101. Synergistic Effects of Serotonin or Dopamine Combined With Lidocaine at Producing Nociceptive Block in Rats.
- Author
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Hung CH, Chiu CC, Liu KS, Chen YW, and Wang JJ
- Subjects
- Animals, Dose-Response Relationship, Drug, Drug Combinations, Drug Synergism, Injections, Subcutaneous, Male, Pain Measurement methods, Rats, Rats, Sprague-Dawley, Anesthetics, Local administration & dosage, Dopamine administration & dosage, Lidocaine administration & dosage, Pain Measurement drug effects, Serotonin administration & dosage
- Abstract
Background: The purpose of this experiment was to investigate the interactions of the local anesthetic lidocaine combined with an agent (serotonin or dopamine) as infiltrative anesthetics., Methods: Cutaneous analgesia was characterized by the blockade of the cutaneous trunci muscle reflex following 6 skin pinpricks on the rat back. Serotonin or dopamine at producing cutaneous analgesia in a dosage-dependent fashion was compared with lidocaine. Drug-drug interactions were calculated using the isobolographic analysis., Results: We revealed that serotonin, dopamine, and lidocaine provoked dose-related cutaneous analgesic effects. On the 50% effective dose basis, the rank of drugs' potency was found to be serotonin (1.70 [1.56-1.85] μmol) > lidocaine (5.18 [4.67-5.75] μmol) > dopamine (43.0 [40.9-45.2] μmol) (P < 0.01). At doses equivalent to their 25%, 50%, and 75% effective doses, serotonin or dopamine elicited a longer duration of action than lidocaine (P < 0.01) on producing cutaneous analgesia. Coadministration of serotonin or dopamine with lidocaine produced a synergistic effect., Conclusions: The preclinical data showed that serotonin and dopamine produce dose-related cutaneous analgesic effects as an infiltrative anesthetic. Serotonin has a better potency with a much longer duration of action compared with lidocaine at provoking cutaneous analgesia. Serotonin or dopamine as an adjuvant increases the quality of lidocaine in cutaneous analgesia.
- Published
- 2017
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