Differences between somatosensory-evoked potentials recorded from the ventral posterolateral thalamic nucleus, primary somatosensory cortex and vertex in the rat.
Somatosensory-evoked potential (SEP) components recorded over the primary somatosensory cortex (SI) and vertex in the rat within the 10-30 ms latency range were characterised with respect to the anatomy and function of the primary somatosensory pathway. To this aim, these components were compared to SEP components in the similar latency range recorded from the ventral posterolateral thalamic (VPL) nucleus, a nucleus known to be part of the subcortical structure of the primary somatosensory pathway and were described with respect to their stimulus-response characteristics and their response to the mu-opioid agonist fentanyl. The VPL positive (P)11-negative (N)18-P22 and SI P13-N18-P22 differed with respect to peak occurrence (P11 versus P13, respectively) and waveform morphology, but did not differ with respect to stimulus-response characteristics and their response to fentanyl. When compared to the vertex P15-N19-P26, the VPL P11-N18-P22 and SI P13-N18-P22 complex follow a relatively fast acquisition in stimulus intensity-response and were affected significantly less to increasing stimulus frequencies and to fentanyl. These results demonstrated that when compared to the VPL-SEP and SI-SEP, the Vx-SEP was modulated differently by the experimental conditions. It is suggested that this may be related to involvement of neural structures within different functional somatosensory pathways.
Stienen
Peter J
PJ
Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, The Netherlands. P.Stienen@vet.uu.nl
de Groot
Harry N M
HN
Venker-van Haagen
Anjop J
AJ
van den Brom
Walter E
WE
Hellebrekers
Ludo J
LJ
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects* / Q000502:physiology; D005283:Fentanyl / Q000494:pharmacology*; D020647:Lateral Thalamic Nuclei / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D013003:Somatosensory Cortex / Q000187:drug effects* / Q000502:physiology
D000701:Analgesics, Opioid; D005283:Fentanyl