1998 Fiscal Year Final Research Report Summary
Antinociceptive interaction between epidurally administered opioids and local anesthetics
| Project/Area Number |
08671735
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Anesthesiology/Resuscitation studies
|
|---|
| Research Institution | Shimane Medical University |
|---|
Principal Investigator |
KOSAKA Yoshihiro Shimane Medical University, Anesthesiology, Professor, 医学部, 教授 (20045355)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
UCHIDA Hiroshi Shimane Medical University, Anesthesiology, Assistant Professor, 医学部, 講師 (70176692)
SAITO Yoji Shimane Medical University, Anesthesiology, Associate Professor, 医学部, 助教授 (50162243)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Keywords | opioid / local anesthetics / epidural / somatic pain / visceral pain |
|---|
| Research Abstract |
We evaluated the antinociceptive interaction between opioids and local anesthetics on both somatic and visceral stimuli in rats. Tail flick (TF) test and colorectal distention (CD) test were performed to estimate somatic and visceral antinociceptive effects, respectively. Rats were implanted epidural catheters and received an epidural injection of bupivacaine, fentanyl, or the combination of those. Epidurally administered bupivacaine and fentanyl increased TF latency and CD threshold in a dose-dependent fashion. The coadministration of low dose of bupivacaine and fentanyl, which had no antinociceptive effects alone, produced prolongation of TE latency and increased in CD threshold. The combination of bupivacaine and fentanyl did not potentiate motor paralysis.
Some rats were implanted intrathecal catheters. Morphine, lidocaine, or the combination of those was infused intrathecally at a constant rate of 1mu/h for 6 days. Intrathecally infused morphine and lidocaine produced dose-dependent antinociceptive effects in both TF and CD tests with peak effects on day 1, and the effects disappeared on day 4. Coinfusion of low dose of morphine and lidocaine, which had no effects by themselves, produced significant antinociception. Coinfused lidocaine potentiated the duration and the magnitude of morphine antinociception. Isobolographic analysis showed a synergistic interaction between morphine and lidocaine.
These results confirm that the combination of opioids and local anesthetics is clinically useful, potentiating the antinociceptive effects and reducing the incidence and severity of side effects.
|
