scholarly journals The secreto-motor effects in the cat's foot studied by the electrometer.

1904 ◽  
Vol 73 (488-496) ◽  
pp. 92-98 ◽  
Author(s):  
Augustus Desire Waller
Keyword(s):  
Sciatic Nerve ◽  
Single Stimulus ◽  
Motor Action ◽  
Voluntary Muscle ◽  
Previous Communication ◽  
The Difference ◽  
Single Response ◽  
Motor Effects

In a previous communication it was stated that the electrical signs a of secreto-motor action by tetanisation of the sciatic nerve are a demonstrable in the pads of a cat’s foot after death, best so during; the second half-hour after death, when the action of the nerve upon muscles of the limb has ceased. The subsequent study of these effects, by means of electrometer records, has brought out with great distinctness the chief classical events with which we are familiar in the case of the contraction of voluntary muscle, viz., the latency and course of a single response to a single stimulus, the super-position of two or more responses and the composition of tetanus, summation of stimuli, fatigue and recovery, and the staircase phenomenon. The difference between the muscular and the secreto-motor series of phenomena is principally a difference of time, the former being about 100 times more rapid than the latter.

Effect of Reinforcement of the Negative Discriminandum in Differential Conditioning

1964 ◽  
Vol 14 (1) ◽  
pp. 107-110 ◽  
Author(s):  
Peter J. Donovick ◽  
Leonard E. Ross
Keyword(s):  
Phase I ◽  
Discrimination Learning ◽  
Differential Conditioning ◽  
Discrimination Problem ◽  
Single Stimulus ◽  
Female Rats ◽  
Second Phase ◽  
Learning Situation ◽  
Learning Conditions ◽  
The Difference

The present investigation was concerned with the reduction of inhibition associated with the negative discriminandum in a single stimulus discrimination learning situation. In Phase I 33 female rats were trained on a black-white discrimination problem. In the second phase Ss were divided into three groups which received: (a) 100% reinforcement to both the old positive and negative discriminanda; (b) four trials per day to the old negative, 100% reward; (c) eight trials per day to the old negative, 100% reward. As in previous studies, which employed simultaneous discrimination learning conditions, speed to the old negative remained significantly below speed to the old positive in the second phase. However, unlike the previous results, the difference decreased over trials. No differences were found between the groups that had trials to the old negative cue only, or between these groups and either speed to the old positive or the old negative in the case of the group receiving reward on both cues.

Chorda tympani section decreases the cation specificity of depletion-induced sodium appetite in rats

1993 ◽  
Vol 264 (2) ◽  
pp. R319-R323 ◽  
Author(s):  
P. A. Breslin ◽  
A. C. Spector ◽  
H. J. Grill
Keyword(s):  
Lick Rate ◽  
Single Stimulus ◽  
The Other ◽  
Chloride Salt ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Diuretic Treatment ◽  
Sodium Appetite ◽  
The Difference ◽  
Chloride Salts

Rats depleted of sodium by diuretic treatment were tested for their ability to respond selectively to NaCl after chorda tympani nerve (CTn) section (CTX). A variety of chloride salts (NaCl, KCl, NH4Cl, CaCl2) at two concentrations (0.05 and 0.3 M) were presented semirandomly to sodium-deplete rats in repeated single-stimulus trials (10 s). The responses of sodium-depleted surgical control rats (n = 8) were highly cation specific. These rats licked substantially more for both sodium stimuli than for any other chloride salt. On the other hand, the licking responses of CTX sodium-depleted rats (n = 8) were less cation selective. These rats licked NaCl and 0.05 M KCl at comparable rates. For both NaCl concentrations, CTX rats had significantly lower lick rates than controls. In addition, the difference between the lick rate for NaCl and that for the other salts was much greater for control rats than for CTX rats. Although CTn section did not entirely eliminate the high levels of responsivity to NaCl observed in the intact sodium-depleted rat, it did substantially compromise the selectivity of the behavior, which suggests that the input of the CTn is critical for taste-guided sodium specific behaviors.

scholarly journals An investigation of the attack of platinum and tungsten by Iodine

1931 ◽  
Vol 134 (824) ◽  
pp. 385-404 ◽  
Keyword(s):  
Molecular Structure ◽  
Thermionic Emission ◽  
Previous Communication ◽  
Work Functions ◽  
Gas Reactions ◽  
The Difference ◽  
Low Pressures ◽  
And Tungsten

The reactions which are most likely to prove fruitful in elucidating the mechanism of heterogeneous gas reactions are those involving gases having a simple molecular structure, and an investigation was therefore begun by studying the attack of platinum by oxygen at low pressures, as reported in a previous communication. These investigations have now been extended to the reactions of platinum and tungsten with iodine vapour at low pressures. A marked difference in the behaviour of the two metals was to be anticipated from several considerations, firstly, tungsten is much more readily attacked by oxygen than is platinum, and secondly, the effect of iodine on the thermionic emission is different for the two metals. Kalandyk observed that the emission from platinum was greatly enhanced by iodine vapour, whereas Langmuir found that iodine had no influence on the emission from tungsten. The difference in the case of oxidation was accounted for in terms of the large difference in the work functions of the two metals. The thermionic data show that the adsorption of iodine on platinum is stronger than on tungsten, and this can also be ascribed to the difference in the work functions.

scholarly journals Electrophysiologic assessment of regeneration in rat sciatic nerve repair using suture, fibrin glue or a combination of both techniques

2005 ◽  
Vol 63 (3a) ◽  
pp. 601-604 ◽  
Author(s):  
Roberto Sergio Martins ◽  
Mario Gilberto Siqueira ◽  
Ciro Ferreira da Silva ◽  
Benedito Ortiz de Godoy ◽  
José Píndaro Pereira Plese
Keyword(s):  
Sciatic Nerve ◽  
Action Potential ◽  
Fibrin Glue ◽  
Conduction Velocity ◽  
Nerve Section ◽  
Motor Action ◽  
Rat Sciatic Nerve ◽  
Nerve Action ◽  
Group A ◽  
Group B

We evaluated the repair of seccioned rat sciatic nerve by the comparison of electrophysiologic parameters. The repair was effected with suture (group A), fibrin glue (group B) or a combination of both techniques (group C). The amplitude, latency and conduction velocity of the motor and nerve action potentials were assessed before the nerve section and at reoperation after 24 weeks. There was no difference between the groups when the nerve action potential was evaluated. Rats of group B presented better results than those of group A (p<0.05) when latency and the nerve conduction velocity assessed at the reoperation, and the ratio between the conduction velocity at the reoperation and before the nerve section in the motor action potential evaluation were measured. Animals of group C presented better results than those of group A when the ratio between the conduction velocity of motor action potential at the reoperation and before the nerve division was considered (p<0.05). No difference between groups B and C was found. We conclude that repair using fibrin glue presented better results than suture following transection of sciatic nerve when the motor action potential was evaluated in the rat experimental model.

scholarly journals XII.—The Pharmacological Action of Protocatechyl-Tropeine.

1910 ◽  
Vol 47 (2) ◽  
pp. 273-285 ◽  
Author(s):  
C. R. Marshall
Keyword(s):  
Hydroxy Acid ◽  
Pharmacological Action ◽  
Vagal Nerve ◽  
Nerve Endings ◽  
Voluntary Muscle ◽  
Respiratory Centre ◽  
The Difference ◽  
Image Position

Protocatechyl-tropeine is one of a series of new tropeines investigated primarily with the object of determining the difference in pharmacological action between a lactone and the corresponding hydroxy-acid. Its constitution is shown in the following formula :—Like most other tropeines, it paralyses the vagal nerve endings in the heart. It also diminishes the irritability of voluntary muscle and its myo-neural junctions, and paralyses the respiratory centre.

scholarly journals I. On the new gas obtained from uraninite. Second note

1895 ◽  
Vol 58 (347-352) ◽  
pp. 113-116
Keyword(s):  
The Other ◽  
Solar Chromosphere ◽  
Previous Communication ◽  
The Difference ◽  
Complex Origin

Since my communication on the gas obtained from uraninite (bröggerite) was sent into the Society, on the 25th ultimo, I have been employing the method I there referred to in several directions, among them to determine whether the spectrum of the gas indicates a simple or a complex origin. I was led to make this special inquiry on account of the difference in the frequency of the appearance of D 3 and the other lines to which I referred in the previous communication in the solar chromosphere. For instance, if we take the lines D 3 , 4471, and 4302, the frequencies are as follows, according to Young:—

