  
High Energy Phosphate ◽  
Experimental Conditions ◽  
Relative Contribution ◽  
Energy Dependent

1. Chopped tissue from guinea-pig cerebral cortex carried out an energy-dependent incorporation of [14C]valine into protein. 2. At all times studied the nuclear fraction of the homogenized tissue accounted for about 25% of the total labelled protein. 3. Electrical stimulation at first increased, but subsequently decreased, the rate of incorporation of [14C]valine into protein of the chopped tissue. 4. The initial increase in the incorporation of [14C]valine into protein occurred in the nuclear fraction. At later times electrical stimulation decreased the incorporation into all the subcellular fractions, but the relative contribution of the nuclear fraction to the total labelled protein increased. 5. These changes are discussed in relation to the changes in the rates of respiration, glycolysis, high-energy phosphate content and intracellular Na+ and K+ concentrations, which were measured under the same experimental conditions as those used to study protein synthesis.

scholarly journals The effect of electrical stimulation and ouabain on the uptake and efflux of l-[U-14C]valine in chopped tissue from guinea-pig cerebral cortex

1970 ◽  
Vol 118 (5) ◽  
pp. 801-810 ◽  
Author(s):  
C. T. Jones ◽  
P. Banks
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Guinea Pig ◽  
Kinetic Analysis ◽  
Creatine Phosphate ◽  
Complete Loss ◽  
Extracellular Concentration ◽  
Prolonged Stimulation ◽  
Energy Dependent

1. Chopped tissue from guinea-pig cerebral cortex carried out an energy-dependent accumulation of l-[14C]valine. 2. The uptake was dependent on the extracellular concentration of Na+ and was markedly inhibited by ouabain (20μm). The extent of the inhibition of uptake by ouabain was also Na+-dependent. 3. The accumulation of labelled valine was not directly dependent on the ATP and creatine phosphate contents of the slices. 4. Electrical stimulation increased the rate of [14C]valine uptake at first but ultimately led to a net loss of the label so that the amount of label present in the tissue was lower than in the controls. 5. The rate of loss of label during prolonged stimulation was dependent on the extracellular concentration of Na+. 6. The efflux of labelled valine from slices preloaded at 164mm-Na+ was studied at 164, 80 and 40mm-Na+ with and without electrical stimulation or ouabain. 7. Lowering the Na+ concentration or adding ouabain increased the rate of efflux. 8. Electrical stimulation had little effect on the rate of efflux at first but ultimately led to a more complete loss of label from the tissue than occurred in the control. A kinetic analysis of the efflux curves was attempted.

Implication of CO inactivation on myoglobin function

2006 ◽  
Vol 290 (6) ◽  
pp. C1616-C1624 ◽  
Author(s):  
Youngran Chung ◽  
Shih-Jwo Huang ◽  
Alan Glabe ◽  
Thomas Jue
Keyword(s):  
Heart Rate ◽  
Electrical Stimulation ◽  
Physiological Response ◽  
Consumption Rate ◽  
Contractile Function ◽  
High Energy ◽  
Facilitated Diffusion ◽  
High Energy Phosphate ◽  
H Nmr

Myoglobin (Mb) has a purported role in facilitating O2 diffusion in tissue, especially as cellular Po2 drops or the respiration demand increases. Inhibiting Mb with CO under conditions that accentuate the facilitated diffusion role should then elicit a significant physiological response. In one set of experiments, the perfused myocardium received buffer with decreasing Po2 (225, 129, and 64 mmHg). Intracellular Po2 declined, as reflected in the 1H NMR Val E11 signal of MbO2 (67%, 32%, and 18%). The addition of 6% CO further reduced the available MbO2 (11%, 9%, and 7%), as evidenced by the decline of the MbO2 Val E11 signal intensity at −2.76 ppm. In a second set of experiments, electrical stimulation increased the heart rate (300, 450, and 540 beats/min) and correspondingly the O2 consumption rate (MV̇o2). Intracellular Po2 also declined, as reflected in the slight drop in the MbO2 signal (100%, 96%, and 82%). MV̇o2 increased (100%, 114%, 165%). The addition of 3% CO in the stimulated hearts further decreased the available MbO2 (46%, 44%, and 29%). In all cases, CO inactivation of Mb does not induce any change in the respiration rate, contractile function, and high-energy phosphate levels. Moreover, the MbCO/MbO2 partition coefficient shifts dramatically from its in vitro value during hypoxia and increased work. The observation suggests a modulation of an intracellular O2 gradient. Overall, the experimental observations provide no evidence of a facilitated diffusion role for Mb in perfused myocardium and implicate a physiologically responsive intracellular O2 gradient.

XXV.—The Topography of the Cerebral Cortex of the Guinea-pig

1912 ◽  
Vol 31 ◽  
pp. 397-415 ◽  
Author(s):  
Williamina Abel
Keyword(s):  
Cerebral Cortex ◽  
Electrical Stimulation ◽  
Guinea Pig

This investigation was begun as a result of certain observations made by Dr T. Graham Brown, on reflexes in the guinea-pig (45). In various experiments he removed parts of the cerebral cortex and found that little if any disturbance, either motor or sensory, ensued. It was thereupon suggested that an examination should be made of the cortex histologically and by electrical stimulation in order to locate the position of the various areas.

Nuclear Fos immunoreactivity in guinea pig myenteric neurons following activation of motor activity

1997 ◽  
Vol 273 (2) ◽  
pp. G498-G507 ◽  
Author(s):  
R. C. Ritter ◽  
M. Costa ◽  
S. H. Brookes
Keyword(s):  
Electrical Stimulation ◽  
Guinea Pig ◽  
Motor Activity ◽  
Muscle Tone ◽  
Smooth Muscle Contraction ◽  
Early Gene ◽  
Enteric Neurons ◽  
Experimental Conditions ◽  
Fos Expression

To identify enteric neurons activated during intestinal motor activity, we examined myenteric plexus of guinea pig small intestinal segments for expression of the immediate early gene product, Fos. Fos immunoreactivity was detected immunohistochemically following in vitro manipulations, which included distension, electrical stimulation, exposure to forskolin, and peristalsis. All of these manipulations induced neuronal Fos expression, which was prevented by tetrodotoxin, indicating that expression depended on nerve activity. Distension-induced Fos expression was blocked by omega-conotoxin and significantly reduced by hexamethonium, indicating that neurons expressing Fos immunoreactivity were activated synaptically. Blocking smooth muscle contraction with nicardipine reduced expression of neuronal Fos, suggesting that muscle tone influences neuronal activity. Calbindin-immunoreactive putative sensory neurons did not express Fos during distension, peristalsis, or exposure to forskolin and expressed Fos only weakly after strong electrical stimulation. Conversely, calretinin-immunoreactive ascending excitatory interneurons and longitudinal muscle motoneurons exhibited Fos immunoreactivity after all experimental manipulations. These results indicate that Fos expression can, with some caution, be used to identify classes of enteric neurons activated by different stimuli under various experimental conditions.

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