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. 1986 Mar;372:363–377. doi: 10.1113/jphysiol.1986.sp016013

Calcium uptake of rat brain synaptosomes as a function of membrane potential under different depolarizing conditions.

V Adam-Vizi, E Ligeti
PMCID: PMC1192767  PMID: 3723411

Abstract

The uptake of 45Ca2+ was measured in brain synaptosomes under conditions designed to depolarize the membranes. Membrane potential was estimated from the distribution of 86Rb+ between the intra- and extracellular compartments. K+ depolarization (8-60 mM) only increased "a2+ uptake beyond a threshold depolarization of about 10 mV, whereas veratridine (5-40 microM) induced an increased Ca2+ uptake at a concentration which depolarized the membrane less than this threshold. Ouabain did not enhance Ca2+ uptake, but the depolarization it produced did not reach threshold. Ca2+ influx already stimulated by K+ depolarization can be further enhanced by veratridine without any parallel change in membrane potential. Only the pathway mediating Ca2+ uptake during K+ depolarization can be inactivated: Ca2+ uptake evoked by K+ depolarization is decreased in synaptosomes pre-depolarized in the presence of a high concentration of K+. In contrast, pre-depolarization does not change Ca2+ uptake evoked by veratridine. Ca2+ channel blockers, such as verapamil and diltiazem but not nifedipine, in concentrations of 10-100 microM, decrease the stimulation of Ca2+ uptake by high K+ concentration without influencing depolarization, whereas the effect of veratridine on Ca2+ uptake is only inhibited when its effect on Na+ channels is also prevented. It is concluded that Ca2+ uptake during K+ depolarization proceeds through voltage-dependent Ca2+ channels similar to those of squid axon, whereas veratridine activates an additional Ca2+ entry, possibly via influx through open Na+ channels. Different quantitative relationships are found between acetylcholine release of synaptosomes and the amount of Ca2+ taken up by different mechanisms: the same amount of Ca2+ uptake is accompanied by a greater increase of acetylcholine release if the uptake is induced by K+ depolarization rather than veratridine.

