Formalin

 The formalin test, which evaluates nociception caused by injection of dilute formalin solution into the hind paw, has been widely used and is considered one of the standard animal models of nociception. Injection of formalin into the mouse/rats hind paw produces nociceptive behaviors: an early transient phase (first phase; 5 min after injection) and a late persistent phase (second phase; 10 - 40 min after injection). Since formalin evokes a continuous nociceptive response generated by injured tissue, the activation of various endogenous pain regulatory substances has been proposed. Thus, the formalin test is considered to be of greater relevance for clinical situations than tests with more physic stimulus such as the tail-flick test.

Formalin model is suitable for a wide a verity of analgesics, including opioids, NSAIDs, any possessing antinociceptive effect receptor agonists/antagonists and ion channel modulators, either potent, or weak agents.

We have successfully established and validated rodent Formalin Test in our lab. It is available for compounds of potential analgesic drugs screen.