Antinociceptive Effect of the S(+)-Enantiomer of Ketamine on Carrageenan Hyperalgesia after Intrathecal Administration in Rats (original) (raw)
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TURKISH JOURNAL OF MEDICAL SCIENCES, 2019
2.1. Preparation of liposome formulations Structurally multilamellar liposomes were prepared from dipalmitoyl phosphatidyl choline (DPPC)-cholesterol in 50% ratio using the dry-film hydration by vortex mixer Background/aim: Based on our previous in vitro study with multilamellar liposomal bupivacaine (MLB) versus bupivacaine alone in artificial cerebrospinal fluid, we aimed to investigate in vivo antinociceptive effect of intrathecal MLB by determining tail flick latency (TFL) time after thermal stimulation in rats. Materials and methods: After preparing MLB and high-yield drug entrapment in liposome (HYDEL) bupivacaine, 18 female Wistar rats were assigned to 3 groups as control (bupivacaine) and study groups (MLB and HYDEL bupivacaine) including 6 rats in each group to administer these drugs intrathecally. Antinociceptive activity was determined in terms of TFL time after thermal stimulation. Maximum possible effect (MPE) calculated from TFL times and rats with motor block were documented. Results: TFL times after intrathecal injection of HYDEL bupivacaine were significantly longer than that of the control and MLB groups (P < 0.05) and returned to baseline 180 min after intrathecal injection. MPE (100%) with intrathecal HYDEL bupivacaine occurred between 10 to 45 min. Afterwards, MPEs were 70% and 50% for the control and MLB groups, respectively. Motor block disappeared after 20 min in the study groups while it lasted 75 min in the control. Conclusion: Intrathecal administration of MLB and HYDEL bupivacaine in rats resulted in longer duration of antinociceptive activity with shorter motor block duration.
A dose–response study of epidural liposomal bupivacaine in rabbits
Journal of Controlled Release, 1999
Liposomes are drug delivery systems used to prolong local effects of bupivacaine. We studied the relationships between motor and hemodynamic changes and epidural doses of plain bupivacaine (P) and liposomal bupivacaine (L) in rabbits equipped with chronical lumbar epidural and femoral arterial catheters. Liposomal (phosphatidylcholine-cholesterol) 21 suspensions contained 20 mg ml of lipid, and different doses of bupivacaine (Lipo 7.557.5-; Lipo 3.753.75-; Lipo 2.552.5-; Lipo 1.251.25-; and Lipo 0.750.65-mg of bupivacaine per ml). Forty rabbits were randomly assigned to five groups to receive epidural anesthesia (1 ml) as follows: Groups I to V received 0.65 to 7.5 mg of bupivacaine as P then as L. Release rate of bupivacaine from liposome was significantly slower using Lipo 3.7 than after Lipo 2.5 (T was 3.9 h and 1.7 d h respectively). Increasing the doses of L and P resulted in faster onset time for complete motor blockade and in a prolonged duration of motor effects. Liposomal formulation appears to be a powerful delivery system to prolong the motor effects of bupivacaine since E was lower and E higher than after the use of plain solution (E 4.4961.81 mg and E 152640 50 max 50 max min for P; and E 2.6160.23 mg and E 20269 min for L). Hemodynamic changes were linearly related to doses of 50 max bupivacaine injected. The best bupivacaine-to-lipid ratio to prolong motor effects using our model was 3.75 mg and 20.0 mg respectively (Lipo 3.7).
