Today on POD 6, I did nociceptive testing (Mechanical allodynia followed by thermal hyperalgesia) in my experimental rat which had undergone a hind-paw incision (model of postoperative pain). When I measured mechanical allodynia using von-Frey filaments via Up-Down method (Chaplan et al., 1994), it was around 6.7 g then after a gap of 20 minutes, I measured thermal hyperalgesia using Hargreaves apparatus in the same rat.
Later, my supervisor tried to re-confirm/validate my results so, after 30 minutes of the first phase of the nociceptive testing which was done by me, he himself repeated testing for mechanical allodynia. Surprisingly, he got the different readings (~2 g) from that of mine and rat was showing a brisk flick after administration of the filaments to the medial site of incision.
I would be highly thankful to the forum members if they could torch some light on the enigma of validation/re-confirmation of the nociceptive assays’ results in this situation.
Thanks and regards,
AIIMS, New Delhi