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Melior Discovery pain/neuropathic

Hargreaves Hyperalgesia Assay
Hyperalgesia is a condition of enhanced sensitivity to painful stimuli.  The Hargreaves test is utilized to assess changes in threshold latency to a small source of radient heat on the hind paw.  Intraplantar carrageenan increases hyperalgesia in the rat hindpaw and is commonly used in assays of hyperalgesia.  This study examines the effects of morphine in a rat model of thermal hyperalgesia.

Figure 1: Paw Withdrawal Latency  Three Hours Post Carrageenan Injections

                       Hargreaves Hyperalgesia Assay with Morphine

Paw Withdrawal Latency.  Carrageenan reduced paw withdrawal latency after three hours in the intraplantar-injected left hindpaw compared to the non-injected right hindpaw.  This effect was not significant.  Data are ± SEM; ****p<0.0001 compared to baseline,***p<0.001 compared to Carrageenan.

 

Figure 2: Morphine's Effect on Paw Withdrawal

                                   Hargreaves Hyperalgesia Assay with Carrageenan and Morphine

Morphine's Effect on Paw Withdraw after Carrageenan Challenge.  Morphine (5mpk) significantly increased paw withdrawal latency compared to vehicle control animals. Data are ± SEM; ****p<0.0001 compared to Carrageenan.

 

If you are interested in learning more about the Hargreaves Hyperalgesia Assay, please contact models@meliordiscovery.com to start the conversation today.