HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited 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 (18) Citing Articles via Google Scholar Google Scholar Articles by Mason, P. Search for Related Content PubMed PubMed Citation Articles by Mason, P.

INVITED REVIEW

DECONSTRUCTING ENDOGENOUS PAIN MODULATIONS

Department of Neurobiology, Pharmacology and Physiology and Committee on Neurobiology, University of Chicago, Chicago, Illinois

Submitted 9 March 2005; accepted in final form 7 April 2005

ABSTRACT

A pathway from the midbrain periaqueductal gray (PAG) through the ventromedial medulla (VMM) to the dorsal horn constitutes a putative endogenous nociceptive modulatory system. Yet activation of neurons in both PAG and VMM changes the responses of dorsal horn cells to nonnoxious stimuli and elicits motor and autonomic reactions that are not directly related to nociception. Activation of mu-opioid receptors in VMM and PAG also modifies processes in addition to nociceptive transmission. The descending projections of VMM neurons are not specific to nociception as VMM projects to the spinal superficial dorsal horn where thermoreceptors as well as nociceptors terminate. In addition, experiments with pseudorabies virus demonstrate multisynaptic pathways from VMM to sympathetic and parasympathetic target organs. VMM neurons respond to both noxious and unexpected innocuous stimuli of multiple modalities, and change their discharge during behaviors unrelated to pain such as micturition/continence and sleep/wake. In conclusion, all available evidence argues against the idea that PAG and VMM target nociception alone. Instead these brain stem sites may effect homeostatic adjustments made necessary by salient situations including but not limited to injury.

This article has been cited by other articles:

				E. E. Benarroch Descending monoaminergic pain modulation: Bidirectional control and clinical relevance Neurology, July 15, 2008; 71(3): 217 - 221. [Abstract] [Full Text] [PDF]

				B. A. Graham, A. M. Brichta, and R. J. Callister Recording Temperature Affects the Excitability of Mouse Superficial Dorsal Horn Neurons, In Vitro J Neurophysiol, May 1, 2008; 99(5): 2048 - 2059. [Abstract] [Full Text] [PDF]

				C. J. Heckman, A. S. Hyngstrom, and M. D. Johnson Active properties of motoneurone dendrites: diffuse descending neuromodulation, focused local inhibition J. Physiol., March 1, 2008; 586(5): 1225 - 1231. [Abstract] [Full Text] [PDF]

				J. D. Carlson, J. J. Maire, M. E. Martenson, and M. M. Heinricher Sensitization of Pain-Modulating Neurons in the Rostral Ventromedial Medulla after Peripheral Nerve Injury J. Neurosci., November 28, 2007; 27(48): 13222 - 13231. [Abstract] [Full Text] [PDF]

				B. A. Graham, A. M. Brichta, and R. J. Callister Moving From an Averaged to Specific View of Spinal Cord Pain Processing Circuits J Neurophysiol, September 1, 2007; 98(3): 1057 - 1063. [Abstract] [Full Text] [PDF]

				Y. Lu and E. R. Perl Selective action of noradrenaline and serotonin on neurones of the spinal superficial dorsal horn in the rat J. Physiol., July 1, 2007; 582(1): 127 - 136. [Abstract] [Full Text] [PDF]

				D. Blivis, G. Z. Mentis, M. J. O'Donovan, and A. Lev-Tov Differential Effects of Opioids on Sacrocaudal Afferent Pathways and Central Pattern Generators in the Neonatal Rat Spinal Cord J Neurophysiol, April 1, 2007; 97(4): 2875 - 2886. [Abstract] [Full Text] [PDF]

				M. W. Nason Jr and P. Mason Medullary Raphe Neurons Facilitate Brown Adipose Tissue Activation J. Neurosci., January 25, 2006; 26(4): 1190 - 1198. [Abstract] [Full Text] [PDF]