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. 1993 Oct;470:23–33. doi: 10.1113/jphysiol.1993.sp019844

Calcium currents and calcium-dependent potassium currents in mammalian medullary respiratory neurones.

D W Richter 1, J Champagnat 1, T Jacquin 1, R Benacka 1
PMCID: PMC1143903  PMID: 8308727

Abstract

1. Respiratory neurons of mammals are rhythmically active because their membrane potential fluctuates periodically over a voltage range of -70 to -55 mV. These respiratory drive potentials lead to periodic discharges of bursts of action potentials lasting for 1-2 s. The neuronal processes stabilizing this rhythmic activity involve excitatory and inhibitory synaptic processes that interact with specific membrane properties of the postsynaptic neurones. In the present experiments, performed on dorsal and ventral groups of respiratory neurones under in vivo and in vitro conditions, we verified the modulating feature of such intrinsic neuronal properties. 2. Intrinsic neuronal properties involve Ca2+ mechanisms that lead to intracellular Ca2+ accumulation, and consequently to activation of Ca(2+)-dependent K+ currents. 3. Blockade of intracellular Ca2+ accumulation significantly changed the amplitude and pattern of respiratory drive potentials, and blocked initial hyperpolarizing shifts of the membrane potential following each period of synaptic activation. 4. The data demonstrate that postsynaptic activities and action potential discharges activate low and high voltage-activated Ca2+ currents leading to intracellular Ca2+ accumulation and to activation of Ca(2+)-dependent K+ currents that significantly modulate the voltage response of medullary respiratory neurones to on-going synaptic activation. These intrinsic membrane properties also seem to be involved in the processes controlling termination of rhythmic burst discharges.

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Selected References

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

  1. Anderson C. S., MacKinnon R., Smith C., Miller C. Charybdotoxin block of single Ca2+-activated K+ channels. Effects of channel gating, voltage, and ionic strength. J Gen Physiol. 1988 Mar;91(3):317–333. doi: 10.1085/jgp.91.3.317. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Carbone E., Lux H. D. Kinetics and selectivity of a low-voltage-activated calcium current in chick and rat sensory neurones. J Physiol. 1987 May;386:547–570. doi: 10.1113/jphysiol.1987.sp016551. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Champagnat J., Jacquin T., Richter D. W. Voltage-dependent currents in neurones of the nuclei of the solitary tract of rat brainstem slices. Pflugers Arch. 1986 Apr;406(4):372–379. doi: 10.1007/BF00590939. [DOI] [PubMed] [Google Scholar]
  4. Connor J. A., Stevens C. F. Voltage clamp studies of a transient outward membrane current in gastropod neural somata. J Physiol. 1971 Feb;213(1):21–30. doi: 10.1113/jphysiol.1971.sp009365. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Feldman J. L., Windhorst U., Anders K., Richter D. W. Synaptic interaction between medullary respiratory neurones during apneusis induced by NMDA-receptor blockade in cat. J Physiol. 1992 May;450:303–323. doi: 10.1113/jphysiol.1992.sp019128. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Hounsgaard J., Hultborn H., Kiehn O. Transmitter-controlled properties of alpha-motoneurones causing long-lasting motor discharge to brief excitatory inputs. Prog Brain Res. 1986;64:39–49. doi: 10.1016/S0079-6123(08)63398-1. [DOI] [PubMed] [Google Scholar]
  7. Keller B. U., Hollmann M., Heinemann S., Konnerth A. Calcium influx through subunits GluR1/GluR3 of kainate/AMPA receptor channels is regulated by cAMP dependent protein kinase. EMBO J. 1992 Mar;11(3):891–896. doi: 10.1002/j.1460-2075.1992.tb05127.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Mifflin S., Richter D. W. The effects of QX-314 on medullary respiratory neurones. Brain Res. 1987 Sep 8;420(1):22–31. doi: 10.1016/0006-8993(87)90235-6. [DOI] [PubMed] [Google Scholar]
  9. Pierrefiche O., Foutz A. S., Champagnat J., Denavit-Saubié M. The bulbar network of respiratory neurons during apneusis induced by a blockade of NMDA receptors. Exp Brain Res. 1992;89(3):623–639. doi: 10.1007/BF00229887. [DOI] [PubMed] [Google Scholar]
  10. Richter D. W., Ballanyi K., Schwarzacher S. Mechanisms of respiratory rhythm generation. Curr Opin Neurobiol. 1992 Dec;2(6):788–793. doi: 10.1016/0959-4388(92)90135-8. [DOI] [PubMed] [Google Scholar]
  11. Richter D. W. Generation and maintenance of the respiratory rhythm. J Exp Biol. 1982 Oct;100:93–107. doi: 10.1242/jeb.100.1.93. [DOI] [PubMed] [Google Scholar]
  12. Takeda R., Haji A. Mechanisms underlying post-inspiratory depolarization in post-inspiratory neurons of the cat. Neurosci Lett. 1993 Feb 5;150(1):1–4. doi: 10.1016/0304-3940(93)90093-z. [DOI] [PubMed] [Google Scholar]
  13. Tsien R. W., Lipscombe D., Madison D. V., Bley K. R., Fox A. P. Multiple types of neuronal calcium channels and their selective modulation. Trends Neurosci. 1988 Oct;11(10):431–438. doi: 10.1016/0166-2236(88)90194-4. [DOI] [PubMed] [Google Scholar]

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