Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1996 Jul 15;494(Pt 2):539–553. doi: 10.1113/jphysiol.1996.sp021512

Rapid exocytosis and endocytosis in nerve terminals of the rat posterior pituitary.

S F Hsu 1, M B Jackson 1
PMCID: PMC1160654  PMID: 8842011

Abstract

1. Ca(2+)-induced exocytosis and endocytosis were studied by measuring the membrane capacitance of voltage-clamped peptidergic nerve terminals in slices prepared from the rat posterior pituitary. 2. Depolarizing pulses produced rapid increases in capacitance. These increases varied in parallel with Ca2+ current as voltage was varied. Elimination of Ca2+ current blocked depolarization-induced capacitance changes. 3. Depolarization-induced capacitance changes increased with pulse duration. Capacitance changes also increased with integrated Ca2+ influx, but saturated at high levels of Ca2+ entry. This saturation allowed us to estimate a pool size of 190 vesicles, assuming each vesicle has a capacitance of 1 fF. Vesicles from this pool fused with a time constant of 0.43 s. The capacitance change increased with the first power of integrated Ca2+ influx. 4. Experiments with briefer pulses revealed a rapid component of exocytosis comprising a pool of forty vesicles that fuse with a time constant of 14 ms. This rapid process may reflect a final Ca(2+)-regulated triggering step, which is distinct from the slower kinetic step revealed by longer duration pulses. The slower step may reflect a priming of vesicles prior to exocytosis. 5. Depolarization-induced capacitance increases in most cases were followed by a rapid decay in capacitance, reflecting membrane reuptake tightly coupled to exocytosis. A variable amount of rapid endocytosis followed depolarization-induced capacitance increases. The time constant for rapid endocytosis to baseline was 0.44 s. Excess endocytosis was occasionally observed, with capacitance decaying below the pre-stimulus baseline with a time constant of 2.1 s. 6. Rapid endocytosis was slower after pulses that produced greater increases in intracellular Ca2+, consistent with the hypothesis that intracellular Ca2+ inhibits rapid endocytosis. 7. Exocytosis follows depolarization with no detectable delay, indicating that Ca2+ triggers neuropeptide secretion from nerve terminals with kinetics comparable to that observed in other rapidly secreting systems.

