QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, October 27, 2004, 24(43):9561-9571; doi:10.1523/JNEUROSCI.1817-04.2004

This Article Full Text Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (14) Citing Articles via Google Scholar Google Scholar Articles by McLean, D. L. Articles by Sillar, K. T. Search for Related Content PubMed PubMed Citation Articles by McLean, D. L. Articles by Sillar, K. T. Pubmed/NCBI databases Compound via MeSH Substance via MeSH Hazardous Substances DB (D)-PENICILLAMINE GLYCINE NITRIC OXIDE PHENTOLAMINE

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Metamodulation of a Spinal Locomotor Network by Nitric Oxide

David L. McLean and Keith T. Sillar

Division of Biomedical Sciences, School of Biology, University of St Andrews, St Andrews, Fife KY16 9TS, United Kingdom

Flexibility in the output of spinal networks can be accomplished by the actions of neuromodulators; however, little is known about how the process of neuromodulation itself may be modulated. Here we investigate the potential "meta"-modulatory hierarchy between nitric oxide (NO) and noradrenaline (NA) in Xenopus laevis tadpoles. NO and NA have similar effects on fictive swimming; both potentiate glycinergic inhibition to slow swimming frequency and GABAergic inhibition to reduce episode durations. In addition, both modulators have direct effects on the membrane properties of motor neurons. Here we report that antagonism of noradrenergic pathways with phentolamine dramatically influences the effect of the NO donor S-nitroso-N-acetylpenicillamine (SNAP) on swimming frequency, but not its effect on episode durations. In contrast, scavenging extracellular NO with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) does not influence any of the effects of NA on fictive swimming. These data place NO above NA in the metamodulatory hierarchy, strongly suggesting that NO works via a noradrenergic pathway to control glycine release but directly promotes GABA release. We confirmed this possibility using intracellular recordings from motor neurons. In support of a natural role for NO in the Xenopus locomotor network, PTIO not only antagonized all of the effects of SNAP on swimming but also, when applied on its own, modulated both swimming frequency and episode durations in addition to the underlying glycinergic and GABAergic pathways. Collectively, our results illustrate that NO and NA have parallel effects on motor neuron membrane properties and GABAergic inhibition, but that NO serially metamodulates glycinergic inhibition via NA.

Key words: nitric oxide; noradrenaline; inhibition; brainstem; spinal cord; locomotion; Xenopus laevis

---

Received Oct 28, 2003; revised September 9, 2004; accepted September 10, 2004.

This article has been cited by other articles:

				D. M. Blitz, R. S. White, S. R. Saideman, A. Cook, A. E. Christie, F. Nadim, and M. P. Nusbaum A newly identified extrinsic input triggers a distinct gastric mill rhythm via activation of modulatory projection neurons J. Exp. Biol., March 15, 2008; 211(6): 1000 - 1011. [Abstract] [Full Text] [PDF]

				P. L. Newland and P. Yates Nitrergic modulation of an oviposition digging rhythm in locusts J. Exp. Biol., December 15, 2007; 210(24): 4448 - 4456. [Abstract] [Full Text] [PDF]

				M. S. Kirby and M. P. Nusbaum Peptide Hormone Modulation of a Neuronally Modulated Motor Circuit J Neurophysiol, December 1, 2007; 98(6): 3206 - 3220. [Abstract] [Full Text] [PDF]

				A. Kyriakatos and A. El Manira Long-Term Plasticity of the Spinal Locomotor Circuitry Mediated by Endocannabinoid and Nitric Oxide Signaling J. Neurosci., November 14, 2007; 27(46): 12664 - 12674. [Abstract] [Full Text] [PDF]

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help