scholarly journals On the length of the internodes in the sciatic nerve of Rana temporaria (Fusca) and Rana Pipiens: Being a re-examination by biometric methods of the data studied by boycott ('04) and takahashi ('08)

1910 ◽  
Vol 20 (1) ◽  
pp. 19-47 ◽  
Author(s):  
Shinkishi Hatai
Keyword(s):  
Sciatic Nerve ◽  
Rana Pipiens ◽  
Rana Temporaria

scholarly journals ACTION OF POTASSIUM AND NARCOTICS ON RECTIFICATION IN NERVE AND MUSCLE

1944 ◽  
Vol 28 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Rita Guttman
Keyword(s):  
Plasma Membrane ◽  
Sciatic Nerve ◽  
Rana Pipiens ◽  
Current Flow ◽  
Barium Chloride ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Potassium Ions ◽  
Excess Calcium ◽  
Simultaneous Decrease

Electrical rectification was demonstrated in whole sartorius muscle and sciatic nerve of Rana pipiens and also in the single giant nerve fiber of the northern squid, Ommastrephes illecibrossus. It is probably a property of the plasma membrane. Rectification decreases reversibly under the influence of increased concentrations of the potassium ion and with chloroform, veratrine sulfate and isoamyl carbamate. No effect was found with lack of calcium, excess calcium, or barium chloride. Decrease in rectification is invariably accompanied by simultaneous decrease in resting potential. A proposed explanation of the mechanism of rectification is discussed. Rectification in a living membrane, viz. a change in resistance with change in direction of current flow, may possibly be explained in terms of a change in the concentration of potassium ions in the membrane.

scholarly journals Reduction of calcium inactivation of sarcoplasmic reticulum calcium release by fura-2 in voltage-clamped cut twitch fibers from frog muscle.

1993 ◽  
Vol 102 (2) ◽  
pp. 333-370 ◽  
Author(s):  
D S Jong ◽  
P C Pape ◽  
W K Chandler ◽  
S M Baylor
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Rana Pipiens ◽  
Calcium Release ◽  
Single Channel ◽  
Rana Temporaria ◽  
Fixed Number ◽  
Optical Recording ◽  
Fura 2 ◽  
Peak Rate ◽  
Steady Level

Cut fibers from Rana temporaria and Rana pipiens (striation spacing, 3.9-4.2 microns) were mounted in a double Vaseline-gap chamber and studied at 14 degrees C. The Ca indicator purpurate-3,3' diacetic acid (PDAA) was introduced into the end pools and allowed to diffuse into the optical recording site. When the concentration at the site exceeded 2 mM, step depolarizations to 10 mV were applied and the [Ca] transient measured with PDAA was used to estimate Ca release from the sarcoplasmic reticulum (SR) (Baylor, S. M., W. K. Chandler, and M. W. Marshall. 1983. Journal of Physiology. 344:625-666). With depolarization, the rate of SR Ca release increased to an early peak and then rapidly decreased several-fold to a quasi-steady level. The total amount of Ca released from the SR at the time of peak rate of release appeared to be independent of SR Ca content, consistent with the idea that a single activated channel might pass, on average, a fixed number of ions, independent of the magnitude of the single channel flux. A possible explanation of this property is given in terms of locally induced Ca inactivation of Ca release. The solution in the end pools was then changed to one with PDAA plus fura-2. SR Ca release was estimated from the [Ca] transient, as before, and from the delta [Cafura-2] signal. On average, 2-3 mM fura-2 increased the quasi-steady level of the rate of SR Ca release by factors of 6.6 and 3.8, respectively, in three fibers from Rana temporaria and three fibers from Rana pipiens. The peak rate of release was increased in five of the six fibers but to a lesser extent than the quasi-steady level. In all fibers, the amplitude of the free [Ca] transient was markedly reduced. These increases in the rate of SR Ca release are consistent with the idea that Ca inactivation of Ca release develops during a step depolarization to 10 mV and that 2-3 mM fura-2 is able to reduce this inactivation by complexing Ca and thereby reducing free [Ca]. Once the concentration of fura-2 becomes sufficiently large, a further increase reduces the rate of SR Ca release. On average, 5-6 mM fura-2 increased the quasi-steady rate of release, compared with 0 mM fura-2, by 6.5 and 2.9, respectively, in four fibers from Rana temporaria and three from Rana pipiens.(ABSTRACT TRUNCATED AT 400 WORDS)

The roof of the hindbrain in Rana pipiens and Rana temporaria

1980 ◽  
Vol 184 (2) ◽  
pp. 506-510 ◽  
Author(s):  
G.S. Dolman ◽  
Gordon Brocklehurst
Keyword(s):  
Rana Pipiens ◽  
Rana Temporaria

Observations on the origin of the ‘germinal cytoplasm’ in Xenopus laevis

Development ◽  
1969 ◽  
Vol 22 (2) ◽  
pp. 229-251
Author(s):  
Renata Czołowska
Keyword(s):  
Xenopus Laevis ◽  
Germ Cells ◽  
Rana Pipiens ◽  
Rana Temporaria ◽  
Primordial Germ Cells ◽  
Rana Esculenta ◽  
Bufo Bufo ◽  
Discoglossus Pictus ◽  
Early Appearance ◽  
Vegetative Pole

The early appearance of the ‘germinal cytoplasm’ and its behaviour during the formation of cells which are thought to represent the primordial germ cells have been described in detail for Rana temporaria by Bounoure (1927, 1934, 1939) and Blackler (1958). These observations were extended to Xenopus laevis (Nieuwkoop, 1956; Nieuwkoop & Faber, 1956; Blackler, 1958), Bufo bufo (Blackler, 1958), Rana pipiens (Berardino, 1961), Discoglossus pictus (Gipouloux, 1962 a) and Rana esculenta (Hammer, cited by Blackler, 1965 b). The above findings agree with respect to the earliest detection of the ‘germinal cytoplasm’. Its first appearance was noticed as early as in the fertilized, unsegmented egg, where small, distinctly staining islands of cytoplasm are localized just under the cell membrane in an area around the vegetative pole of the egg. During cleavage the ‘germinal cytoplasm’ is distributed between the vegetative blastomeres directly surrounding the vegetative pole.

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