| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Canadian Journal of Anesthesia, Vol 45, 907-912, Copyright © 1998 by Canadian Anesthesiologists' Society
ARTICLES |
T Nishiyama
Department of Anesthesiology, University of Tokyo, Faculty of Medicine, Japan.
PURPOSE: There are no rodent models of chronic epidural catheterisation which can induce clinically relevant analgesic effects of morphine (potency ratio of intrathecal:epidural = 10 to 30:1). The purpose of this study was to investigate a new rat model of chronic epidural catheterisation by comparing the analgesic effect of epidural and intrathecal morphine. METHODS: In Sprague-Dawley rats, for epidural catheterisation, a skin incision and muscle dissection were made at T13 level in the midline. The intervertebral ligament was cut to insert an epidural catheter (polyethylene tube; outer diameter 0.14 mm) 2 cm caudally. The distal end of the catheter (0.61 mm) was passed s.c. to exit in the dorsal neck area. For intrathecal catheterisation, the atlanto-occipital membrane was incised to insert a catheter (0.61 mm) 8.5 cm caudally. The effects of morphine (1, 3, 10, 30, or 100 micrograms.10 microliters-1 intrathecally, and 30, 100, or 300 micrograms.5, 10, or 20 microliters-1 epidurally) on thermal escape latency were investigated by a hot box test. Behaviour and motor function were also tested. RESULTS: A volume of 20 microliters induced greater analgesic effect than 5 and 10 microliters epidural administration. The ED50 of epidural morphine (94.1 micrograms) was 30 times more than that of intrathecal morphine (3.1 micrograms). CONCLUSION: A new rat model of chronic epidural catheterisation is described, which provides a similar analgesic epidural: intrathecal potency ratio for morphine to that in humans when morphine is administered in a volume of 20 microliters.
This article has been cited by other articles:
![]() |
H. C. Jin, A. J. Keller, J. K. Jung, A. Subieta, and T. J. Brennan Epidural Tezampanel, an AMPA/Kainate Receptor Antagonist, Produces Postoperative Analgesia in Rats Anesth. Analg., October 1, 2007; 105(4): 1152 - 1159. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Nishiyama and K. Hanaoka The Effects of Epidural Bupivacaine, Morphine, and Their Combination on Thermal Nociception with Different Stimulus Intensity in Rats Anesth. Analg., September 1, 2000; 91(3): 652 - 656. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Nishiyama and K. Hanaoka Reproducibility of the Drug Effects over Time on Chronic Lumbar Epidural Catheterization in Rats Anesth. Analg., December 1, 1999; 89(6): 1492 - 1492. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |