HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Akaike, N Articles by Osipchuk, Y V Search for Related Content PubMed PubMed Citation Articles by Akaike, N Articles by Osipchuk, Y V

Department of Neurophysiology, Tohoku University, School of Medicine, Sendai, Japan.

1. Low-voltage-activated Ca2+ channels which produce a transient inward current were studied in neurones freshly isolated from the ventromedial hypothalamic region of the rat. Membrane currents were recorded using a suction-pipette technique which allows for internal perfusion under a single-electrode voltage clamp. A concentration-jump technique was also used for rapid drug application. 2. In most cells superfused with 10 mM-Ca2+, a transient inward Ca2+ current was evoked by a step depolarization to potentials more positive than -65 mV from a holding potential of -100 mV. Such a low-threshold Ca2+ current could easily be separated from a high-threshold, steady type of Ca2+ current by selecting the holding and test potential levels, as well as by resistance to the wash-out during cell dialysis. 3. Activation and inactivation processes of the low-threshold Ca2+ current were highly potential dependent at 20-22 degrees C. For a test potential change from -60 to +20 mV, the time to peak of the current decreased from 45 to 9 ms, and the time constant of the current decay decreased from 90 to 40 ms. The steady-state inactivation occurred at very negative potentials, reaching a 50% level at -93 mV. Recovery from inactivation showed a time constant between 2.63 and 0.94 s for a potential change from -80 to -120 mV. 4. The amplitude of the low-threshold Ca2+ current depended on the external Ca2+ concentration [( Ca2+]o), approaching saturation at 100 mM [Ca2+]o. Ba2+ substituted for Ca2+ reduced the current amplitude by 30-50% while Sr2+ produced no definite changes in the current amplitude. 5. The low-threshold Ca2+ current was blocked by various di- or trivalent cations in the sequence of La3+ greater than Zn2+ greater than Cd2+ greater than Ni2+ greater than Co2+. The corresponding apparent dissociation constants (KD) were 7 x 10(-7), 1 x 10(-4), 3 x 10(-4), 6 x 10(-4) and 3 x 10(-3) M. 6. Various organic Ca2+ antagonists were effective in blocking the low-threshold Ca2+ current in the following sequence: flunarizine greater than nicardipine greater than nifedipine greater than nimodipine greater than D600 (methoxyverapamil) greater than diltiazem. The corresponding KDs were 7 x 10(-7), 3.5 x 10(-6), 5 x 10(-6), 7 x 10(-6), 5 x 10(-5) and 7 x 10(-5) M. These Ca2+ antagonists induced a use-dependent decrease in the current amplitude.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				R. Berra-Romani, A. Mazzocco-Spezzia, M. V. Pulina, and V. A. Golovina Ca2+ handling is altered when arterial myocytes progress from a contractile to a proliferative phenotype in culture Am J Physiol Cell Physiol, September 1, 2008; 295(3): C779 - C790. [Abstract] [Full Text] [PDF]

				A. C. Yoon, V. Kathpalia, S. D'Silva, A. Cimenser, and S.-Y. Hua Determining Ca2+-sensor binding time and its variability in evoked neurotransmitter release J. Physiol., February 15, 2008; 586(4): 1005 - 1015. [Abstract] [Full Text] [PDF]

				B. Coste, M. Crest, and P. Delmas Pharmacological Dissection and Distribution of NaN/Nav1.9, T-type Ca2+ Currents, and Mechanically Activated Cation Currents in Different Populations of DRG Neurons J. Gen. Physiol., January 1, 2007; 129(1): 57 - 77. [Abstract] [Full Text] [PDF]

				C. D. Wood, T. Nishigaki, T. Furuta, S. A. Baba, and A. Darszon Real-time analysis of the role of Ca2+ in flagellar movement and motility in single sea urchin sperm J. Cell Biol., June 6, 2005; 169(5): 725 - 731. [Abstract] [Full Text] [PDF]

				S. Sedej, T. Tsujimoto, R. Zorec, and M. Rupnik Voltage-activated Ca2+ channels and their role in the endocrine function of the pituitary gland in newborn and adult mice J. Physiol., March 15, 2004; 555(3): 769 - 782. [Abstract] [Full Text] [PDF]

				B. R. Johnson, P. Kloppenburg, and R. M. Harris-Warrick Dopamine Modulation of Calcium Currents in Pyloric Neurons of the Lobster Stomatogastric Ganglion J Neurophysiol, August 1, 2003; 90(2): 631 - 643. [Abstract] [Full Text] [PDF]

