The Journal of Neurophysiology Vol. 80 No. 4 October 1998, pp. 1900-1910
Copyright ©1998 The American Physiological Society

Vasopressin-Induced Currents in Rat Neonatal Spinal Lateral Horn Neurons Are G-Protein Mediated and Involve Two Conductances

Miloslav Kolaj and Leo P. Renaud

Neuroscience, Loeb Research Institute, Ottawa Civic Hospital and University of Ottawa, Ottawa, Ontario K1Y 4E9, Canada

Kolaj, Miloslav and Leo P. Renaud. Vasopressin-induced currents in rat neonatal spinal lateral horn neurons are G-protein mediated and involve two conductances. J. Neurophysiol. 80: 1900-1910, 1998. Arginine vasopressin (AVP) receptors are expressed early in the developing spinal cord. To characterize AVP-induced conductances in lower thoracic sympathetic preganglionic (SPN) and other lateral horn neurons, we used patch-clamp recording techniques in neonatal (11-21 days) rat spinal cord slices. Most (90%) of 273 neurons, including all 68 SPNs, responded to AVP with membrane depolarization and/or a V₁ receptor-mediated, dose-dependent (0.01-1.0 µM) and tetrodotoxin (TTX)-resistant inward current. A role for G-proteins was indicated by persistence of this inward current after intracellular dialysis with GTP--S or GMP-PNP, its marked reduction with GDP--S, and significant reduction, but not abolition, after preincubation with pertussis toxin or in the presence of N-ethylmaleimide. Analysis of individual current-voltage (I-V) relationships in 57 cells indicated the presence of two different membrane conductances. In 21 cells, net AVP-induced currents reversed around 103 mV, reflecting reduction in one or more barium-sensitive potassium conductances; in 12 cells, net AVP-induced current reversed around 40 mV and was not significantly sensitive to several potassium channel blockers including barium, tetraethylammonium chloride (TEA), 4-aminopyridine (4AP), cesium, or glibenclamide, suggesting increase in a nonselective cationic conductance that was separate from I_h; in 24 cells where I-V lines shifted in parallel, AVP-induced inward currents were significantly greater and probably involved both conductances. These data indicate that SPNs and a majority of unidentified neonatal lateral horn neurons possess functional G-protein-coupled V₁-type vasopressin receptors. The wide distribution of AVP receptors in neonatal spinal lateral column cells suggests a role that may extend beyond involvement in regulation of autonomic nervous system function.

This article has been cited by other articles:

				M. Oz, K.-H. Yang, T. S. Shippenberg, L. P. Renaud, and M. J. O'Donovan Cholecystokinin B-Type Receptors Mediate a G-Protein-Dependent Depolarizing Action of Sulphated Cholecystokinin Ocatapeptide (CCK-8s) on Rodent Neonatal Spinal Ventral Horn Neurons J Neurophysiol, September 1, 2007; 98(3): 1108 - 1114. [Abstract] [Full Text] [PDF]

				R. Ogier, E. Tribollet, P. Suarez, and M. Raggenbass Identified motoneurons involved in sexual and eliminative functions in the rat are powerfully excited by vasopressin and tachykinins. J. Neurosci., October 18, 2006; 26(42): 10717 - 10726. [Abstract] [Full Text] [PDF]

				T. W. Bailey, Y.-H. Jin, M. W. Doyle, S. M. Smith, and M. C. Andresen Vasopressin inhibits glutamate release via two distinct modes in the brainstem. J. Neurosci., June 7, 2006; 26(23): 6131 - 6142. [Abstract] [Full Text] [PDF]

				L. Zhang, P. Doroshenko, X. Y. Cao, N. Irfan, E. Coderre, M. Kolaj, and L. P. Renaud Vasopressin induces depolarization and state-dependent firing patterns in rat thalamic paraventricular nucleus neurons in vitro Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2006; 290(5): R1226 - R1232. [Abstract] [Full Text] [PDF]

				M. Oz, K.-H. Yang, M. J. O'Donovan, and L. P. Renaud Presynaptic Angiotensin II AT1 Receptors Enhance Inhibitory and Excitatory Synaptic Neurotransmission to Motoneurons and Other Ventral Horn Neurons in Neonatal Rat Spinal Cord J Neurophysiol, August 1, 2005; 94(2): 1405 - 1412. [Abstract] [Full Text] [PDF]

				S. A. Pearson, A. Mouihate, Q. J. Pittman, and P. J. Whelan Peptidergic Activation of Locomotor Pattern Generators in the Neonatal Spinal Cord J. Neurosci., November 5, 2003; 23(31): 10154 - 10163. [Abstract] [Full Text] [PDF]

				M. Oz and L. P. Renaud Angiotensin AT1-Receptors Depolarize Neonatal Spinal Motoneurons and Other Ventral Horn Neurons Via Two Different Conductances J Neurophysiol, November 1, 2002; 88(5): 2857 - 2863. [Abstract] [Full Text] [PDF]

				M. Oz, M. Kolaj, and L. P. Renaud Electrophysiological Evidence for Vasopressin V1 Receptors on Neonatal Motoneurons, Premotor and Other Ventral Horn Neurons J Neurophysiol, September 1, 2001; 86(3): 1202 - 1210. [Abstract] [Full Text] [PDF]

				M.L.H.J. Hermes, J. M. Ruijter, A. Klop, R. M. Buijs, and L. P. Renaud Vasopressin Increases GABAergic Inhibition of Rat Hypothalamic Paraventricular Nucleus Neurons In Vitro J Neurophysiol, February 1, 2000; 83(2): 705 - 711. [Abstract] [Full Text] [PDF]