The automated measurement of hindlimb flexor reflex of the rat as a substitute for the tail-flick assay.
A new method for the study of stimulation-produced analgesia is introduced. The hindlimb flexor EMG, in response to noxious electrical stimulation of the paw, is used as an indirect index of analgesia induced by electrical stimulation at different brain sites. In the lightly anesthetized rat (pentobarbital 10-20 mg/kg/h) such responses are quite stable and easily evoked at intertrial intervals as short as 10 s without habituation. The high repetition rate allows a rapid determination of the threshold current intensities or the brain stimuli required to suppress the hindlimb withdrawal. The test is objective, avoids skin damage and sensitization and can be performed semi-automatically when implemented with a small PC.
Duysens
J
J
Laboratory of Medical Physics ad Biophysics, University of Nijmegen, The Netherlands.
Gybels
J
J
D000818:Animals; D001921:Brain / Q000502:physiology; D004558:Electric Stimulation; D004576:Electromyography; D006614:Hindlimb; D008838:Microcomputers; D010147:Pain Measurement / Q000379:methods*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000502:physiology*