Anesthesia & Analgesia, 2001
To investigate the neurologic mechanisms of acidic local anesthetic-induced low back pain in humans, we administered bupivacaine and buffered saline at acidic or alkalinized pH at the L5 dorsal root ganglion (DRG) of rats via a hole drilled through the transverse process covering the DRG. Behavioral changes were tested before and after bupivacaine or saline administration. Results indicate that acute single-dose infusion of the DRG with bupivacaine (0.5%) at acidic pH (5.5) induced ipsilateral mechanical hyperalgesia that lasted for 7 days. Acute infusion of alkalinized bupivacaine (pH 7.2), however, caused only minor hyperalgesia that lasted Ͻ3 days. Similar results were obtained when bupivacaine was replaced with saline. Alternatively, chronic delivery of acidic saline to the DRG via a subcutaneously implanted osmotic pump resulted in a significant decrease in the withdrawal threshold on the ipsilateral hind paw that lasted for 10 days. In rats receiving chronic treatment of the DRG with alkalinized saline, mechanical hyperalgesia lasted for only 3 days. The results demonstrated that acidic bupivacaine deposited at the DRG causes pain and hyperalgesia when the effects of the local anesthetic have dissipated. These findings may explain the limited therapeutic effects of some acidic local anesthetics used for management of cancerrelated and chronic back pain. (Anesth Analg 2001;93:466 -71)
Korean Journal of Anesthesiology, 2022
Background: Animal and other experimental studies have demonstrated increased block time and quality when alpha and beta cyclodextrin drugs are combined with the local anesthetic. However, to our knowledge there exists no study that has utilized gamma cyclodextrins in such a combination. In this present study we used an animal model to evaluate the effect of different doses of combined administration of gamma cyclodextrin (sugammadex) and bupivacaine on sciatic nerve blockage times in rats. Methods: Sciatic block was performed with 0.20 mL mixture in all groups. This mixture consisted of 0.2ml saline in the Sham group, 0.2ml sugammadex in Group S and 0.16ml bupivacaine 0.5% and 0.04ml saline in Group B. In the experimental groups, in addition to 0.16ml bupivacaine 0.5%, 0.01 ml sugammadex and 0.03ml saline was added in Group BS1 0.02ml sugammadex and 0.02ml saline was added in Group BS2 and 0.04ml sugammadex was added in Group BS4. Proprioception, nociception and motor function was evaluated until sciatic block was completely reversed. Results: Motor, proprioceptive and nociceptive block occurred in all experimental groups within 5 minutes. In Group BS4 the duration of motor, proprioceptive and nociceptive blocks significantly increased compared with other experimental groups. However in Group BS1 and Group BS2, only the duration of nociceptive block significantly increased. Conclusion: Combined administration of sugammadex and bupivacaine when performing sciatic nerve block in rats leads to a significant prolongation of motor, proprioceptive and nociceptive block times.
Brazilian journal of anesthesiology (Elsevier)
This study investigates analgesic and nociceptive effects of adding dexmedetomidine to bupivacaine neuraxial anesthesia through Tail-flick (TF) and Hot-plate (HP) tests and the pathohistological changes on spinal nerves and nerve roots through light microscopy. Forty anesthetized, male Sprague-Dawley rats were intrathecally catheterized. Basal values of TF and HP tests were measured before and after catheterization. Thirty-six successfully catheterized rats were assigned to four groups. Group B received 10 μg bupivacaine, Group BD3 received 10 μg bupivacaine + 3 μg dexmedetomidine, Group BD10 received 10 μg bupivacaine + 10 μg dexmedetomidine and Control group received 10 μL volume of artificial cerebrospinal fluid. TF and HP tests were performed between the 5(th) and 300(th) minutes of drug administration. Twenty-four hours after administration of drugs, rats were sacrificed and spinal cord and nerve roots were removed for pathological investigation. Baseline values of the TF and H...
