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Pflügers Archiv

, Volume 430, Issue 1, pp 44–54 | Cite as

Metabolic inhibition and low internal ATP activate K-ATP channels in rat dopaminergic substantia nigra neurones

  • Jochen Röper
  • Frances M. Ashcroft
Original Article Molecular and Cellular Physiology

Abstract

The patch-clamp technique was used to study whole-cell currents of acutely dissociated rat substantia nigra (SN) neurones. In perforated-patch current-clamp recordings, inhibition of mitochondrial metabolism by rotenone (5 μM) produced a hyperpolarisation and inhibited electrical activity. These effects were reversed by the sulphonylureas tolbutamide (0.5 mM) or glibenclamide (0.5 μM). Under voltageclamp conditions, rotenone induced a timeand voltage-independent K+ current which was selectively blocked by sulphonylureas. The glibenclamide-sensitive current reversed at −81.7±2.7 mV (n=5) and showed marked inward rectification. Intracellular dialysis with 0.3 mM adenosine 5′-triphosphate (ATP), but not 2 mM or 5 mM ATP, in standard whole-cell recordings also resulted in activation of a sulphonylurea-sensitive K+ current with similar properties (reversal potential, −81.9±2.5 mV, n=5). The close similarity in the properties of the ATP-sensitive K+ current observed in whole-cell recordings and the K+ current activated by metabolic inhibition in perforated-patch recordings suggest that they both result from activation of the same type of ATP-sensitive K+ channel. Sulphonylureas had no effect on electrical activity or membrane currents in the absence of rotenone in perforated-patch recordings, or in cells dialysed with 5 mM ATP, indicating that in SN neurones these drugs are selective for the ATP-sensitive K+ current.

