Abstract
According to theory, the action of acetylcholine (ACh) and ACh-esterase is essential for the permeability changes of excitable membranes during activity. It is, therefore, pertinent to know the activity of ACh-esterase per unit axonal surface area instead of per gram nerve, as it has been measured in the past. Such information has now been obtained with the newly developed microgasometric technique using a magnetic diver. (1) The cholinesterase (Ch-esterase) activity per mm2 surface of sensory axons of the walking leg of lobster is 1.2 x 10-3 µM/hr. (σ = ± 0.3 x 10-3; SE = 0.17 x 10-3); the corresponding value for the motor axons isslightly higher: 1.93 x 10-3 µM/hr. (σ = ± 0.41 x 10-3; SE = ± 0.14 x 10-3). Referred to gram nerve, the Ch-esterase activity of the sensory axons is much higher than that of the motor axons: 741 µM/hr. (σ = ± 73.5; SE = ± 32.6) versus 111.6 µM/hr. (σ = ± 28.3; SE = ± 10). (2) The enzyme activity in the small fibers of the stellar nerve of squid is 3.2 x 10-4 µM/mm2/hr. (σ = ± 0.96 x 10-4; SE = ± 0.4 x 10-4). (3) The Ch-esterase activity per mm2 surface of squid giant axon is 9.5 x 10-5 µM/hr. (σ = ± 1.55 x 10-5; SE = ± 0.38 x 10-5). The value was obtained with small pieces of carefully cleaned axons after removal of the axoplasm and exposure to sonic disintegration. Without the latter treatment the figurewas 3.85 x 10-5 µM/mm2/hr. (σ = ± 3.24 x 10-5; SE = ± 0.93 x 10-5). The experiments indicate the existence of permeability barriers in the cell wall surrounding part of the enzyme, since the substrate cannot reach all the enzyme even when small fragments of the cell wall are used without disintegration. (4) On the basis of the data obtained, some tentative approximations are made of the ratio of ACh released to Na ions entering the squid giant axon per cm2 per impulse.
Full Text
The Full Text of this article is available as a PDF (767.0 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ALDRIDGE W. N., JOHNSON M. K. Cholinesterase, succinic dehydrogenase, nucleic acids, esterase and glutathione reductase in sub-cellular fractions from rat brain. Biochem J. 1959 Oct;73:270–276. doi: 10.1042/bj0730270. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BARRNETT R. J. The fine structural localization of acetylcholinesterase at the myoneural junction. J Cell Biol. 1962 Feb;12:247–262. doi: 10.1083/jcb.12.2.247. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BRZIN M., KOVIC M., OMAN S. THE MAGNETIC DIVER BALANCE. C R Trav Lab Carlsberg. 1964;34:407–426. [PubMed] [Google Scholar]
- Boell E. J., Nachmansohn D. LOCALIZATION OF CHOLINE ESTERASE IN NERVE FIBERS. Science. 1940 Nov 29;92(2396):513–514. doi: 10.1126/science.92.2396.513. [DOI] [PubMed] [Google Scholar]
- DETTBARN W. D., DAVIS F. A. Effects of acetylcholine on axonal conduction of lobster nerve. Biochim Biophys Acta. 1963 May 21;66:397–405. doi: 10.1016/0006-3002(63)91208-3. [DOI] [PubMed] [Google Scholar]
- DETTBARN W. D. DISTINCTION BETWEEN ACTION ON ACETYLCHOLINESTERASE AND ON ACETYLCHOLINE RECEPTOR IN AXONS. Biochim Biophys Acta. 1964 May 25;79:629–630. doi: 10.1016/0926-6577(64)90232-3. [DOI] [PubMed] [Google Scholar]
- DETTBARN W. D. HYDROLYSIS OF CHOLINE ESTERS IN INVERTEBRATE NERVE FIBERS. Biochim Biophys Acta. 1963 Nov 8;77:430–435. doi: 10.1016/0006-3002(63)90517-1. [DOI] [PubMed] [Google Scholar]
- KEYNES R. D., LEWIS P. R. The sodium and potassium content of cephalopod nerve fibers. J Physiol. 1951 Jun;114(1-2):151–182. doi: 10.1113/jphysiol.1951.sp004609. [DOI] [PMC free article] [PubMed] [Google Scholar]
- KOELLE G. B., FRIEDENWALD J. A. A histochemical method for localizing cholinesterase activity. Proc Soc Exp Biol Med. 1949 Apr;70(4):617–622. doi: 10.3181/00379727-70-17013. [DOI] [PubMed] [Google Scholar]
- LEVIN Y., PECHT M., GOLDSTEIN L., KATCHALSKI E. A WATER-INSOLUBLE POLYANIONIC DERIVATIVE OF TRYPSIN. I. PREPARATION AND PROPERTIES. Biochemistry. 1964 Dec;3:1905–1913. doi: 10.1021/bi00900a021. [DOI] [PubMed] [Google Scholar]
- LEVIN Y., PECHT M., GOLDSTEIN L., KATCHALSKI E. A WATER-INSOLUBLE POLYANIONIC DERIVATIVE OF TRYPSIN. I. PREPARATION AND PROPERTIES. Biochemistry. 1964 Dec;3:1905–1913. doi: 10.1021/bi00900a021. [DOI] [PubMed] [Google Scholar]
- Marnay A., Nachmansohn D. Choline esterase in voluntary muscle. J Physiol. 1938 Feb 16;92(1):37–47. doi: 10.1113/jphysiol.1938.sp003582. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ROSENBERG P., EHRENPREIS S. Reversible block of axonal conduction by curare after treatment with cobra venom. Biochem Pharmacol. 1961 Sep;8:192–206. doi: 10.1016/0006-2952(61)90002-8. [DOI] [PubMed] [Google Scholar]
- ROSENBERG P., PODLESKI T. R. ABILITY OF VENOMS TO RENDER SQUID AXONS SENSITIVE TO CURARE AND ACETYLCHOLINE. Biochim Biophys Acta. 1963 Jul 23;75:104–115. doi: 10.1016/0006-3002(63)90584-5. [DOI] [PubMed] [Google Scholar]
- TOSCHI G. A biochemical study of brain microsomes. Exp Cell Res. 1959 Feb;16(2):232–255. doi: 10.1016/0014-4827(59)90252-6. [DOI] [PubMed] [Google Scholar]
- ZAJICEK J., ZEUTHEN E. Quantitative determination by a special "ampulla-diver" of cholinesterase activity in individual cells, with notes on other uses of the method. Gen Cytochem Methods. 1961;2:131–152. doi: 10.1016/b978-0-12-395584-5.50008-1. [DOI] [PubMed] [Google Scholar]
