Journal of Neurophysiology, Vol 55, Issue 3 527-539, Copyright © 1986 by APS

ARTICLES

Na+ and Ca2+ currents of acutely isolated adult rat nodose ganglion cells

S. R. Ikeda, G. G. Schofield and F. F. Weight

The electrical properties of nodose ganglion cells acutely isolated from adult rats were studied using the whole-cell patch-clamp recording method. Current-clamp recordings revealed a mean resting membrane potential of -54.3 mV and an input resistance of 527 M omega. Depolarizing current steps evoked action potentials with the following properties (mean): amplitude 111 mV, threshold -36 mV, and rate of rise 117 V/s. Two types of action potentials were observed, short and long duration. These properties, with the exception of input resistance (527 M omega cf. 50 M omega), are similar to those reported previously using intracellular recording methods in intact nodose ganglia (11, 20, 28). Brief application of 10 microM 5-hydroxytryptamine resulted in a rapid depolarization and burst of action potentials in the majority of cells. With voltage-clamp recording, step depolarizations to potentials positive to -10 mV elicited a transient inward current that was followed by a sustained outward current. Inward Na+ current was isolated by ion substitution and pharmacological agents. Two types of Na+ current were observed. One current was completely abolished by 3-15 microM tetrodotoxin (TTX), had a rapid time course, activated over the potential range -60 to -10 mV, and attained half-maximal conductance at -30 mV. The other current persisted in the presence of 15 microM TTX, had a slower time course, activated over the potential range -30 to 0 mV, and attained half-maximal conductance at -15 mV. In addition, 500 microM Cd2+ and 5.0 mM Co2+ reduced the TTX-insensitive current to 53 and 42% of control, respectively. Inward Ca2+ current was isolated by ion substitution and pharmacological agents and was identified by a dependence on external Ca2+. Cd2+ (500 microM) and Co2+ (5 mM) reduced the maximal inward current to 5 and 20% of control, respectively. When Ba2+ was substituted for Ca2+ as the charge carrier, the maximal inward current increased to 175% of control. Some cells had two Ca2+ current components, an inactivating component that activated near -60 mV and a large sustained current that activated near -40 mV. The initial inactivating current appeared as a "hump" on the current-voltage (I-V) curve over the potential range of -60 to -30 mV. The results indicate that, following isolation of these adult mammalian neurons, the membrane surfaces are sufficiently clean to allow patch-clamp recording.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				G. G. Schofield, H. L. Puhl 3rd, and S. R. Ikeda Properties of Wild-Type and Fluorescent Protein-Tagged Mouse Tetrodotoxin-Resistant Sodium Channel (NaV1.8) Heterologously Expressed in Rat Sympathetic Neurons J Neurophysiol, April 1, 2008; 99(4): 1917 - 1927. [Abstract] [Full Text] [PDF]

				T. N. Doan, K. Stephans, A. N. Ramirez, P. A. Glazebrook, M. C. Andresen, and D. L. Kunze Differential Distribution and Function of Hyperpolarization-Activated Channels in Sensory Neurons and Mechanosensitive Fibers J. Neurosci., March 31, 2004; 24(13): 3335 - 3343. [Abstract] [Full Text] [PDF]

				F. A. Abdulla and P. A. Smith Changes in Na+ Channel Currents of Rat Dorsal Root Ganglion Neurons Following Axotomy and Axotomy-Induced Autotomy J Neurophysiol, November 1, 2002; 88(5): 2518 - 2529. [Abstract] [Full Text] [PDF]

				K. Kwong and L.-Y. Lee PGE2 sensitizes cultured pulmonary vagal sensory neurons to chemical and electrical stimuli J Appl Physiol, October 1, 2002; 93(4): 1419 - 1428. [Abstract] [Full Text] [PDF]

				T. O. Lankisch, Y. Tsunoda, Y. Lu, and C. Owyang Characterization of CCKA receptor affinity states and Ca2+ signal transduction in vagal nodose ganglia Am J Physiol Gastrointest Liver Physiol, June 1, 2002; 282(6): G1002 - G1008. [Abstract] [Full Text] [PDF]

				E. COOPER Nicotinic Acetylcholine Receptors on Vagal Afferent Neurons Ann. N.Y. Acad. Sci., June 1, 2001; 940(1): 110 - 118. [Abstract] [Full Text] [PDF]

				F. A. Abdulla and P. A. Smith Axotomy- and Autotomy-Induced Changes in the Excitability of Rat Dorsal Root Ganglion Neurons J Neurophysiol, February 1, 2001; 85(2): 630 - 643. [Abstract] [Full Text] [PDF]

				F. A. Abdulla and P. A. Smith Axotomy- and Autotomy-Induced Changes in Ca2+and K+ Channel Currents of Rat Dorsal Root Ganglion Neurons J Neurophysiol, February 1, 2001; 85(2): 644 - 658. [Abstract] [Full Text] [PDF]

				E. Lancaster, E. J. Oh, and D. Weinreich Vagotomy Decreases Excitability in Primary Vagal Afferent Somata J Neurophysiol, January 1, 2001; 85(1): 247 - 253. [Abstract] [Full Text] [PDF]

				A. M. Strassman and S. A. Raymond Electrophysiological Evidence for Tetrodotoxin-Resistant Sodium Channels in Slowly Conducting Dural Sensory Fibers J Neurophysiol, February 1, 1999; 81(2): 413 - 424. [Abstract] [Full Text] [PDF]

				G. Jeglitsch, K. Rein, D. G. Baden, and D. J. Adams Brevetoxin-3 (PbTx-3) and Its Derivatives Modulate Single Tetrodotoxin-Sensitive Sodium Channels in Rat Sensory Neurons J. Pharmacol. Exp. Ther., February 1, 1998; 284(2): 516 - 525. [Abstract] [Full Text]

				J. H. Schild and D. L. Kunze Experimental and Modeling Study of Na+ Current Heterogeneity in Rat Nodose Neurons and Its Impact on Neuronal Discharge J Neurophysiol, December 1, 1997; 78(6): 3198 - 3209. [Abstract] [Full Text] [PDF]

				M. J. Sullivan, R. V. Sharma, R. E. Wachtel, M. W. Chapleau, L. J. Waite, R. C. Bhalla, and F. M. Abboud Non–Voltage-Gated Ca2+ Influx Through Mechanosensitive Ion Channels in Aortic Baroreceptor Neurons Circ. Res., June 19, 1997; 80(6): 861 - 867. [Abstract] [Full Text]

				L. Sangameswaran, S. G. Delgado, L. M. Fish, B. D. Koch, L. B. Jakeman, G. R. Stewart, P. Sze, J. C. Hunter, R. M. Eglen, and R. C. Herman Structure and Function of a Novel Voltage-gated, Tetrodotoxin-resistant Sodium Channel Specific to Sensory Neurons J. Biol. Chem., March 15, 1996; 271(11): 5953 - 5956. [Abstract] [Full Text] [PDF]

				M. W. Chapleau, J. T. Cunningham, M. J. Sullivan, R. E. Wachtel, and F. M. Abboud Structural Versus Functional Modulation of the Arterial Baroreflex Hypertension, August 1, 1995; 26(2): 341 - 347. [Abstract] [Full Text]

				X. Ma, M. W. Chapleau, C. A. Whiteis, F. M. Abboud, and K. Bielefeldt Angiotensin Selectively Activates a Subpopulation of Postganglionic Sympathetic Neurons in Mice Circ. Res., April 27, 2001; 88(8): 787 - 793. [Abstract] [Full Text] [PDF]