Yerdelen Deniz, Uysal Hilmi, Koç Filiz, Sarica Yakup
Department of Neurology, Cukurova University Faculty of Medicine, Adana, Turkey.
Clin Neurophysiol. 2007 Jan;118(1):105-10. doi: 10.1016/j.clinph.2006.09.017. Epub 2006 Nov 13.
Hyperventilation and ischaemia increase axonal excitability by changing Na+ conductance in healthy subjects. However, the changes in excitability during and after ischaemia in diabetic patients are less than in healthy controls. This is known as ischaemic resistance. In this study, we investigated the effects of hyperventilation for 20 min on strength-duration time constant (SDTC) of motor axons of the median nerve of diabetic patients with polyneuropathy to determine whether diabetics are less affected by hyperventilation, a form of resistance similar to the ischaemic resistance of diabetics.
The SDTC of 14 diabetic patients with polyneuropathy and 10 healthy volunteers were measured following stimulation of right median nerve at the wrist prior to and after hyperventilation for 20 min.
There was a significant increase in the SDTC in control subjects, but no significant change in the SDTC for patients with diabetic polyneuropathy. The score of the clinical response (paraesthesiae and carpopedal spasm) to hyperventilation of controls was also significantly greater in the controls than the patients.
Hyperventilation for 20 min has little influence on SDTC in patients with diabetic polyneuropathy.
The 'resistance' of diabetic nerve is not confined to ischaemia but involves other manoeuvres that can alter axonal excitability.
在健康受试者中，过度通气和局部缺血会通过改变钠离子电导来增加轴突兴奋性。然而，糖尿病患者在局部缺血期间及之后的兴奋性变化小于健康对照组。这被称为缺血抵抗。在本研究中，我们调查了20分钟过度通气对患有多发性神经病的糖尿病患者正中神经运动轴突强度-时间常数（SDTC）的影响，以确定糖尿病患者是否受过度通气的影响较小，这是一种类似于糖尿病患者缺血抵抗的抵抗形式。
在20分钟过度通气之前和之后，对14名患有多发性神经病的糖尿病患者和10名健康志愿者的右腕正中神经进行刺激，测量其SDTC。
对照组的SDTC显著增加，但糖尿病多发性神经病患者的SDTC无显著变化。对照组对过度通气的临床反应（感觉异常和手足痉挛）评分也显著高于患者。
20分钟的过度通气对糖尿病多发性神经病患者的SDTC影响很小。
糖尿病神经的“抵抗”不仅限于缺血，还涉及其他可改变轴突兴奋性的操作。
