Valeriani Massimiliano, Tonali Pietro, De Armas Liala, Mariani Simona, Vigevano Federico, Le Pera Domenica
Division of Neurology, Ospedale Pediatrico Bambino Gesù, IRCCS, Piazza Sant'Onofrio 4, 00165 Rome, Italy.
Neurosci Res. 2008 Feb;60(2):170-5. doi: 10.1016/j.neures.2007.10.008. Epub 2007 Oct 30.
Our study aimed at investigating the nociceptive contribution to the somatosensory evoked potentials after electrical intramuscular stimulation (mSEPs) at painful intensity. Scalp mSEPs were recorded in 10 healthy subjects after electrical stimulation of the left brachioradialis muscle at three intensities: non-painful (I2), slightly painful (I4) and moderately painful (I6). For each intensity, mSEPs were recorded in a neutral condition (NC) in which subjects did not have any task, and in an attention condition (AC) in which subjects were asked to count the number of stimuli. In both NC and AC, the N120 and P220 amplitudes were significantly higher at I6 than at I2. While the N120 amplitude did not vary between NC and AC, the P220 amplitude was significantly higher in AC than in NC at all stimulus intensities. Our results suggest that nociceptive inputs contribute to the N120 amplitude increase at painful stimulus intensity, while the P220 amplitude is more sensitive to changes of subjects' attention level. Therefore, the N120 amplitude increase to moderately painful stimuli, as compared to non-painful stimuli, may represent a marker of the activation of the muscular thin myelinated afferents.
我们的研究旨在探究在疼痛强度下进行肌肉内电刺激后（运动体感诱发电位，mSEPs），伤害性感受对体感诱发电位的影响。对10名健康受试者的左侧肱桡肌进行三种强度的电刺激后，记录头皮mSEPs：非疼痛强度（I2）、轻微疼痛强度（I4）和中度疼痛强度（I6）。对于每种强度，在中性条件（NC）下记录mSEPs，即受试者无需执行任何任务；以及在注意力条件（AC）下记录，即要求受试者数刺激次数。在NC和AC两种条件下，I6时的N120和P220波幅均显著高于I2时。虽然N120波幅在NC和AC之间没有变化，但在所有刺激强度下，AC时的P220波幅均显著高于NC时。我们的结果表明，伤害性感受输入导致疼痛刺激强度下N120波幅增加，而P220波幅对受试者注意力水平的变化更敏感。因此，与非疼痛刺激相比，中度疼痛刺激导致的N120波幅增加可能代表肌肉细有髓传入纤维激活的一个标志。
