QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by STEPHENS, P. J. Articles by MINDREBO, N. Search for Related Content PubMed Articles by STEPHENS, P. J. Articles by MINDREBO, N.

Journal of Experimental Biology 103,289-301 (1983)
Published by Company of Biologists 1983

Effects of Ethanol and Temperature on a Crab Motor Axon Action Potential: A Possible Mechanism for Peripheral Spike Generation

PHILIP J. STEPHENS ¹, PAUL A. FRASCELLA ¹, and NORMAN MINDREBO ¹

¹ Villanova University, Department of Biology, Villanova, Pa. 19085, U.S.A.

1. In autotomized walking limbs of Pachygrapsus crassipes, microelectrode recordings of evoked action potentials were made in the meropodite from the E2 excitor axon to the bender muscle.

2. The action potential spike was followed by a depolarizing after-potential. Increases in temperature resulted in a decline in the amplitude and time course of the spike, and an increase in the amplitude of the after-potential. Low levels of ethanol or increased levels of calcium increased the size of the after-potential and decreased the temperature threshold for peripheral spike generation.

3. At high temperatures a single orthodromic E2 axon spike provoked the generation of additional impulses at the periphery, with an inter-spike interval of 2-3.5 ms.

4. The after-potential lasted longer than the refractory period following the spike. The axon membrane, therefore, was depolarized after the refractory period and this resulted in a period of low threshold for spike generation. Increases in temperature shortened the refractory period.

5. We suggest that additional spikes are generated at the periphery where the E2 axon diameter is decreased. The increased membrane resistance at these sites increases the size of the depolarizing after-potential. Therefore, if the depolarization following the refractory period is at or above threshold for firing, additional action potentials will be generated at the periphery.

Key words: Crab, axon, temperature

Submitted on July 13, 1982
Accepted on November 10, 1982

This article has been cited by other articles:

				M. Msghina, C. K. Govind, and H. L. Atwood Synaptic Structure and Transmitter Release in Crustacean Phasic and Tonic Motor Neurons J. Neurosci., February 15, 1998; 18(4): 1374 - 1382. [Abstract] [Full Text] [PDF]