Prolongation of Nerve and Epidural Anesthetic Blockade by Bupivacaine in a Lipid Emulsion
Anesthesia & Analgesia, 1999
We assessed the effect of a lipid emulsion of bupivacaine on prolonging peripheral nerve and epidural anesthetic blockade in the rat. The intensity and duration of motor and sensory blockade produced by a single injection of aqueous solution (BPV-as) and lipid emulsion (BPV-em) preparations of 0.5% bupivacaine were evaluated by electrophysiological methods. Both preparations induced complete, reversible motor and sensory blockade after injection. The latency time to the maximal blockade and the duration of anesthetic blockade were more prolonged for BPV-em than for BPV-as. The increase in duration of maximal blockade was 1.4 times for nerve and 1.3 times for epidural anesthesia. Histological evaluation of spinal roots and spinal cord sections did not show any abnormalities or differences between animals injected with BPV-as and those injected with BPV-em. Pharmacokinetic studies showed lower plasma peak concentration and a longer elimination half-life for BPV-em than for BPV-as. Thus, BPV-em prolongs the effects of local anesthetics, allows a similar degree of blockade, and reduces the systems toxic effects of anesthetics compared with BPV-as. Implications: We assessed a lipid emulsion containing bupivacaine for peripheral nerve and epidural anesthetic blockade in the rat. The emulsion allowed a complete blockade, while increasing the duration of the anesthetic effect (by 30%-40%), compared with the standard bupivacaine aqueous solution.
Encapsulation of mepivacaine prolongs the analgesia provided by sciatic nerve blockade in mice
Canadian Journal of Anesthesia/Journal canadien d'anesthésie, 2004
P Pu ur rp po os se e: : Liposomal formulations of local anesthetics (LA) are able to control drug-delivery in biological systems, prolonging their anesthetic effect. This study aimed to prepare, characterize and evaluate in vivo drug-delivery systems, composed of large unilamellar liposomes (LUV), for bupivacaine (BVC) and mepivacaine (MVC).
Annals of Medical Research, 2020
The aim of this study was to investigate the effect of combining sodium bicarbonate with bupivacaine on prolonging peripheral nerve block time. Material and Method: Following the approval of the required Ethics Committee, 24 male New Zealand rabbit (4250-5350 g) were randomized and divided into three groups. Group 1 sham n:8; Group 2 (bupivacaine): 0.5 mL of 0.5% bupivacaine (0.5 mg / kg) injected into the perineural area. n:8; and Group 3 (bupivacaine + sodium bicarbonate): 0.5 ml of 0.5% bupivacaine + sodium bicarbonate (125 ml of 8.4% injected into the perineural area. n: 8. After the skin was closed in all groups, the paw pull response was monitored and recorded every 30 minutes until the sensory block of the experimental animal returned back. Hot-plate test was used for analgesia evaluation. In addition, tissue histopathology was examined for histopathological evaluation of the injection site. Sensory block was evaluated with claw tightening test and claw pull test (hot-plate) response. The measurements were carried out every 30 minutes for 120 minutes or until the block was completely resolved. Results: 30., 60. and 90.min paw pull response in Group 2 and Group 3 showed statistically significant elongation when compared to Group 1, this difference disappeared in 120 minutes. Compared to the sham group, the 30 min hot plate and claw pull response was significantly longer in group 3 (sodium bicarbonate and bupivacaine), this difference disappeared in 60 minutes (p = 0.018). Conclusion: When sodium bicarbonate and bupivacaine are combined, it was seen in this study that the sensory block was prolonged. We believe that the current results can be used as a guide for future studies
Anesthetic activity of the lipospheres bupivacaine delivery system in the rat
Anesthesia progress, 1992
The Lipospheres Bupivacaine Delivery System (bupivacaine-lipospheres) is a novel sustained-release local anesthetic preparation that has recently been made available for research purposes. This investigation compared the local anesthetic efficacy and safety of 2% bupivacaine-lipospheres, 0.5% bupivacaine plus 1:200,000 epinephrine, lipospheres plain, and physiologic saline following subcutaneous tail injection in the rat. A modified tail-flick paradigm was used to assess local anesthetic efficacy. Animals treated with 2% bupivacaine-lipospheres or 0.5% bupivacaine with epinephrine displayed significant antinociception (P < 0.05) compared to saline or lipospheres plain with 5 min of injection. Bupivacaine with epinephrine had an anesthetic duration of 30 min, whereas 2% bupivacaine-lipospheres had a duration of 3 hr. The local anesthetic blockade produced by both active solutions was completely reversible. All animals gained weight normally during the 1-wk course of the study, and...