Loading...
Please wait, while we are loading the content...
Similar Documents
Differential presynaptic effects of opioid agonists on Adelta- and C-afferent glutamatergic transmission to the spinal dorsal horn.
| Content Provider | Semantic Scholar |
|---|---|
| Author | Ikoma, Miho Kohno, Tatsuro Baba, Hiroshi |
| Copyright Year | 2007 |
| Abstract | BACKGROUND Although intrathecal administration of opioids produces antinociceptive effects in the spinal cord, it has not been established whether intrathecal opioid application more effectively terminates C fiber-mediated pain than A fiber-mediated pain. Here, the authors focus on the differences in opioid actions on Adelta- and C-afferent responses. METHODS Using the whole cell patch clamp technique, the authors investigated the presynaptic inhibitory actions of micro-, delta-, and kappa-opioid receptor agonists on primary afferent-evoked excitatory postsynaptic currents (EPSCs) in substantia gelatinosa neurons of adult rat spinal cord slices. RESULTS The micro agonist DAMGO (0.1, 1 microM) reduced the amplitude of glutamatergic monosynaptic Adelta- or C fiber-evoked EPSCs. C fiber-evoked EPSCs were inhibited to a greater extent than Adelta fiber-evoked EPSCs. The delta agonist DPDPE (1, 10 microM) produced modest inhibition of Adelta- or C fiber-evoked EPSCs. In contrast, the kappa agonist U69593 (1 microM) did not affect the amplitude of either Adelta or C fiber-evoked EPSCs. CONCLUSIONS These results indicate that opioids suppress excitatory synaptic transmission mainly through activation of micro receptors on primary afferent C fibers. Given that the substantia gelatinosa is the main termination of Adelta and C fibers transmitting nociceptive information, the current findings may partially explain the different potency of opioid agonists. |
| Starting Page | 1447 |
| Ending Page | 1457 |
| Page Count | 11 |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://anesthesiology.pubs.asahq.org/pdfaccess.ashx?url=/data/journals/jasa/931058/0000542-200711000-00018.pdf |
| PubMed reference number | 18073556v1 |
| Volume Number | 107 |
| Issue Number | 5 |
| Journal | Anesthesiology |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | C Fibers Excitatory Postsynaptic Currents MERRF Syndrome OPIOID ANALGESICS Opioid Receptor Opioids Pain Postsynaptic Current Structure of posterior gray horn of spinal cord Substantia Gelatinosa Synaptic Transmission Tissue fiber |
| Content Type | Text |
| Resource Type | Article |