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Selected References

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  1. Adam-Vizi V., Ligeti E. Release of acetylcholine from rat brain synaptosomes by various agents in the absence of external calcium ions. J Physiol. 1984 Aug;353:505–521. doi: 10.1113/jphysiol.1984.sp015348. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Akerman K. E., Nicholls D. G. Intrasynaptosomal compartmentation of calcium during depolarization-induced calcium uptake across the plasma membrane. Biochim Biophys Acta. 1981 Jul 6;645(1):41–48. doi: 10.1016/0005-2736(81)90509-5. [DOI] [PubMed] [Google Scholar]
  3. Baker P. F., Hodgkin A. L., Ridgway E. B. Depolarization and calcium entry in squid giant axons. J Physiol. 1971 Nov;218(3):709–755. doi: 10.1113/jphysiol.1971.sp009641. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Baker P. F., Meves H., Ridgway E. B. Calcium entry in response to maintained depolarization of squid axons. J Physiol. 1973 Jun;231(3):527–548. doi: 10.1113/jphysiol.1973.sp010247. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Baker P. F., Meves H., Ridgway E. B. Effects of manganese and other agents on the calcium uptake that follows depolarization of squid axons. J Physiol. 1973 Jun;231(3):511–526. doi: 10.1113/jphysiol.1973.sp010246. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Blaustein M. P. Effects of potassium, veratridine, and scorpion venom on calcium accumulation and transmitter release by nerve terminals in vitro. J Physiol. 1975 Jun;247(3):617–655. doi: 10.1113/jphysiol.1975.sp010950. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Blaustein M. P., Goldring J. M. Membrane potentials in pinched-off presynaptic nerve ternimals monitored with a fluorescent probe: evidence that synaptosomes have potassium diffusion potentials. J Physiol. 1975 Jun;247(3):589–615. doi: 10.1113/jphysiol.1975.sp010949. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Brehm P., Eckert R. Calcium entry leads to inactivation of calcium channel in Paramecium. Science. 1978 Dec 15;202(4373):1203–1206. doi: 10.1126/science.103199. [DOI] [PubMed] [Google Scholar]
  9. Goddard G. A., Robinson J. D. Uptake and release of calcium by rat brain synaptosomes. Brain Res. 1976 Jul 9;110(2):331–350. doi: 10.1016/0006-8993(76)90406-6. [DOI] [PubMed] [Google Scholar]
  10. HODGKIN A. L., KEYNES R. D. Movements of labelled calcium in squid giant axons. J Physiol. 1957 Sep 30;138(2):253–281. doi: 10.1113/jphysiol.1957.sp005850. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Hagiwara S., Byerly L. Calcium channel. Annu Rev Neurosci. 1981;4:69–125. doi: 10.1146/annurev.ne.04.030181.000441. [DOI] [PubMed] [Google Scholar]
  12. Hajós F. An improved method for the preparation of synaptosomal fractions in high purity. Brain Res. 1975 Aug 15;93(3):485–489. doi: 10.1016/0006-8993(75)90186-9. [DOI] [PubMed] [Google Scholar]
  13. KATZ B., MILEDI R. THE EFFECT OF CALCIUM ON ACETYLCHOLINE RELEASE FROM MOTOR NERVE TERMINALS. Proc R Soc Lond B Biol Sci. 1965 Feb 16;161:496–503. doi: 10.1098/rspb.1965.0017. [DOI] [PubMed] [Google Scholar]
  14. Kostyuk P. G. Calcium channels in the neuronal membrane. Biochim Biophys Acta. 1981 Dec;650(2-3):128–150. doi: 10.1016/0304-4157(81)90003-4. [DOI] [PubMed] [Google Scholar]
  15. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  16. Llinás R., Blinks J. R., Nicholson C. Calcium transient in presynaptic terminal of squid giant synapse: detection with aequorin. Science. 1972 Jun 9;176(4039):1127–1129. doi: 10.1126/science.176.4039.1127. [DOI] [PubMed] [Google Scholar]
  17. Llinás R., Steinberg I. Z., Walton K. Presynaptic calcium currents and their relation to synaptic transmission: voltage clamp study in squid giant synapse and theoretical model for the calcium gate. Proc Natl Acad Sci U S A. 1976 Aug;73(8):2918–2922. doi: 10.1073/pnas.73.8.2918. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Meves H., Vogel W. Calcium inward currents in internally perfused giant axons. J Physiol. 1973 Nov;235(1):225–265. doi: 10.1113/jphysiol.1973.sp010386. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Meyer E. M., Cooper J. R. Cobalt-ions dissociate between calcium uptake through voltage-dependent sodium and calcium channels in synaptosomes. Brain Res. 1983 Apr 11;265(1):173–176. doi: 10.1016/0006-8993(83)91352-5. [DOI] [PubMed] [Google Scholar]
  20. Meyer E. M., Cooper J. R. Correlations between Na+-K+ ATPase activity and acetylcholine release in rat cortical synaptosomes. J Neurochem. 1981 Feb;36(2):467–475. doi: 10.1111/j.1471-4159.1981.tb01616.x. [DOI] [PubMed] [Google Scholar]
  21. Nachshen D. A., Blaustein M. P. Some properties of potassium-stimulated calcium influx in presynaptic nerve endings. J Gen Physiol. 1980 Dec;76(6):709–728. doi: 10.1085/jgp.76.6.709. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Nachshen D. A., Blaustein M. P. The effects of some organic "calcium antagonists" on calcium influx in presynaptic nerve terminals. Mol Pharmacol. 1979 Sep;16(2):576–586. [PubMed] [Google Scholar]
  23. Nachshen D. A. The early time course of potassium-stimulated calcium uptake in presynaptic nerve terminals isolated from rat brain. J Physiol. 1985 Apr;361:251–268. doi: 10.1113/jphysiol.1985.sp015644. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Nemeth E. F., Cooper J. R. Effect of somatostatin on acetylcholine release from rat hippocampal synaptosomes. Brain Res. 1979 Apr 6;165(1):166–170. doi: 10.1016/0006-8993(79)90057-x. [DOI] [PubMed] [Google Scholar]
  25. Pocock G. Ion movements in isolated bovine adrenal medullary cells treated with ouabain. Mol Pharmacol. 1983 May;23(3):681–697. [PubMed] [Google Scholar]
  26. Sandoval M. E. Sodium-dependent efflux of [3H]GABA from synaptosomes probably related to mitochondrial calcium mobilization. J Neurochem. 1980 Oct;35(4):915–921. doi: 10.1111/j.1471-4159.1980.tb07090.x. [DOI] [PubMed] [Google Scholar]
  27. Scott I. D., Nicholls D. G. Energy transduction in intact synaptosomes. Influence of plasma-membrane depolarization on the respiration and membrane potential of internal mitochondria determined in situ. Biochem J. 1980 Jan 15;186(1):21–33. doi: 10.1042/bj1860021. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Simmonds M. A. Effect of environmental temperature on the turnover of noradrenaline in hypothalamus and other areas of rat brain. J Physiol. 1969 Jul;203(1):199–210. doi: 10.1113/jphysiol.1969.sp008859. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Stahl W. L., Swanson P. D. Uptake of calcium by subcellular fractions isolated from ouabain-treated cerebral tissues. J Neurochem. 1969 Dec;16(12):1553–1563. doi: 10.1111/j.1471-4159.1969.tb10354.x. [DOI] [PubMed] [Google Scholar]
  30. Swanson P. D., Anderson L., Stahl W. L. Uptake of calcium ions by synaptosomes from rat brain. Biochim Biophys Acta. 1974 Jul 31;356(2):174–183. doi: 10.1016/0005-2736(74)90281-8. [DOI] [PubMed] [Google Scholar]
  31. Tillotson D. Inactivation of Ca conductance dependent on entry of Ca ions in molluscan neurons. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1497–1500. doi: 10.1073/pnas.76.3.1497. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Vyas S., Marchbanks R. M. The effect of ouabain on the release of [14C]acetylcholine and other substances from synaptosomes. J Neurochem. 1981 Dec;37(6):1467–1474. doi: 10.1111/j.1471-4159.1981.tb06316.x. [DOI] [PubMed] [Google Scholar]
  33. Wonnacott S., Marchbanks R. M., Fiol C. Ca2+ uptake by synaptosomes and its effect on the inhibition of acetylcholine release by botulinum toxin. J Neurochem. 1978 May;30(5):1127–1134. doi: 10.1111/j.1471-4159.1978.tb12407.x. [DOI] [PubMed] [Google Scholar]

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