Open AccessEffects of intrathecal 6‐hydroxydopamine, α 1 and α 2 adrenergic receptor antagonists on antinociception of propofol in mice
Author(s) -
GE Zhijun,
ZENG Yinming,
TAN Yongfei
Publication year - 2005
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2005.00033.x
Subject(s) - propofol , yohimbine , prazosin , tail flick test , antagonist , pharmacology , hydroxydopamine , nociception , medicine , chemistry , endocrinology , anesthesia , receptor , dopamine , dopaminergic
Aim: To investigate the relationship between spinal cord norepinephrine, α 1 and α 2 adrenergic receptors and antinociception of propofol in mice. Methods: Kunming mice were used. Antinociceptive tests were investigated with the tail‐immersion test and the acetic acid‐induced writhing test. The effects of subcutaneous (sc), intrathecal (ith) and intracerebroventricular (icv) injection propofol on pain threshold were observed. The influences of pretreatment with ith 6‐hydroxydopamine, α 1 R antagonist prazosin, or α 2 R antagonist yohimbine on the antinociception of propofol were studied. Results: Significant antinociception was produced by propofol (25, 50 mg/kg, sc) and propofol (20, 40 μg, ith) in tail‐immersion test and acetic the acid‐induced writhing test ( P <0.05 or P < 0.01). Icv propofol (10, 20, and 40 μg) did not produce any effect on pain threshold in mice ( P > 0.05). The 6‐hydroxydopamine (5 and 10 μg), prazosin (5 and 10 μg), or yohimbine (5 and 10 μg) ith alone did not affect basal tai‐flick latency (TFL) in conscious mice, but significantly reduced the TFL as measured by tail‐immersion test in propofol (50 mg/kg, sc)‐treated mice, compared with basal TFL and vehicle groups ( P < 0.05 or P < 0.01). Conclusion: The spinal cord is a target of propofol antinociception. In mice propofol antinociception is partly mediated by spinal norepinephrine, α 1 R and α 2 R.