Abstract
1. Resting membrane potentials (RMPs), spontaneous miniature end-plate potentials (m.e.p.p.s), and evoked end-plate potentials (e.p.p.s) were recorded in phrenic nerve-hemidiaphragm preparations from rats at ages from 11 to 375 days. 2. The mean RMP increased from -64.1 +/- 1.2 mV (mean +/- S.E.) at age 11 days to -71.3 +/- 1.0 mV at age 30 days, after which there was no significant change with age. 3. The mean amplitude of m.e.p.p.s decreased from 1.088 +/- 0.070 mV at 11 days of age to 0.405 +/- 0.030 mV at 175 days of age, after which there was no significant change. 4. There was a rpaid, large increase in the frequency of m.e.p.p.s from 0.02/sec to 0.97/sec (geometric means) between 11 and 23 days of age, followed by a slower increase to 3.19/sec at 175 days of age. Subsequently there was a decrease by 2.58/sec at 375 days of age. 5. The mean of quantum content of plateau e.p.p.s elicited at a frequency of 10 Hz increased from 20.5 quanta/e.p.p. to 169.9 quanta/e.p.p. (geometric means) between 11 and 175 days of age and then decreased to 120.4 quanta/e.p.p. at 375 days of age. 6. The mean quantum content of the first e.p.p.s of trains of e.p.p.s increased from 44.2 quanta/e.p.p. to 468.8 quanta/e.p.p. (geometric means) between 11 and 175 days of age and then decreased to 358.1 quanta/e.p.p. at 375 days of age. 7. The calculated safety factor of neuromuscular transmission increased with age up to 110-175 days and subsequently decreased. 8. The change in all the above parameters occurred most rapidly in the first 6 weeks of life. The rapidity of these changes indicates that great care must be taken to ensure that control and experimental animals are adequately matched according to age, especially when rats weighing less than about 300 g are used.
Full text
PDF











Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- BOYD I. A., MARTIN A. R. The end-plate potential in mammalian muscle. J Physiol. 1956 Apr 27;132(1):74–91. doi: 10.1113/jphysiol.1956.sp005503. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BUSH G. H., STEAD A. L. The use of d-tubocurarine in neonatal anaesthesia. Br J Anaesth. 1962 Oct;34:721–728. doi: 10.1093/bja/34.10.721. [DOI] [PubMed] [Google Scholar]
- DIAMOND J., MILEDI R. A study of foetal and new-born rat muscle fibres. J Physiol. 1962 Aug;162:393–408. doi: 10.1113/jphysiol.1962.sp006941. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Elmqvist D., Quastel D. M. A quantitative study of end-plate potentials in isolated human muscle. J Physiol. 1965 Jun;178(3):505–529. doi: 10.1113/jphysiol.1965.sp007639. [DOI] [PMC free article] [PubMed] [Google Scholar]
- FATT P., KATZ B. An analysis of the end-plate potential recorded with an intracellular electrode. J Physiol. 1951 Nov 28;115(3):320–370. doi: 10.1113/jphysiol.1951.sp004675. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gutmann E., Hanzlíková V., Vysokocil F. Age changes in cross striated muscle of the rat. J Physiol. 1971 Jul;216(2):331–343. doi: 10.1113/jphysiol.1971.sp009528. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KATZ B., THESLEFF S. On the factors which determine the amplitude of the miniature end-plate potential. J Physiol. 1957 Jul 11;137(2):267–278. doi: 10.1113/jphysiol.1957.sp005811. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kelly A. M., Zacks S. I. The fine structure of motor endplate morphogenesis. J Cell Biol. 1969 Jul;42(1):154–169. doi: 10.1083/jcb.42.1.154. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kelly A. M., Zacks S. I. The histogenesis of rat intercostal muscle. J Cell Biol. 1969 Jul;42(1):135–153. doi: 10.1083/jcb.42.1.135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuno M., Turkanis S. A., Weakly J. N. Correlation between nerve terminal size and transmitter release at the neuromuscular junction of the frog. J Physiol. 1971 Mar;213(3):545–556. doi: 10.1113/jphysiol.1971.sp009399. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MARTIN A. R. A further study of the statistical composition on the end-plate potential. J Physiol. 1955 Oct 28;130(1):114–122. doi: 10.1113/jphysiol.1955.sp005397. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marshall M. W., Ward M. R. Anode break excitation in denervated rat skeletal muscle fibres. J Physiol. 1974 Jan;236(2):413–420. doi: 10.1113/jphysiol.1974.sp010443. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin A. R. The effect of membrane capacitance on non-linear summation of synaptic potentials. J Theor Biol. 1976 Jun;59(1):179–187. doi: 10.1016/s0022-5193(76)80031-8. [DOI] [PubMed] [Google Scholar]
- Miyamoto M. D. Binomial analysis of quantal transmitter release at glycerol treated frog neuromuscular junctions. J Physiol. 1975 Aug;250(1):121–142. doi: 10.1113/jphysiol.1975.sp011045. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Moore M. J., Rebeiz J. J., Holden M., Adams R. D. Biometric analyses of normal skeletal muscle. Acta Neuropathol. 1971;19(1):51–69. doi: 10.1007/BF00690954. [DOI] [PubMed] [Google Scholar]
- Paton W. D., Waud D. R. The margin of safety of neuromuscular transmission. J Physiol. 1967 Jul;191(1):59–90. doi: 10.1113/jphysiol.1967.sp008237. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rowe R. W., Goldspink G. Muscle fibre growth in five different muscles in both sexes of mice. J Anat. 1969 May;104(Pt 3):519–530. [PMC free article] [PubMed] [Google Scholar]
- Stevens C. F. A comment on Martin's relation. Biophys J. 1976 Aug;16(8):891–895. doi: 10.1016/S0006-3495(76)85739-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- TAKEUCHI A., TAKEUCHI N. Further analysis of relationship between end-plate potential and end-plate current. J Neurophysiol. 1960 Jul;23:397–402. doi: 10.1152/jn.1960.23.4.397. [DOI] [PubMed] [Google Scholar]
- Tucek S. Choline acetyltransferase activity in rat skeletal muscles during postnatal development. Exp Neurol. 1972 Aug;36(2):378–388. doi: 10.1016/0014-4886(72)90031-3. [DOI] [PubMed] [Google Scholar]
- Vyskocil F., Gutmann E. Spontaneous transmitter release from nerve endings and contractile properties in the soleus and diaphragm muscles of senile rats. Experientia. 1972 Mar 15;28(3):280–281. doi: 10.1007/BF01928688. [DOI] [PubMed] [Google Scholar]