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. 1992 Jan;445:639–658. doi: 10.1113/jphysiol.1992.sp018944

Calcium current variation between acutely isolated adult rat dorsal root ganglion neurons of different size.

R S Scroggs 1, A P Fox 1
PMCID: PMC1180002  PMID: 1323671

Abstract

1. The distribution of pharmacologically and/or biophysically unique Ca2+ current subtypes was studied in different diameter rat dorsal root ganglion (DRG) neuron cell bodies. DRG cells which fell into three diameter ranges, small (20-27 microns), medium (33-38 microns) and large (45-51 microns), were studied. T-type Ca2+ current was defined as low-threshold, rapidly inactivating current evoked by a weak test depolarization (-50 mV) from negative holding potentials (-80 to -100 mV), and which was sensitive to changes in holding potential. L-type Ca2+ current was defined as peak high-threshold Ca2+ current evoked from a holding potential of -60 mV and sensitive to blockade by 2 microM-nimodipine. N-type Ca2+ current was defined as peak high-threshold Ca2+ current evoked from a holding potential of -60 mV and sensitive to blockade by 0.9 microM-omega-conotoxin GVIA. 2. T-type Ca2+ currents were observed in small and medium diameter, but not in large diameter, DRG cell bodies. Large diameter DRG cell bodies had a small amount of low-threshold Ca2+ current but this current did not inactivate and was insensitive to a change in holding potential from -80 to -90 mV, and thus did not appear to be conducted through T-type Ca2+ channels. The T-type Ca2+ currents observed in medium diameter DRG cell bodies were considerably larger in amplitude (1-6 nA) than those observed in small diameter DRG cell bodies (100 pA-1 nA). This difference could not be accounted for by the difference in membrane surface area of small versus medium diameter DRG cell bodies. 3. The T-type Ca2+ currents observed in medium diameter DRG cells were sensitive to blockade by amiloride. Amiloride (500 microM) blocked 79.4 +/- 0.9% (mean +/- S.E.M.) of T-type Ca2+ current amplitude in six medium diameter DRG cell bodies which were held at -80 mV and depolarized to -50 or -40 mV. Amiloride (500 microM) failed to block high-threshold current in five medium diameter DRG cell bodies, indicating that it was specific for T-type Ca2+ current in these cells. 4. The percentage of peak whole-cell L-type Ca2+ current was significantly larger in small diameter DRG cell bodies (52.9 +/- 4.7% of total whole-cell Ca2+ current) than in medium diameter DRG cell bodies (6.6 +/- 3.9% of total whole-cell Ca2+ current) or large diameter DRG cell bodies (19.4 +/- 5.7% of total whole-cell Ca2+ current).(ABSTRACT TRUNCATED AT 400 WORDS)

