Ifenprodil for prolonged spinal blockades of motor function and nociception in rats

  • Pharmacol Rep. 2016 Apr;68(2):357-62. doi: 10.1016/j.pharep.2015.09.011.
Yu-Wen Chen  1 ,  Chong-Chi Chiu  2 ,  Jieh-Neng Wang  3 ,  Ching-Hsia Hung  4 ,  Jhi-Joung Wang  5
Affiliations
  • 1. Department of Physical Therapy, College of Health Care, China Medical University, Taichung, Taiwan; Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan.
  • 2. Department of General Surgery, Chi Mei Medical Center, Tainan and Liouying, Taiwan; Department of Electrical Engineering, Southern Taiwan University of Science and Technology, Tainan, Taiwan.
  • 3. Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
  • 4. Department of Physical Therapy, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Institute of Allied Health Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan. Electronic address: [email protected].
  • 5. Department of Medical Research, Chi Mei Medical Center, Tainan, Taiwan.
PMID: 26922539 DOI: 10.1016/j.pharep.2015.09.011
Abstract

Background: The aim of the study was to compare the proposed spinal anesthetic effect of ifenprodil, an a1 Adrenergic Receptor antagonist, with that of the long-acting local anesthetic bupivacaine.

Methods: After intrathecally injecting the rats with five different doses of each drug, the dose-response curves of ifenprodil and bupivacaine were constructed to obtain the 50% effective dose (ED50). The spinal blockades of motor function and nociception of ifenprodil were compared with that of bupivacaine.

Results: We showed that either ifenprodil or bupivacaine produced spinal blockades of motor function and nociception dose-dependently. On the ED50 basis, the potency of ifenprodil (0.42(0.38-0.46) μmol; 0.40(0.36-0.44) μmol) was equal (p>0.05) to that of bupivacaine (0.38(0.36-0.40) μmol; 0.35(0.32-0.38) μmol) in motor function and nociception, respectively. At the equianesthetic doses (ED25, ED50, and ED75), duration produced by ifenprodil was greater than that produced by bupivacaine in motor function and nociception (p<0.05 for the differences). Furthermore, both ifenprodil and bupivacaine showed longer duration of sensory blockade than that of motor blockade (p<0.05 for the differences).

Conclusions: The resulting data demonstrated that ifenprodil produces a dose-dependent local anesthetic effect in spinal anesthesia. Ifenprodil shows a more sensory-selective duration of action over motor block, whereas the duration of anesthesia is significantly longer with ifenprodil than with bupivacaine.

Keywords
Bupivacaine; Ifenprodil; Motor function; Nociception; Spinal block.
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