Full text

PDF
539

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Almers W. Exocytosis. Annu Rev Physiol. 1990;52:607–624. doi: 10.1146/annurev.ph.52.030190.003135. [DOI] [PubMed] [Google Scholar]
  2. Augustine G. J., Charlton M. P. Calcium dependence of presynaptic calcium current and post-synaptic response at the squid giant synapse. J Physiol. 1986 Dec;381:619–640. doi: 10.1113/jphysiol.1986.sp016347. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Augustine G. J., Neher E. Calcium requirements for secretion in bovine chromaffin cells. J Physiol. 1992 May;450:247–271. doi: 10.1113/jphysiol.1992.sp019126. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Augustine G. J. Regulation of transmitter release at the squid giant synapse by presynaptic delayed rectifier potassium current. J Physiol. 1990 Dec;431:343–364. doi: 10.1113/jphysiol.1990.sp018333. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bittner M. A., Holz R. W. Kinetic analysis of secretion from permeabilized adrenal chromaffin cells reveals distinct components. J Biol Chem. 1992 Aug 15;267(23):16219–16225. [PubMed] [Google Scholar]
  6. Chad J. E., Eckert R. Calcium domains associated with individual channels can account for anomalous voltage relations of CA-dependent responses. Biophys J. 1984 May;45(5):993–999. doi: 10.1016/S0006-3495(84)84244-7. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. De Camilli P. Co-secretion of multiple signal molecules from endocrine cells via distinct exocytotic pathways. Trends Pharmacol Sci. 1991 Dec;12(12):446–448. doi: 10.1016/0165-6147(91)90631-2. [DOI] [PubMed] [Google Scholar]
  8. Fidler N., Fernandez J. M. Phase tracking: an improved phase detection technique for cell membrane capacitance measurements. Biophys J. 1989 Dec;56(6):1153–1162. doi: 10.1016/S0006-3495(89)82762-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Gainer H., Wolfe S. A., Jr, Obaid A. L., Salzberg B. M. Action potentials and frequency-dependent secretion in the mouse neurohypophysis. Neuroendocrinology. 1986;43(5):557–563. doi: 10.1159/000124582. [DOI] [PubMed] [Google Scholar]
  10. Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
  11. Hartzell H. C. Mechanisms of slow postsynaptic potentials. Nature. 1981 Jun 18;291(5816):539–544. doi: 10.1038/291539a0. [DOI] [PubMed] [Google Scholar]
  12. Heidelberger R., Heinemann C., Neher E., Matthews G. Calcium dependence of the rate of exocytosis in a synaptic terminal. Nature. 1994 Oct 6;371(6497):513–515. doi: 10.1038/371513a0. [DOI] [PubMed] [Google Scholar]
  13. Heinemann C., Chow R. H., Neher E., Zucker R. S. Kinetics of the secretory response in bovine chromaffin cells following flash photolysis of caged Ca2+. Biophys J. 1994 Dec;67(6):2546–2557. doi: 10.1016/S0006-3495(94)80744-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Jackson M. B., Konnerth A., Augustine G. J. Action potential broadening and frequency-dependent facilitation of calcium signals in pituitary nerve terminals. Proc Natl Acad Sci U S A. 1991 Jan 15;88(2):380–384. doi: 10.1073/pnas.88.2.380. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Jackson M. B. Passive current flow and morphology in the terminal arborizations of the posterior pituitary. J Neurophysiol. 1993 Mar;69(3):692–702. doi: 10.1152/jn.1993.69.3.692. [DOI] [PubMed] [Google Scholar]
  16. Lim N. F., Nowycky M. C., Bookman R. J. Direct measurement of exocytosis and calcium currents in single vertebrate nerve terminals. Nature. 1990 Mar 29;344(6265):449–451. doi: 10.1038/344449a0. [DOI] [PubMed] [Google Scholar]
  17. Lindau M., Neher E. Patch-clamp techniques for time-resolved capacitance measurements in single cells. Pflugers Arch. 1988 Feb;411(2):137–146. doi: 10.1007/BF00582306. [DOI] [PubMed] [Google Scholar]
  18. Monck J. R., Alvarez de Toledo G., Fernandez J. M. Tension in secretory granule membranes causes extensive membrane transfer through the exocytotic fusion pore. Proc Natl Acad Sci U S A. 1990 Oct;87(20):7804–7808. doi: 10.1073/pnas.87.20.7804. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Neher E., Marty A. Discrete changes of cell membrane capacitance observed under conditions of enhanced secretion in bovine adrenal chromaffin cells. Proc Natl Acad Sci U S A. 1982 Nov;79(21):6712–6716. doi: 10.1073/pnas.79.21.6712. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Neher E., Zucker R. S. Multiple calcium-dependent processes related to secretion in bovine chromaffin cells. Neuron. 1993 Jan;10(1):21–30. doi: 10.1016/0896-6273(93)90238-m. [DOI] [PubMed] [Google Scholar]
  21. Nordmann J. J., Artault J. C. Membrane retrieval following exocytosis in isolated neurosecretory nerve endings. Neuroscience. 1992 Jul;49(1):201–207. doi: 10.1016/0306-4522(92)90088-j. [DOI] [PubMed] [Google Scholar]
  22. Peng Y. Y., Zucker R. S. Release of LHRH is linearly related to the time integral of presynaptic Ca2+ elevation above a threshold level in bullfrog sympathetic ganglia. Neuron. 1993 Mar;10(3):465–473. doi: 10.1016/0896-6273(93)90334-n. [DOI] [PubMed] [Google Scholar]
  23. Rall W. Time constants and electrotonic length of membrane cylinders and neurons. Biophys J. 1969 Dec;9(12):1483–1508. doi: 10.1016/S0006-3495(69)86467-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Ryan T. A., Reuter H., Wendland B., Schweizer F. E., Tsien R. W., Smith S. J. The kinetics of synaptic vesicle recycling measured at single presynaptic boutons. Neuron. 1993 Oct;11(4):713–724. doi: 10.1016/0896-6273(93)90081-2. [DOI] [PubMed] [Google Scholar]
  25. Seward E. P., Chernevskaya N. I., Nowycky M. C. Exocytosis in peptidergic nerve terminals exhibits two calcium-sensitive phases during pulsatile calcium entry. J Neurosci. 1995 May;15(5 Pt 1):3390–3399. doi: 10.1523/JNEUROSCI.15-05-03390.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Stuenkel E. L. Regulation of intracellular calcium and calcium buffering properties of rat isolated neurohypophysial nerve endings. J Physiol. 1994 Dec 1;481(Pt 2):251–271. doi: 10.1113/jphysiol.1994.sp020436. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Thomas P., Lee A. K., Wong J. G., Almers W. A triggered mechanism retrieves membrane in seconds after Ca(2+)-stimulated exocytosis in single pituitary cells. J Cell Biol. 1994 Mar;124(5):667–675. doi: 10.1083/jcb.124.5.667. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Thomas P., Surprenant A., Almers W. Cytosolic Ca2+, exocytosis, and endocytosis in single melanotrophs of the rat pituitary. Neuron. 1990 Nov;5(5):723–733. doi: 10.1016/0896-6273(90)90226-6. [DOI] [PubMed] [Google Scholar]
  29. von Gersdorff H., Matthews G. Dynamics of synaptic vesicle fusion and membrane retrieval in synaptic terminals. Nature. 1994 Feb 24;367(6465):735–739. doi: 10.1038/367735a0. [DOI] [PubMed] [Google Scholar]
  30. von Gersdorff H., Matthews G. Inhibition of endocytosis by elevated internal calcium in a synaptic terminal. Nature. 1994 Aug 25;370(6491):652–655. doi: 10.1038/370652a0. [DOI] [PubMed] [Google Scholar]
  31. von Rüden L., Neher E. A Ca-dependent early step in the release of catecholamines from adrenal chromaffin cells. Science. 1993 Nov 12;262(5136):1061–1065. doi: 10.1126/science.8235626. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES