title: Acetazolamide attenuates chemical-stimulated but not thermal-stimulated acute pain in mice.
abstract: OBJECTIVE
  Acetazolamide (AZA), a carbonic anhydrase (CA) inhibitor, has been found to alleviate inflammatory and neuropathic pain in rats. In the present study, we investigated the effects of AZA on thermal- and chemical-stimulated acute pain in mice and the possible mechanisms underlying the effects.
  
  
  METHODS
  Five acute pain models based on thermal and chemical stimuli were established to investigate the effects of AZA on different types of nociception in mice. The antinociceptive effects of methazolamide (another CA inhibitor) and diazepam (a positive allosteric modulator of GABAA receptor) were also examined. The drugs were administered either intraperitoneally (ip) or intrathecally.
  
  
  RESULTS
  AZA (50-200 mg/kg, ip) did not produce analgesia in two thermal-stimulated acute pain models, ie, mouse tail-flick and hot-plate tests. In contrast, AZA (50-200 mg/kg, ip) dose-dependently reduced paw licking time in both capsaicin and formalin tests in mice. A similar result was observed in a mouse acetic acid-induced writhing test. However, AZA (10 nmol/mouse, intrathecally) did not produce significant analgesia in the 3 chemical-stimulated acute pain models. In addition, methazolamide (50-200 mg/kg, ip) and diazepam (0.25-1.0 mg/kg, ip) did not produce significant analgesia in either thermal- or chemical-stimulated acute pain.
  
  
  CONCLUSIONS
  AZA produces analgesia in chemical-stimulated, but not thermal-stimulated acute pain in mice. The attenuation of chemical-stimulated acute pain by AZA may not be due to enhancement of GABAA receptor-mediated inhibition via inhibiting CA activity but rather a peripheral ion channel-related mechanism.
authors: 1] Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China [2] Now at Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors: Ya-jie
authors: YJ
authors: Sun
authors: Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors: Ying
authors: Y
authors: Chen
authors: Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors: Chong
authors: C
authors: Pang
authors: Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors: Ning
authors: N
authors: Wu
authors: Department of New Drug Evaluation, Beijing Institute of Pharmacology and Toxicology, Beijing 100850, China.
authors: Jin
authors: J
authors: Li
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology / Q000627:therapeutic use*; D059787:Acute Pain / Q000139:chemically induced* / Q000209:etiology / Q000517:prevention & control*; D000818:Animals; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D008297:Male; D051379:Mice; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D010147:Pain Measurement / Q000379:methods*; D013268:Stimulation, Chemical
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D000086:Acetazolamide