Experimental skin pain and muscle pain induce distinct changes in human trigeminal motoneuronal excitability

摘要: Seeking information on the physiological properties of trigeminal motoneuronal pool we investigated changes in excitability motor system induced by two types experimental pain (muscle and skin). In one session, studied effect muscle hypertonic saline infusion into masseter recovery cycle heteronymous H-reflex temporalis homonymous silent period (SP) muscle, both elicited stimulation masseteric nerve ten-healthy subjects. another laser stimuli applied to perioral region, at conditioning intervals from 20 160 ms, SP nine healthy Whereas laser-induced skin significantly inhibited facilitated (P 0.05). The timing suppression masseter-SP enhancement indicates that facial nociceptors inhibit motoneurones via multysynaptic reflex pathways. Hypertonic saline, a stimulus predominantly activates group III IV afferents, left variables reflecting motoneuron unchanged. Due differences between models, cannot conclude such inhibitory pathway does not exist motoneurones.