Effect of Zaprinast, a Phosphodiesterse Inhibitor, on Formalin-induced Nociception and Hemodynamics in the Rat Spinal Cord. |
Sung Keun Park, Chang Mo Kim, Sung Tae Jeong, Seok Jai Kim, Dong Jin Shin, Hong Beom Bae, Jeong Il Choi, Seong Wook Jeong, Sung Su Chung, Kyung Yeon Yoo, Chang Young Jeong, Myung Ha Yoon |
1Department of Anesthesiology and Pain Medicine, Medical School, Chonnam National University, Gwangju, Korea. mhyoon@chonnam.ac.kr 2Department of Anesthesiology School of Dentistry, Chonnam National University, Gwangju, Korea. |
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Abstract |
BACKGROUND Cyclic guanosine monophosphate (cGMP) is involved in antinociception and vascular relaxation. The effects of zaprinast, which increases the level of cGMP by inhibiting phosphodiesterase, in the spinal cord have not been reported. The aims of this study were to evaluate the effects of intrathecal zaprinast on stimulus evoked by formalin injection, and to observe hemodynamic change in the absence of formalin stimulation. METHODS Rats were implanted with lumbar intrathecal catheters. Intrathecal zaprinast was administered 10 min before formalin injection. After formalin injection, formalin-induced nociceptive behavior (flinching response) was observed for 60 min. Mean arterial pressure (MAP) and heart rate (HR) were measured after intrathecal delivery of zaprinast for a period of 60 min. RESULTS Intrathecal administration of zaprinast produced a dose-dependent suppression of flinches in both phases.
Zaprinast had no evident effects on baseline MAP or HR. CONCLUSIONS Zaprinast, a phosphodiesterase inhibitor, is active against the nociceptive state evoked by formalin stimulus without affecting resting MAP or HR. Accordingly, spinal zaprinast may be useful in the management of tissue-injury induced pain. |
Key Words:
antinociception; cyclic guanosine monophosphate; formalin test; hemodynamics; spinal cord; zaprinast |
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