Back to Search
Start Over
Activation of spinal d1/d5 receptors induces late-phase LTP of C-fiber-evoked field potentials in rat spinal dorsal horn.
- Source :
-
Journal of neurophysiology [J Neurophysiol] 2005 Aug; Vol. 94 (2), pp. 961-7. Date of Electronic Publication: 2005 Apr 13. - Publication Year :
- 2005
-
Abstract
- Long-term potentiation (LTP) of C-fiber-evoked field potentials in spinal dorsal horn may be relevant to pathological pain. Our previous work has shown that the late phase of the spinal LTP is protein synthesis-dependent. Considerable evidence has accumulated that dopamine D1/D5 receptors are important for late-phase LTP in hippocampus. In this study, the role of D1/D5 receptors in LTP of C-fiber-evoked field potentials in spinal dorsal horn was evaluated in urethan-anesthetized Sprague-Dawley rats. We found the following. 1) Spinal application of SKF 38393, a D1/D5 receptor agonist, induced a slowly developed LTP of C-fiber-evoked field potentials, lasting for >10 h, and the effect was blocked by the D1/D5 antagonist SCH 23390, whereas a D2 receptor agonist (quinpirole) induced depression of C-fiber responses, lasting for 2 h. 2) The potentiation produced by D1/D5 receptor agonist occluded the late phase but not the early phase of the spinal LTP produced by tetanic stimulation. 3) SCH 23390 selectively depressed the late-phase LTP, when applied 40 min before tetanic stimulation. 4) The D1/D5 agonist-induced potentiation is blocked by the protein synthesis inhibitor anisomycin. 5) Activation of protein kinase A by spinal application of 8-Br-cAMP also induced spinal LTP, and the action occluded the potentiation induced by the D1/D5 receptor agonist. These results suggest that the spinal D1/D5 receptors participate in the protein synthesis-dependent late-phase LTP of C-fiber-evoked field potentials in spinal dorsal horn through the cAMP signaling pathway.
- Subjects :
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine pharmacology
8-Bromo Cyclic Adenosine Monophosphate pharmacology
Animals
Anisomycin pharmacology
Benzazepines pharmacology
Denervation methods
Dopamine Agonists pharmacology
Dopamine Antagonists pharmacology
Electric Stimulation methods
Evoked Potentials drug effects
Evoked Potentials radiation effects
Male
Posterior Horn Cells radiation effects
Protein Synthesis Inhibitors pharmacology
Rats
Rats, Sprague-Dawley
Reaction Time drug effects
Reaction Time physiology
Reaction Time radiation effects
Receptors, Dopamine D5
Spinal Cord cytology
Time Factors
Evoked Potentials physiology
Long-Term Potentiation physiology
Nerve Fibers, Unmyelinated physiology
Posterior Horn Cells physiology
Receptors, Dopamine D1 physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3077
- Volume :
- 94
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Journal of neurophysiology
- Publication Type :
- Academic Journal
- Accession number :
- 15829590
- Full Text :
- https://doi.org/10.1152/jn.01324.2004