| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Pediatrics, University of North Carolina, Chapel Hill 27599-7220.
1. Postsynaptic potentials evoked by electrical stimulation of superior laryngeal nerve (SLN) were recorded during SLN-induced apnoea from the respiratory neurones of the ventral respiratory group (VRG) in pentobarbitone-anaesthetized, vagotomized and artificially ventilated newborn piglets (n = 14, 4-7 days old). All recorded inspiratory (n = 10), post-inspiratory (n = 10) and expiratory (n = 20) neurones had a triphasic pattern of membrane potential and were identified for their projections to the spinal cord or cervical vagus nerve. 2. During long-lasting apnoea, induced by SLN stimulation, the membrane potential trajectory of each type of recorded neurone was held at the level corresponding approximately to the membrane potential reached during stage I of expiration. Compound postsynaptic potentials evoked in most respiratory-related neurones had an early short-lasting and a late long-lasting component. 3. Postsynaptic potentials in four out of seven inspiratory neurones, in which postsynaptic potentials were well demonstrated, were characterized by an early depolarization followed by long-lasting hyperpolarization. In three other inspiratory neurones only late hyperpolarization was present. The reversal of the late hyperpolarization by intracellular chloride injection was achieved to a different degree in the early and late portions of late hyperpolarization. 4. Postsynaptic potentials evoked in expiratory neurones were studied in sixteen neurones and displayed two patterns: early hyperpolarization followed by long-lasting hyperpolarization (n = 7, six were not antidromically activated after spinal cord stimulation) or early hyperpolarization followed by late depolarization (n = 9, eight projected to the spinal cord). The early hyperpolarization was readily reversed by chloride injection. The late hyperpolarization was more difficult to reverse and usually the reversal was not completed. 5. Postsynaptic potentials evoked in post-inspiratory neurones showed a pattern of two consecutive phases of depolarization. 6. The present study revealed that during long-lasting apnoea evoked by SLN stimulation each category of VRG respiratory neurones received a temporally synchronized combination of an initial fast input derived reflexly from laryngeal afferents, and of late inputs representing involvement of the whole respiratory network in the response.
This article has been cited by other articles:
|
|
 |
|
  L. Xia, T. Damon, M. M. Niblock, D. Bartlett Jr., and J. C. Leiter Unilateral microdialysis of gabazine in the dorsal medulla reverses thermal prolongation of the laryngeal chemoreflex in decerebrate piglets J Appl Physiol, November 1, 2007; 103(5): 1864 - 1872. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Xia, T. A. Damon, J. C. Leiter, and D. Bartlett Jr. Focal warming in the nucleus of the solitary tract prolongs the laryngeal chemoreflex in decerebrate piglets J Appl Physiol, January 1, 2007; 102(1): 54 - 62. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Ambalavanar, L. Purcell, M. Miranda, F. Evans, and C. L. Ludlow Selective Suppression of Late Laryngeal Adductor Responses by N-Methyl-D-Aspartate Receptor Blockade in the Cat J Neurophysiol, March 1, 2002; 87(3): 1252 - 1262. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Abu-Shaweesh, I. A. Dreshaj, M. A. Haxhiu, and R. J. Martin Central GABAergic mechanisms are involved in apnea induced by SLN stimulation in piglets J Appl Physiol, April 1, 2001; 90(4): 1570 - 1576. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Bongianni, D. Mutolo, M. Carfi, G. A. Fontana, and T. Pantaleo Respiratory neuronal activity during apnea and poststimulatory effects of laryngeal origin in the cat J Appl Physiol, September 1, 2000; 89(3): 917 - 925. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
