Ablation of rat TRPV1-expressing Adelta/C-fibers with resiniferatoxin: analysis of withdrawal behaviors, recovery of function and molecular correlates

Table 1 Latency to observable movement following short-pulse (100 ms), high intensity stimulation with infrared diode laser (6.08 W/mm2)

	Standing on 2 or 3 paws	Standing on 4 paws	Total
Total number of trials	8	8	16
Shortest latency to fLEM	56 ms	74 ms	56 ms
†Fastest conduction velocity	3.0 m/s	2.3 m/s	3.0 m/s
Mean latency to fLEM (± SEM)	159.5 ± 36.7 ms	250.0 ± 28.9 ms	204.8 ± 25.4
†Mean conduction velocity	1.1 m/s	0.7 m/s	0.8 m/s
Shortest latency to withdrawal of stimulated limb	74 ms	128 ms	74 ms
Mean latency to withdrawal of stimulated limb (± SEM)	213.0 ± 34.1	271.0 ± 27.7	242.0 ± 22.5

†Conduction velocities are likely a gross underestimation of the actual conduction velocities. They do not account for central delay (~80 ms in the rat) [32], motoneuron conduction velocity (33-85 m/s) [33] or the time required for muscle contraction/relaxation (34-116 ms) [33]. Nonetheless, we were able to demonstrate that it is possible to detect nocifensive behaviors that are temporally consistent with being mediated by Aδ-fibers. The posture of the animal before stimulation appears to greatly influence our ability to detect movements with short or longer latencies.

ISSN: 1744-8069