ISSN:
1432-1912
Keywords:
Key words Clonidine
;
Morphine
;
Intrathecal
;
Spinal cord
;
Opioid tolerance
;
Alpha 2 adrenoceptor
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Previous animal studies have shown the antinociceptive effects of intrathecal clonidine and intrathecal morphine to be synergistic. This study investigated the intrathecal administration of multiple doses of this drug combination to examine the rate of development of tolerance and to determine whether there was any toxic effect on the spinal cord. Rats with indwelling intrathecal catheters were given saline, morphine (2.5–7.5 μg), clonidine (17.5 μg), or clonidine (17.5 μg) plus morphine (1 μg) intrathecally twice daily for 412 days (total of 9 doses). Hot plate and tail flick tests were conducted after the first, fifth and ninth doses. After the ninth dose animals were killed and their spinal cords were removed for histological examination. Tolerance developed to the antinociceptive effects of the drug combination, but at a slower rate than to morphine alone. No evidence of toxicity or injury to the spinal cord was observed other than changes which could be ascribed to the presence of the catheter.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00170161
