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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
2
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pubmed:dateCreated |
1979-1-15
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pubmed:abstractText |
1. Action potentials and their maximum rates of rise, VA, were measured in single myelinated nerve fibres of the frog, Rana esculenta at room temperature. 2. On applying 1 mM procaine (pH 7.2) at 20 Hz stimulus frequency, half of the final VA reduction was reached at ton = 0.27 s; on applying 0.5 mM benzocaine (pH 7,2) at 50 HZ, ton was 0.12 s. Increasing the stimulus frequency between 2 and 50 HZ increased the rate of block by procaine but not by benzocaine. 3. Recovery in Ringer solution (pH 7.2) from 30-s treatment with 1 mM procaine (pH 7.2), the equieffective 0.15 mM procaine (pH 8.9) and from 0.5 mM benzocaine (pH 7.2) was 54%, 31% and 70%, respectively, within 1 s. 4. Changing between alkaline Ringer solution (pH 8.9) and 1 mM procaine (pH 7.2) led to transitory excessive block. Changing between 1 mM procaine (pH 7.2) and acid Ringer solution (pH 6.0) and washing out 10 mM procaine (pH 5.5) with neutral Ringer solution also led to a non-monotonic change in VA. 5. If hyperpolarizing pulses (30 ms, 20 mV) preceded the stimuli, changing the frequency of the pulse pairs led to a gradual moderate relief of block in procaine, turning off prepulses (at 10 HZ) to a gradual increase of block. In benzocaine changing from 1 to 10 HZ had no effect but turning off prepulses led to a prompt large increase of block. In procaine + benzocaine the membrane responded much as in benzocaine alone. At 1 HZ (prepulses) VA in 0.4 mM procaine was smaller than in 0.4 mM procaine + 0.3 mM benzocaine. 6. These phenomena can be explained on the assumption of voltage-dependent binding of benzocaine and procaine to a common receptor. The rate of block appears to be limited by access to the receptor, more in the case of benzocaine than of procaine.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Sep
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pubmed:issn |
0031-6768
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
6
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pubmed:volume |
376
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
105-18
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pubmed:dateRevised |
2006-11-15
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pubmed:meshHeading |
pubmed-meshheading:30940-Action Potentials,
pubmed-meshheading:30940-Animals,
pubmed-meshheading:30940-Anura,
pubmed-meshheading:30940-Benzocaine,
pubmed-meshheading:30940-Calcium,
pubmed-meshheading:30940-Drug Interactions,
pubmed-meshheading:30940-Electric Stimulation,
pubmed-meshheading:30940-Hydrogen-Ion Concentration,
pubmed-meshheading:30940-Kinetics,
pubmed-meshheading:30940-Models, Biological,
pubmed-meshheading:30940-Procaine,
pubmed-meshheading:30940-Rana esculenta,
pubmed-meshheading:30940-Ranvier's Nodes
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pubmed:year |
1978
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pubmed:articleTitle |
Rates of block by procaine and benzocaine and the procaine-benzocaine interaction at the node of Ranvier.
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pubmed:publicationType |
Journal Article,
In Vitro
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