Key words

Substantia nigra ATP-sensitive K+ channe Sulphonylurea Glibenclamide Tolbutamide 

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References

  1. 1.
    Amoroso S, Schmid-Antomarchi H, Fosset M, Lazdunski M (1990) Glucose, sulphonylureas, and neurotransmitter release: role of ATP-sensitive K channels. Science 247:852–854Google Scholar
  2. 2.
    Ashcroft SJH, Ashcroft FM (1990) Properties and Functions of ATP-sensitive K-channels. Cell Signal 2:197–214Google Scholar
  3. 3.
    Ashcroft SJH, Ashcroft FM (1992) The sulphonylurea receptor. Biochim Biophys Acta 1175:45–59Google Scholar
  4. 4.
    Ashford MLJ, Boden PR, Treherne JM (1990) Glucoseinduced excitation of hypothalamic neurones is mediated by ATP-sensitive K-channels. Pflügers Arch 415:479–483Google Scholar
  5. 5.
    Ben-Ari Y (1990) Galanin and glibenclamide modulate the anoxic release of glutamate in rat CA3 hippocampal neurones. Eur J Neurosci 2:62–68Google Scholar
  6. 6.
    Björklund A (1983) Fluorescence histochemistry of biogenic monoamines. In: Björklund A, Hökfelt T (eds) Handbook of chemical neuroanatomy, Vol 1. Elsevier, Amsterdam, pp 50–112Google Scholar
  7. 7.
    Cardozo DL (1993) Electrophysiological properties of midbrain dopaminergic neurones from postnatal rat in primary culture. Neuroscience 56:409–421Google Scholar
  8. 8.
    Crépel V, Krnjevic K, Ben-Ari Y (1993) Sulphonylureas reduce the slowly inactivating D-type outward current in rat hippocampal neurons. J Physiol (Lond) 466:39–56Google Scholar
  9. 9.
    Fujiwara N, Higashi H, Shimoji K, Yoshimura M (1987) Effects of hypoxia on rat hippocampal neurones in vitro. J Physiol (Lond) 384:131–151Google Scholar
  10. 10.
    Grace AA, Bunney BS (1984) The control of firing pattern in nigral neurones: burst firing. J Neurosci 4:2877–2890Google Scholar
  11. 11.
    Grace AA, Onn S-P (1989) Morphology and electrophysiological properties of immunocytochemically identified rat dopamine neurones recorded in vitro. J Neurosci 9:3463–3481Google Scholar
  12. 12.
    Grigg JJ, Anderson EG (1989) Glucose and sulphonylureas modify different phases of the membrane potential change during hypoxia in rat hippocampal slices. Brain Res 489:302–310Google Scholar
  13. 13.
    Hainsworth AH, Röper J, Kapoor R, Ashcroft FM (1991) Identification and electrophysiology of isolated pars compacta neurones from guinea-pig substantia nigra. Neuroscience 43:81–93Google Scholar
  14. 14.
    Hamill OP, Marty A, Neher E, Sakmann B, Sigworth FJ (1981) Improved patch-clamp techniques for high-resolution current recording from cell and cell-free membrane patches. Pflügers Arch 391:85–100Google Scholar
  15. 15.
    Hicks GA 1994 Adenosine 5′-triphosphate-sensitive potassium channels in the rat substantia nigra. D.Phil. thesis, University of CambridgeGoogle Scholar
  16. 16.
    Kass IS, Lipton P (1982) Mechanism involved in irreversible anoxic damage to the in vitro rat hippocampal slice. J Physiol (Lond) 332:459–472Google Scholar
  17. 17.
    Lacey MG, Mercuri NB, North RA (1988) On the potassium conductance increase acivated by GABA-B and dopamine D2 receptors in rat substantia nigra neurones. J Physiol (Lond) 401:437–453Google Scholar
  18. 18.
    Lacey MG, Mercuri NB, North RA (1989) Two cell types in rat substantia nigra zona compacta distinguished by membrane properties and the action of dopamine and opioids. J Neurosci 9:1233–1241Google Scholar
  19. 19.
    Leblond J, Krnjevic K (1989) Changes in membrane currents of hippocampal neurones evoked by brief anoxia. J Neurophysiol 62:1–14Google Scholar
  20. 20.
    Lee K, Ozanne S, Hales CN, Ashford MLJ (1994) Mg-dependent inhibition of KATP by sulphonylureas in CRI-G1 insulin-secreting cells. Br J Pharmacol 111:632–640Google Scholar
  21. 21.
    Luhmann HJ, Heinemann U (1992) Hypoxia-induced functional alterations in adult rat neocortex. J Neurophysiol 67:798–811Google Scholar
  22. 22.
    Mann VM, Cooper JM, Krige D, Daniel SE, Schapira AHV, Marsden CD (1992) Brain, skeletal muscle and platelet homogenate mitochondrial function in Parkinson's Disease. Brain 115:333–342Google Scholar
  23. 23.
    Mourre C, Ben-Ari Y, Bernadi H, Fosset M, Lazdunski M (1989) Antidiabetic sulphonylureas: localisation of binding sites in the brain and effects on the hyperpolarization induced by anoxia in hippocampal slices. Brain Res 486:159–164Google Scholar
  24. 24.
    Mourre C, Widmann C, Lazdunski M (1990) Sulphonylurea binding sites associated with ATP-regulated K channels in the central nervous system: autoradiographic analysis of their distribution and ontogeneis, and of their localisation in mutant mice cerebellum. Brain Res 519:29–43Google Scholar
  25. 25.
    Murphy KPSJ, Greenfield SA (1992) Neuronal selectivity of ATP-sensitive potassium channels in the guinea-pig substantia nigra revealed by differential responses to anoxia. J Physiol (Lond) 453:167–183Google Scholar
  26. 26.
    Nedergaard S, Greenfield SA (1992) Sub-populations of pars compacta neurones in the substantia nigra: the significance of qualitatively and quantitatively distinct conductances. Neuroscience 48:423–437Google Scholar
  27. 27.
    Ohno-Shosaku T, Yamamoto C (1992) Identification of an ATP-sensitive K channel in rat cultured cortical neurones. Pflügers Arch 422:260–266Google Scholar
  28. 28.
    Röper J, Ashcroft FM 1993 atReduced internal ATP concentrations and mitochondrial inhibition activate K-ATP channels in isolated dopaminergic substantia nigra neurones from rat (abstract). J Physiol (Lond) 473:32PGoogle Scholar
  29. 29.
    Röper J, Hainsworth AH, Ashcroft FM 1990 ATP-sensitive K channels in guinea-pig isolated substantia nigra neurones are modulated by cellular metabolism (abstract). J Physiol (Lond) 430:130PGoogle Scholar
  30. 30.
    Rorsman P, Trube G (1985) Glucose dependent K+ channels in pancreatic β-cells are regulated by intracellular ATP. Pflügers Arch 405:305–309Google Scholar
  31. 31.
    Schwanstecher C, Panten U (1993) Tolbutamide and diaxozidesensitive K+ channel in neurons of substantia nigra pars reticulata. Naunyn Schmeidebergs Arch Pharmacol 348:113–117Google Scholar
  32. 32.
    Siesjö BK (1978) Brain energy metabolism. Wiley, ChichesterGoogle Scholar
  33. 33.
    Treherne JM, Ashford MLJ (1991) The regional distribution of sulphonylurea binding sites in rat brain. Neuroscience 40:523–531Google Scholar
  34. 34.
    Vyas I, Heikkila RE, Nicklas WJ (1986) Studies on the neurotoxicity of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine: inhibition of NADH-linked substrate oxidation by its metabolite 1-methyl-4-phenylpyridinium. J Neurochem 46:1501–1507Google Scholar
  35. 35.
    Williams B 1993 Modulation of the ATP-sensitive K-channel in pancreatic β-cells. D.Phil. thesis, University of OxfordGoogle Scholar
  36. 36.
    Yung WH, Häusser MA, Jack JJB (1991) Electrophysiology of dopaminergic and non-dopaminergic neurones of the guineapig substantia nigra pars compacta in vitro. J Physiol (Lond) 436:643–667Google Scholar
  37. 37.
    Zini S, Tremblay E, Roisin M, Ben-Ari Y (1991) Two binding sites for [3H] glibenclamide in the rat brain. Brain Res 542:151–154Google Scholar
  38. 38.
    Zünckler BJ, Lenzen S, Männer K, Panten U, Trube G (1988) Concentration-dependent effects of tolbutamide, meglitinide, glibenclamide and diazoxide on ATP-regulated K+ currents in pancreatic β-cells. Naunyn Schmeidebergs Arch Pharmacol 337:225–230Google Scholar

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • Jochen Röper
    • 1
  • Frances M. Ashcroft
    • 1
  1. 1.University Laboratory of PhysiologyOxfordUK

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