Axonal cross-excitation in nerve-end neuromas: comparison of A- and C-fibers

1992 ◽  
Vol 68 (4) ◽  
pp. 1160-1166 ◽  
Author(s):  
R. Amir ◽  
M. Devor
Keyword(s):  
Sciatic Nerve ◽  
Tetanic Stimulation ◽  
Impulse Discharge ◽  
C Fibers ◽  
Stimulation Parameters ◽  
The Difference ◽  
Stimulation Of

1. We recorded from single afferent axons ending in chronic sciatic nerve end neuromas in rats with the use of the teased-fiber method. Axons were sought that had ongoing impulse discharge originating in the neuroma. 2. Recording from myelinated (A-) fibers, tetanic stimulation of neighboring axons (50 Hz, 5 or 10 s, intensity adequate to drive A-fibers) caused an increase, and sometimes a decrease, in the rate of ongoing discharge in 68% of the fibers tested. In addition, some initially silent neuroma A-fibers (1.4%) were activated in this way. Both A beta and A delta fibers responded, although the likelihood of response was greater in A beta fibers. We call this form of interfiber cross-excitation "crossed afterdischarge." 3. In contrast to A-fibers, crossed afterdischarge was evoked with these stimulation parameters in < or = 5% of the spontaneously active unmyelinated (C-) fibers sampled. No initially silent C-fibers were activated. 4. C-fibers remained largely insensitive to cross-excitation by neighboring axons even when the strength of stimulus pulses was increased so as to include neighboring A + C-fibers. 5. The difference between A- and C-fibers could not be accounted for on the basis of the maturity of the neuroma, rate and pattern of ongoing discharge, or use of Flaxedil paralysis. 6. The difference between A- and C-fibers is discussed in terms of two alternative mechanisms that may underlie crossed afterdischarge: mediation by a neurotransmitter(s) in a nonsynaptic mode, and mutual K+ depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals III. Note on the influence of liquor potassæ and an elevated temperature on the origin and growth of microphytes

1877 ◽  
Vol 25 (171-178) ◽  
pp. 454-456
Keyword(s):  
Elevated Temperature ◽  
Royal Society ◽  
De Novo ◽  
General Rule ◽  
Positive Influence ◽  
Positive Power ◽  
Acid Infusion ◽  
Acid Urine ◽  
Previous Communication ◽  
The Difference

In a recent communication to the Royal Society, Dr. Bastian brought forward some experiments to show that while an acid urine usually remains barren after being boiled a few minutes, the same urine becomes fertile when similarly treated if previously neutralized or rendered alkaline by liquor potassæ, especially if it be afterwards maintained at a temperature of 115° F. or 122° F. In this respect urine only conforms to the general rule observed by myself and formulated in my previous communication to the Society—that “slightly alkaline liquids were always more difficult to sterilize (by heat) than slightly acid liquids.” This difference came out strongest in my own experiments in the case of hay-infusion—the acid infusion invariably remaining barren after a few minutes boiling, and the neutralized infusion invariably becoming fertile after a similar boiling. Accordingly I utilized hay-infusion to determine the cause of the difference in question. It could evidently only be due to one of two things—either (1) the change of reaction enabled germs preexisting in the infusion to survive the ebullition, or (2) the addition of the alkali exercised a positive influence in exciting a de novo generation of organisms. To decide which of these two interpretations was the true one, an experiment was contrived in which the liq. potassæ could be added to the infusion not before, but after it had been boiled, and thereby rendered permanently sterile. When added in this way, I found that liquor potassæ had not any power to excite germination. The infusions invariably remained barren when the alkali was added to them after they had been sterilized. I therefore concluded that the effect of the change of reaction consisted simply in enabling preexisting germs to survive a brief ebullition. Dr. Bastian, in repeating this experiment in the case of urine, arrived at an opposite conclusion: he found that whether the alkali was added before or after ebullition he obtained the same result—the urine in both cases became fertile; and he concluded that the alkali had a positive power of promoting the origin of organisms in the urine.

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