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Selected References

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  1. Aosaki T., Kasai H. Characterization of two kinds of high-voltage-activated Ca-channel currents in chick sensory neurons. Differential sensitivity to dihydropyridines and omega-conotoxin GVIA. Pflugers Arch. 1989 Jun;414(2):150–156. doi: 10.1007/BF00580957. [DOI] [PubMed] [Google Scholar]
  2. Billy A. J., Walters E. T. Long-term expansion and sensitization of mechanosensory receptive fields in Aplysia support an activity-dependent model of whole-cell sensory plasticity. J Neurosci. 1989 Apr;9(4):1254–1262. doi: 10.1523/JNEUROSCI.09-04-01254.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Boland L. M., Dingledine R. Multiple components of both transient and sustained barium currents in a rat dorsal root ganglion cell line. J Physiol. 1990 Jan;420:223–245. doi: 10.1113/jphysiol.1990.sp017909. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Cohen C. J., McCarthy R. T. Nimodipine block of calcium channels in rat anterior pituitary cells. J Physiol. 1987 Jun;387:195–225. doi: 10.1113/jphysiol.1987.sp016570. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Dolphin A. C., Forda S. R., Scott R. H. Calcium-dependent currents in cultured rat dorsal root ganglion neurones are inhibited by an adenosine analogue. J Physiol. 1986 Apr;373:47–61. doi: 10.1113/jphysiol.1986.sp016034. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Fedulova S. A., Kostyuk P. G., Veselovsky N. S. Ionic mechanisms of electrical excitability in rat sensory neurons during postnatal ontogenesis. Neuroscience. 1991;41(1):303–309. doi: 10.1016/0306-4522(91)90219-e. [DOI] [PubMed] [Google Scholar]
  7. Fox A. P., Nowycky M. C., Tsien R. W. Kinetic and pharmacological properties distinguishing three types of calcium currents in chick sensory neurones. J Physiol. 1987 Dec;394:149–172. doi: 10.1113/jphysiol.1987.sp016864. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Fox A. P., Nowycky M. C., Tsien R. W. Single-channel recordings of three types of calcium channels in chick sensory neurones. J Physiol. 1987 Dec;394:173–200. doi: 10.1113/jphysiol.1987.sp016865. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Harper A. A., Lawson S. N. Conduction velocity is related to morphological cell type in rat dorsal root ganglion neurones. J Physiol. 1985 Feb;359:31–46. doi: 10.1113/jphysiol.1985.sp015573. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Hirning L. D., Fox A. P., McCleskey E. W., Olivera B. M., Thayer S. A., Miller R. J., Tsien R. W. Dominant role of N-type Ca2+ channels in evoked release of norepinephrine from sympathetic neurons. Science. 1988 Jan 1;239(4835):57–61. doi: 10.1126/science.2447647. [DOI] [PubMed] [Google Scholar]
  11. Johnson D. A., Pilar G. The release of acetylcholine from post-ganglionic cell bodies in response to depolarization. J Physiol. 1980 Feb;299:605–619. doi: 10.1113/jphysiol.1980.sp013144. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Kayahara T., Takimoto T., Sakashita S. Synaptic junctions in the cat spinal ganglion. Brain Res. 1981 Jul 20;216(2):277–290. doi: 10.1016/0006-8993(81)90130-x. [DOI] [PubMed] [Google Scholar]
  13. Klein M., Kandel E. R. Presynaptic modulation of voltage-dependent Ca2+ current: mechanism for behavioral sensitization in Aplysia californica. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3512–3516. doi: 10.1073/pnas.75.7.3512. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Koerber H. R., Druzinsky R. E., Mendell L. M. Properties of somata of spinal dorsal root ganglion cells differ according to peripheral receptor innervated. J Neurophysiol. 1988 Nov;60(5):1584–1596. doi: 10.1152/jn.1988.60.5.1584. [DOI] [PubMed] [Google Scholar]
  15. Lester H. A., Snutch T. P., Leonard J. P., Nargeot J., Dascal N., Curtis B. M., Davidson N. Expression of mRNA encoding voltage-dependent Ca channels in Xenopus oocytes. Review and progress report. Ann N Y Acad Sci. 1989;560:174–182. doi: 10.1111/j.1749-6632.1989.tb24094.x. [DOI] [PubMed] [Google Scholar]
  16. Llinás R. R., Sugimori M., Cherksey B. Voltage-dependent calcium conductances in mammalian neurons. The P channel. Ann N Y Acad Sci. 1989;560:103–111. doi: 10.1111/j.1749-6632.1989.tb24084.x. [DOI] [PubMed] [Google Scholar]
  17. McCleskey E. W., Fox A. P., Feldman D. H., Cruz L. J., Olivera B. M., Tsien R. W., Yoshikami D. Omega-conotoxin: direct and persistent blockade of specific types of calcium channels in neurons but not muscle. Proc Natl Acad Sci U S A. 1987 Jun;84(12):4327–4331. doi: 10.1073/pnas.84.12.4327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Mogul D. J., Fox A. P. Evidence for multiple types of Ca2+ channels in acutely isolated hippocampal CA3 neurones of the guinea-pig. J Physiol. 1991 Feb;433:259–281. doi: 10.1113/jphysiol.1991.sp018425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Mudge A. W., Leeman S. E., Fischbach G. D. Enkephalin inhibits release of substance P from sensory neurons in culture and decreases action potential duration. Proc Natl Acad Sci U S A. 1979 Jan;76(1):526–530. doi: 10.1073/pnas.76.1.526. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Plummer M. R., Logothetis D. E., Hess P. Elementary properties and pharmacological sensitivities of calcium channels in mammalian peripheral neurons. Neuron. 1989 May;2(5):1453–1463. doi: 10.1016/0896-6273(89)90191-8. [DOI] [PubMed] [Google Scholar]
  21. Schroeder J. E., Fischbach P. S., McCleskey E. W. T-type calcium channels: heterogeneous expression in rat sensory neurons and selective modulation by phorbol esters. J Neurosci. 1990 Mar;10(3):947–951. doi: 10.1523/JNEUROSCI.10-03-00947.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Scroggs R. S., Fox A. P. Distribution of dihydropyridine and omega-conotoxin-sensitive calcium currents in acutely isolated rat and frog sensory neuron somata: diameter-dependent L channel expression in frog. J Neurosci. 1991 May;11(5):1334–1346. doi: 10.1523/JNEUROSCI.11-05-01334.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Suetake K., Kojima H., Inanaga K., Koketsu K. Catecholamine is released from non-synaptic cell-soma membrane: histochemical evidence in bullfrog sympathetic ganglion cells. Brain Res. 1981 Feb 2;205(2):436–440. doi: 10.1016/0006-8993(81)90357-7. [DOI] [PubMed] [Google Scholar]
  24. Tang C. M., Presser F., Morad M. Amiloride selectively blocks the low threshold (T) calcium channel. Science. 1988 Apr 8;240(4849):213–215. doi: 10.1126/science.2451291. [DOI] [PubMed] [Google Scholar]
  25. Todorović S., Anderson E. G. 5-HT2 and 5-HT3 receptors mediate two distinct depolarizing responses in rat dorsal root ganglion neurons. Brain Res. 1990 Mar 12;511(1):71–79. doi: 10.1016/0006-8993(90)90226-2. [DOI] [PubMed] [Google Scholar]
  26. White G., Lovinger D. M., Weight F. F. Transient low-threshold Ca2+ current triggers burst firing through an afterdepolarizing potential in an adult mammalian neuron. Proc Natl Acad Sci U S A. 1989 Sep;86(17):6802–6806. doi: 10.1073/pnas.86.17.6802. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Yaksh T. L., Hammond D. L. Peripheral and central substrates involved in the rostrad transmission of nociceptive information. Pain. 1982 May;13(1):1–85. doi: 10.1016/0304-3959(82)90067-7. [DOI] [PubMed] [Google Scholar]

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