				E. Perez-Reyes Molecular Physiology of Low-Voltage-Activated T-type Calcium Channels Physiol Rev, January 1, 2003; 83(1): 117 - 161. [Abstract] [Full Text] [PDF]

				M. Cataldi, E. Perez-Reyes, and R. W. Tsien Differences in Apparent Pore Sizes of Low and High Voltage-activated Ca2+ Channels J. Biol. Chem., November 22, 2002; 277(48): 45969 - 45976. [Abstract] [Full Text] [PDF]

				C. M. Santi, F. S. Cayabyab, K. G. Sutton, J. E. McRory, J. Mezeyova, K. S. Hamming, D. Parker, A. Stea, and T. P. Snutch Differential Inhibition of T-Type Calcium Channels by Neuroleptics J. Neurosci., January 15, 2002; 22(2): 396 - 403. [Abstract] [Full Text] [PDF]

				Y.-C. J. Lin and A. N. Spencer Calcium currents from jellyfish striated muscle cells: preservation of phenotype, characterisation of currents and channel localisation J. Exp. Biol., January 11, 2001; 204(21): 3717 - 3726. [Abstract] [Full Text] [PDF]

				Y.-P. Fan, E. M. Horn, and T. G. Waldrop Biophysical Characterization of Rat Caudal Hypothalamic Neurons: Calcium Channel Contribution to Excitability J Neurophysiol, December 1, 2000; 84(6): 2896 - 2903. [Abstract] [Full Text] [PDF]

				A. Bringmann, S. Schopf, and A. Reichenbach Developmental Regulation of Calcium Channel-Mediated Currents in Retinal Glial (Muller) Cells J Neurophysiol, December 1, 2000; 84(6): 2975 - 2983. [Abstract] [Full Text] [PDF]

				S.-I. Sekizawa, A. S. French, and P. H. Torkkeli Low-Voltage-Activated Calcium Current Does Not Regulate the Firing Behavior in Paired Mechanosensory Neurons With Different Adaptation Properties J Neurophysiol, February 1, 2000; 83(2): 746 - 753. [Abstract] [Full Text] [PDF]

				Z.-H. Pan Differential Expression of High- and Two Types of Low-Voltage-Activated Calcium Currents in Rod and Cone Bipolar Cells of the Rat Retina J Neurophysiol, January 1, 2000; 83(1): 513 - 527. [Abstract] [Full Text] [PDF]

				C. Arnoult, I. G. Kazam, P. E. Visconti, G. S. Kopf, M. Villaz, and H. M. Florman Control of the low voltage-activated calcium channel of mouse sperm by egg ZP3 and by membrane hyperpolarization during capacitation PNAS, June 8, 1999; 96(12): 6757 - 6762. [Abstract] [Full Text] [PDF]

				L. O. Goodwin, N. B. Leeds, D. Guzowski, I. R. Hurley, R. G. Pergolizzi, and S. Benoff Identification of structural elements of the testis-specific voltage dependent calcium channel that potentially regulate its biophysical properties Mol. Hum. Reprod., April 1, 1999; 5(4): 311 - 322. [Abstract] [Full Text] [PDF]

				A. Darszon, P. Labarca, T. Nishigaki, and F. Espinosa Ion Channels in Sperm Physiology Physiol Rev, April 1, 1999; 79(2): 481 - 510. [Abstract] [Full Text] [PDF]

				B. S. Huang and F. H. H. Leenen Sympathoinhibitory Effects of Central Nifedipine in Spontaneously Hypertensive Rats on High Versus Regular Sodium Intake Hypertension, January 1, 1999; 33(1): 32 - 35. [Abstract] [Full Text] [PDF]

				C. Arnoult, M. Villaz, and H. M. Florman Pharmacological Properties of the T-Type Ca2+ Current of Mouse Spermatogenic Cells Mol. Pharmacol., June 1, 1998; 53(6): 1104 - 1111. [Abstract] [Full Text]

				M. Wakamori, M. Strobeck, T. Niidome, T. Teramoto, K. Imoto, and Y. Mori Functional Characterization of Ion Permeation Pathway in the N-Type Ca2+ Channel J Neurophysiol, February 1, 1998; 79(2): 622 - 634. [Abstract] [Full Text] [PDF]

				D. Churchill and B. A. Macvicar Biophysical and Pharmacological Characterization of Voltage-Dependent Ca2+ Channels in Neurons Isolated From Rat Nucleus Accumbens J Neurophysiol, February 1, 1998; 79(2): 635 - 647. [Abstract] [Full Text] [PDF]

