Abstract
Temperature characteristics of excitability in the squid giant axon were measured for the space-clamped axon with the double sucrose gap technique. Threshold strength-duration curves were obtained for square wave current pulses from 10 µsec to 10 msec and at temperatures from 5°C to 35°C. The threshold change of potential, at which an action potential separated from a subthreshold response, averaged 17 mv at 20°C with a Q 10 of 1.15. The average threshold current density at rheobase was 12 µa/cm2 at 20°C with a Q 10 of 2.35 compared to 2.3 obtained previously. At short times the threshold charge was 1.5·10-8 coul/cm2. This was relatively independent of temperature and occasionally showed a minimum in the temperature range. At intermediate times and all temperatures the threshold currents were less than for both the single time constant model and the two factor excitation process as developed by Hill. FitzHugh has made computer investigations of the effect of temperature on the excitation of the squid axon membrane as represented by the Hodgkin-Huxley equations. These are in general in good agreement with our experimental results.
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Selected References
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- Blair H. A. ON THE INTENSITY-TIME RELATIONS FOR STIMULATION BY ELECTRIC CURRENTS. I. J Gen Physiol. 1932 Jul 20;15(6):709–729. doi: 10.1085/jgp.15.6.709. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fitzhugh R. Theoretical effect of temperature on threshold in the Hodgkin-Huxley nerve model. J Gen Physiol. 1966 May;49(5):989–1005. doi: 10.1085/jgp.49.5.989. [DOI] [PMC free article] [PubMed] [Google Scholar]
- GUTTMAN R. Effect of temperature on the potential and current thresholds of axon membrane. J Gen Physiol. 1962 Nov;46:257–266. doi: 10.1085/jgp.46.2.257. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HAGIWARA S., OOMURA Y. The critical depolarization for the spike in the squid giant axon. Jpn J Physiol. 1958 Sep 15;8(3):234–245. doi: 10.2170/jjphysiol.8.234. [DOI] [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F. A quantitative description of membrane current and its application to conduction and excitation in nerve. J Physiol. 1952 Aug;117(4):500–544. doi: 10.1113/jphysiol.1952.sp004764. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., HUXLEY A. F., KATZ B. Measurement of current-voltage relations in the membrane of the giant axon of Loligo. J Physiol. 1952 Apr;116(4):424–448. doi: 10.1113/jphysiol.1952.sp004716. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HODGKIN A. L., KATZ B. The effect of temperature on the electrical activity of the giant axon of the squid. J Physiol. 1949 Aug;109(1-2):240–249. doi: 10.1113/jphysiol.1949.sp004388. [DOI] [PMC free article] [PubMed] [Google Scholar]
- JULIAN F. J., MOORE J. W., GOLDMAN D. E. Membrane potentials of the lobster giant axon obtained by use of the sucrose-gap technique. J Gen Physiol. 1962 Jul;45:1195–1216. doi: 10.1085/jgp.45.6.1195. [DOI] [PMC free article] [PubMed] [Google Scholar]
- SJODIN R. A., MULLINS L. J. Oscillatory behavior of the squid axon membrane potential. J Gen Physiol. 1958 Sep 20;42(1):39–47. doi: 10.1085/jgp.42.1.39. [DOI] [PMC free article] [PubMed] [Google Scholar]