This research program will continue to investigate the mediators and modulation of pain. In the past, we focused on inhibitory modulation. During the current funding period, however, we also characterized a facilitatory component to the modulation of nociception. Experiments proposed for the next project period will continue to quantitatively study the facilitatory component of nociceptive modulation and, in addition, will examine the release and role(s) of local, spinal mediators in nociception.
The Specific Aims are to: 1. quantitatively characterize the facilitatory modulation of (1) spinal nociceptive withdrawal reflexes evoked by noxious cutaneous thermal and mechanical stimuli and (2) spinal projection and spinothalamic lumbar dorsal horn neuron responses to both noxious and non-noxious cutaneous thermal and mechanical stimuli. These studies will include examination of the supraspinal circuitry/relays, spinal pathways and spinal neurotransmitters that mediate descending facilitation. 2. to examine the role(s) of excitatory amino acids, prostanoids and nitric oxide (NO) in local, spinal mediation of noxious thermal and mechanical transmission. 3. to examine the role(s) of prostanoids and NO as mediators of nociception in sensory neurons by studying their release from dorsal root ganglion cells maintained in culture.
These Specific Aims are a logical extension of the current project and will continue a focused, systematic investigation into the mechanisms and modulation of nociception. Previous work on this project provides the necessary converging background information against which to meaningfully compare and interpret the results expected in the proposed studies. The proposed experiments will quantitatively examine (1) the facilitatory component of descending modulation and (2) local mediation and modulation of nociception.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37DA002879-25
Application #
6342243
Study Section
Special Emphasis Panel (NSS)
Program Officer
Thomas, David D
Project Start
1981-09-30
Project End
2002-12-31
Budget Start
2001-02-01
Budget End
2001-12-31
Support Year
25
Fiscal Year
2001
Total Cost
$334,181
Indirect Cost
Name
University of Iowa
Department
Pharmacology
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Buhler, A V; Proudfit, H K; Gebhart, G F (2008) Neurotensin-produced antinociception in the rostral ventromedial medulla is partially mediated by spinal cord norepinephrine. Pain 135:280-90
Gebhart, G F (2004) Descending modulation of pain. Neurosci Biobehav Rev 27:729-37
Buhler, A V; Proudfit, H K; Gebhart, G F (2004) Separate populations of neurons in the rostral ventromedial medulla project to the spinal cord and to the dorsolateral pons in the rat. Brain Res 1016:12-9
Friedrich, Ann E; Gebhart, G F (2003) Modulation of visceral hyperalgesia by morphine and cholecystokinin from the rat rostroventral medial medulla. Pain 104:93-101
Hartwig, Andrew C; Mathias, Sarah I; Law, Alan S et al. (2003) Characterization and opioid modulation of inflammatory temporomandibular joint pain in the rat. J Oral Maxillofac Surg 61:1302-9
Zhuo, Min; Gebhart, G F (2002) Facilitation and attenuation of a visceral nociceptive reflex from the rostroventral medulla in the rat. Gastroenterology 122:1007-19
Pogatzki, Esther M; Gebhart, G F; Brennan, Timothy J (2002) Characterization of Adelta- and C-fibers innervating the plantar rat hindpaw one day after an incision. J Neurophysiol 87:721-31
Pogatzki, Esther M; Urban, Mark O; Brennan, Timothy J et al. (2002) Role of the rostral medial medulla in the development of primary and secondary hyperalgesia after incision in the rat. Anesthesiology 96:1153-60
Hamalainen, Minna M; Gebhart, G F; Brennan, Timothy J (2002) Acute effect of an incision on mechanosensitive afferents in the plantar rat hindpaw. J Neurophysiol 87:712-20
Zhuo, M; Gebhart, G F (2002) Modulation of noxious and non-noxious spinal mechanical transmission from the rostral medial medulla in the rat. J Neurophysiol 88:2928-41

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