				S. M. Todorovic and C. J. Lingle Pharmacological Properties of T-Type Ca2+ Current in Adult Rat Sensory Neurons: Effects of Anticonvulsant and Anesthetic Agents J Neurophysiol, January 1, 1998; 79(1): 240 - 252. [Abstract] [Full Text] [PDF]

				G. Fischer, V. Mutel, G. Trube, P. Malherbe, J. N. C. Kew, E. Mohacsi, M. P. Heitz, and J. A. Kemp Ro 25-6981, a Highly Potent and Selective Blocker of N-Methyl-D-aspartate Receptors Containing the NR2B Subunit. Characterization in Vitro J. Pharmacol. Exp. Ther., December 1, 1997; 283(3): 1285 - 1292. [Abstract] [Full Text]

				M. Margeta-Mitrovic, J. J. Grigg, K. Koyano, Y. Nakajima, and S. Nakajima Neurotensin and Substance P Inhibit Low- and High-Voltage-Activated Ca2+ Channels in Cultured Newborn Rat Nucleus Basalis Neurons J Neurophysiol, September 1, 1997; 78(3): 1341 - 1352. [Abstract] [Full Text] [PDF]

				C.-J. Kim, J.-S. Rhee, and N. Akaike Modulation of High-Voltage Activated Ca2+ Channels in the Rat Periaqueductal Gray Neurons by µ-Type Opioid Agonist J Neurophysiol, March 1, 1997; 77(3): 1418 - 1424. [Abstract] [Full Text] [PDF]

				S. Fujii, K. Kameyama, M. Hosono, Y. Hayashi, and K. Kitamura Effect of Cilnidipine, a Novel Dihydropyridine Ca++-channel antagonist, on N-type Ca++ Channel in Rat Dorsal Root Ganglion Neurons J. Pharmacol. Exp. Ther., March 1, 1997; 280(3): 1184 - 1191. [Abstract] [Full Text]

				D. Mouginot, J.-L. Bossu, and B. H. Gahwiler Low-Threshold Ca2+ Currents in Dendritic Recordings from Purkinje Cells in Rat Cerebellar Slice Cultures J. Neurosci., January 1, 1997; 17(1): 160 - 170. [Abstract] [Full Text] [PDF]

				C. Arnoult, R. A. Cardullo, J. R. Lemos, and H. M. Florman Activation of mouse sperm T-type Ca2+ channels by adhesion to the egg zona pellucida PNAS, November 12, 1996; 93(23): 13004 - 13009. [Abstract] [Full Text] [PDF]

				A. Tottene, A. Moretti, and D. Pietrobon Functional Diversity of P-Type and R-Type Calcium Channels in Rat Cerebellar Neurons J. Neurosci., October 15, 1996; 16(20): 6353 - 6363. [Abstract] [Full Text] [PDF]

				E. de la Pena and E. Geijo-Barrientos Laminar Localization, Morphology, and Physiological Properties of Pyramidal Neurons that Have the Low-Threshold Calcium Current in the Guinea-Pig Medial Frontal Cortex J. Neurosci., September 1, 1996; 16(17): 5301 - 5311. [Abstract] [Full Text] [PDF]

				E. Bourinet, G. W. Zamponi, A. Stea, T. W. Soong, B. A. Lewis, L. P. Jones, D. T. Yue, and T. P. Snutch The alpha 1E Calcium Channel Exhibits Permeation Properties Similar to Low-Voltage-Activated Calcium Channels J. Neurosci., August 15, 1996; 16(16): 4983 - 4993. [Abstract] [Full Text] [PDF]

				P. H. Silverstone and D. G. Grahame-Smith Smithkline Beecham Prize for Young Psychopharmacologists: A review of the relationship between calcium channels and psychiatric disorders J Psychopharmacol, January 1, 1992; 6(4): 462 - 482. [Abstract] [PDF]

				J. E. McRory, C. M. Santi, K. S. C. Hamming, J. Mezeyova, K. G. Sutton, D. L. Baillie, A. Stea, and T. P. Snutch Molecular and Functional Characterization of a Family of Rat Brain T-type Calcium Channels J. Biol. Chem., February 2, 2001; 276(6): 3999 - 4011. [Abstract] [Full Text] [PDF]

				A. Rodriguez-Contreras, W. Nonner, and E. N. Yamoah Ca2+ transport properties and determinants of anomalous mole fraction effects of single voltage-gated Ca2+ channels in hair cells from bullfrog saccule J. Physiol., February 1, 2002; 538(3): 729 - 745. [Abstract] [Full Text] [PDF]