Abstract
Cell-attached patch recordings were used to study calcium channels on the dendritic membrane of rat cerebellar Purkinje cells maintained in culture. Experiments were performed with isotonic BaCl2 (110 mM) in the pipette and isotonic potassium gluconate in the bath to zero the cell membrane potential. Two distinct types of voltage-activated calcium channels were identified. The first one had a small conductance (9 pS), was activated at a low threshold (≃ −50 mV) and could be inactivated by holding the membrane potential at −30 mV. This channel had the same characteristics as the T channel described in other neuronal preparations. The second type of Ca channel activated at a high threshold (−30 or +10 mV depending on whether BAY K 8644 was added or not to the pipette solution) and was still activatable even when the membrane was held at −40 mV. In the presence of BAY K 8644 this channel had a conductance of 21 pS with long openings. All these characteristics are similar to those of the S (L) Ca channel described in many preparations. The present study is in agreement with our previous experiments on Purkinje dendrites, where we identified low and high threshold Ca currents using the whole-cell configuration. Up to now, no channel corresponding to the N current has been observed but we cannot exclude us presence.
References
Bossu J-L, Dupont J-L, Feltz A (1989) Calcium currents in rat cerebellar Purkinje cells maintained in culture. Neuroscience (in press).
Carbone E, Lux HD (1984) A low voltage-activated, fully inactivating Ca channel in vertebrate sensory neurones. Nature 310: 501–502.
Coulombe A, Lefevre I (1988) Divalent cation permeable channels at negative membrane potentials in rat cardiac myocytes. J Physiol (Lond) 406: 232P.
Gray R, Johnston D (1987) Noradrenaline and β-adrenoceptor agonists increase activity of voltage-dependent calcium channels in hippocampal neurons. Nature (Lond) 327: 620–622.
Kostyuk PG, Shuba YM, Savchenko (1988) Three types of calcium channels in the membrane of mouse sensory neurons. Pflügers Arch 411: 661–669.
Llinas R, Sugimori M (1980) Electrophysiological properties of in vitro Purkinje cell dendrites in mammalian cerebellar slices. J Physiol (Lond) 305: 197–213.
Nowycky MC, Fox AP, Tsien VR (1989) Three types of neuronal calcium channel with different calcium agonist sensitivity. Nature (Lond) 316: 440–443.
Rosenberg RL, Hess P, Tsien RW (1988) L-type channels and calcium-permeable channels open at negative membrane potentials. J Gen Physiol 92: 27–54.
Tsien RW, Lipscombe D, Madison DV, Bley KR, Fox AP (1988) Multiple types of neuronal calcium channels and their selective modulation. Trends in Neurosci 11: 431–437.
Author information
Authors and Affiliations
Additional information
Present Andress: Centre CNRS-INSERM de Pharmacologie-Endocrinologie, rue de la Cardonille, B.P. 5055, 34033 Montpellier, France
Rights and permissions
About this article
Cite this article
Bossu, J.L., Fagni, L. & Feltz, A. Voltage-activated calcium channels in rat Purkinje cells maintained in culture. Pflugers Arch. 414, 92–94 (1989). https://doi.org/10.1007/BF00585632
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00585632