| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 269, Issue 6 1356-R1369, Copyright © 1995 by American Physiological Society
ARTICLES |
Y. W. Li, D. A. Bayliss and P. G. Guyenet
Department of Pharmacology, University of Virginia, Charlottesville 22908, USA.
Tyrosine-hydroxylase-immunoreactive (TH-ir) neurons (C1 cells) of the rostral ventrolateral medulla (RVL) control sympathetic tone and may be inhibited by the hypotensive drug clonidine. The present study seeks to describe some of the intrinsic properties of bulbospinal C1 cells and to establish whether they have alpha 2-adrenergic inhibitory "autoreceptors." RVL bulbospinal cells (retrogradely labeled with microbeads) were recorded in thin slices from 3- to 7-day-old rats with patch electrodes containing Lucifer yellow. Forty-two of eighty-nine cells were recovered histologically, and 69% were TH-ir. The properties of TH-ir cells could not be distinguished from those of the other bulbospinal cells. Most cells were spontaneously active (0.5-5 spikes/s). Blockade of fast postsynaptic potentials with kynurenic acid plus bicuculline plus strychnine or with a low-Ca(2+)-high-Mg2+ medium failed to reduce their firing rate. The membrane trajectory consisted of one of two patterns interconvertible by injections of depolarizing or hyperpolarizing current: 1) depolarizing ramps leading to spikes or 2) slow oscillations (tetrodotoxin resistant but absent at hyperpolarized potentials) leading to spikes or repolarization. The cells had Ca(2+)-dependent afterhyperpolarizations, large transient outward currents, and a hyperpolarization-activated inward current activated at potentials less than -65 mV, blocked by CsCl, and presumably responsible for a large inward rectification. Of 27 TH-ir cells, 21 had inhibitory responses to alpha 2-adrenergic agonists. These were blocked by idazoxan (n = 9). alpha 2-Agonists activated an inwardly rectifying potassium conductance (KIR). We confirm that bulbospinal C1 cells have intrinsic pacemaker properties and demonstrate that they have alpha 2-adrenergic receptors (autoreceptors) coupled to KIR channels.
This article has been cited by other articles:
|
|
 |
|
  J. H. Coote Landmarks in understanding the central nervous control of the cardiovascular system Exp Physiol, January 1, 2007; 92(1): 3 - 18. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Sun and W. M. Panneton The caudal pressor area of the rat: its precise location and projections to the ventrolateral medulla Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2002; 283(3): R768 - R778. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. M. Schreihofer and P. G. Guyenet Role of presympathetic C1 neurons in the sympatholytic and hypotensive effects of clonidine in rats Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2000; 279(5): R1753 - R1762. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Hayar and P. G. Guyenet Prototypical Imidazoline-1 Receptor Ligand Moxonidine Activates Alpha2-Adrenoceptors in Bulbospinal Neurons of the RVL J Neurophysiol, February 1, 2000; 83(2): 766 - 776. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Hayar and P. G. Guyenet alpha 2-Adrenoceptor-mediated presynaptic inhibition in bulbospinal neurons of rostral ventrolateral medulla Am J Physiol Heart Circ Physiol, September 1, 1999; 277(3): H1069 - H1080. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. R. Campos and R. M. McAllen Tonic drive to sympathetic premotor neurons of rostral ventrolateral medulla from caudal pressor area neurons Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1999; 276(4): R1209 - R1213. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Hayar and P. G. Guyenet Pre- and Postsynaptic Inhibitory Actions of Methionine-Enkephalin on Identified Bulbospinal Neurons of the Rat RVL J Neurophysiol, October 1, 1998; 80(4): 2003 - 2014. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. S. Hedrick, M. R. Dwinell, P. L. Janssen, J. Pizarro, and G. E. Bisgard Differential respiratory muscle recruitment induced by clonidine in awake goats J Appl Physiol, April 1, 1998; 84(4): 1198 - 1207. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Lipski, Y. Kawai, J. Qi, A. Comer, and J. Win Whole cell patch-clamp study of putative vasomotor neurons isolated from the rostral ventrolateral medulla Am J Physiol Regulatory Integrative Comp Physiol, April 1, 1998; 274(4): R1099 - R1110. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. G. Guyenet Is the hypotensive effect of clonidine and related drugs due to imidazoline binding sites? Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1997; 273(5): R1580 - R1584. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Huangfu and P. G. Guyenet Autoactivity of A5 neurons: role of subthreshold oscillations and persistent Na+ current Am J Physiol Heart Circ Physiol, November 1, 1997; 273(5): H2280 - H2289. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Huangfu and P. G. Guyenet alpha 2-Adrenergic autoreceptors in A5 and A6 neurons of neonate rats Am J Physiol Heart Circ Physiol, November 1, 1997; 273(5): H2290 - H2295. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
