| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
NEUROSCIENCE |
1 Neurological Sciences Institute, Oregon Health & Science University, Beaverton, OR 97006, USA
In urethane–chloralose anaesthetized, neuromuscularly blocked, ventilated rats, we examined the effects on sympathetic outflow to brown adipose tissue (BAT) of separate and simultaneous spinal microinjections of NMDA and serotonin. Microinjection of NMDA (12 pmol) into the right T4 spinal intermediolateral nucleus (IML) immediately increased ipsilateral brown adipose tissue (BAT) sympathetic nerve activity (SNA; peak: +546% of control), BAT thermogenesis (+0.8°C) and heart rate (+53 beats min–1), whereas microinjection of a lower dose of NMDA (1.2 pmol) did not change any of the recorded variables. Microinjection of 5-hydroxytryptamine (5-HT, 2 nmol) into the T4 IML increased BAT SNA (peak: +342% of control) at a long latency (mean onset: 23min). The long latency 5-HT-evoked increase in BAT SNA was prevented by microinjection of methysergide (600 pmol) into the T4 IML. The increases in BAT SNA evoked by T4 IML microinjections of NMDA (12 pmol) were significantly potentiated (two to three times larger than the response to NMDA alone) following T4 IML microinjections of 5-HT (100 pmol to 2 nmol, but not 20 pmol). Also, microinjection of 5-HT (200 pmol) converted the subthreshold dose of NMDA (1.2 pmol) into an effective dose for increasing BAT SNA and heart rate. The 5-HT-mediated potentiation of the increase in BAT SNA evoked by microinjection of NMDA into the T4 IML was reversed by microinjection of methysergide (600 pmol) into the T4 IML. These results demonstrate that BAT SNA and thermogenesis can be driven by activation of spinal excitatory amino acid or 5-HT receptors and that concomitant activation of spinal NMDA and 5-HT receptors can act synergistically to markedly increase BAT SNA and thermogenesis.
(Received 5 July 2006;
accepted after revision 13 September 2006;
first published online 14 September 2006)
Corresponding author C. J. Madden: Neurological Sciences Institute/OHSU, 505 NW 185th Avenue, Beaverton, OR 97006, USA. Email: maddench{at}ohsu.edu
This article has been cited by other articles:
|
|
 |
|
  J. A. Rathner, C. J. Madden, and S. F. Morrison Central pathway for spontaneous and prostaglandin E2-evoked cutaneous vasoconstriction Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2008; 295(1): R343 - R354. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. F. Morrison, K. Nakamura, and C. J. Madden Central control of thermogenesis in mammals Exp Physiol, July 1, 2008; 93(7): 773 - 797. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. R. Hodges, G. J. Tattersall, M. B. Harris, S. D. McEvoy, D. N. Richerson, E. S. Deneris, R. L. Johnson, Z.-F. Chen, and G. B. Richerson Defects in Breathing and Thermoregulation in Mice with Near-Complete Absence of Central Serotonin Neurons J. Neurosci., March 5, 2008; 28(10): 2495 - 2505. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. W. Brown, E. A. Sirlin, A. M. Benoit, J. M. Hoffman, and R. A. Darnall Activation of 5-HT1A receptors in medullary raphe disrupts sleep and decreases shivering during cooling in the conscious piglet Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2008; 294(3): R884 - R894. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. E. Rusyniak, M. V. Zaretskaia, D. V. Zaretsky, and J. A. DiMicco 3,4-Methylenedioxymethamphetamine- and 8-Hydroxy-2-di-n-propylamino-tetralin-Induced Hypothermia: Role and Location of 5-Hydroxytryptamine 1A Receptors J. Pharmacol. Exp. Ther., November 1, 2007; 323(2): 477 - 487. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. R. Brumley, I. D. Hentall, A. Pinzon, B. H. Kadam, A. Blythe, F. J. Sanchez, A. M. Taberner, and B. R. Noga Serotonin Concentrations in the Lumbosacral Spinal Cord of the Adult Rat Following Microinjection or Dorsal Surface Application J Neurophysiol, September 1, 2007; 98(3): 1440 - 1450. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Hoffman, J. W. Brown, E. A. Sirlin, A. M. Benoit, W. H. Gill, M. B. Harris, and R. A. Darnall Activation of 5-HT1A receptors in the paragigantocellularis lateralis decreases shivering during cooling in the conscious piglet Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R518 - R527. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. Deuchars Multi-tasking in the spinal cord - do 'sympathetic' interneurones work harder than we give them credit for? J. Physiol., May 1, 2007; 580(3): 723 - 729. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
