RESUMEN
Motor nerve conduction velocities (MNCVs) of ventral peripheral tail nerves of unanaesthetized streptozotocin diabetic rats were examined in comparison to age matched normal rats under normal and ischemic conditions. A miniature blood pressure cuff was applied to the base of the tail and was adjusted to provide complete vascular occlusion for 30 min. MNCVs were recorded during ischemia and in the post-ischemic period. MNCVs were markedly reduced during ischemia in normal rats but were unchanged in diabetic rats. Conversely, the sensation of heat induced pain was retained to an equal extent in normal and diabetic rats during ischemia states. The abnormal resistance to ischemia of MNCV of peripheral nerves is an early and sensitive index of nerve dysfunction and precedes slowing of MNCV in diabetic rats. The results suggest that initial peripheral nerve abnormalities in diabetic rats may be related to biochemical changes rather than axonopathy and may have heuristic significant for clinical diabetic neuropathy.
Asunto(s)
Envejecimiento , Animales , Glucemia/metabolismo , Presión Sanguínea , Diabetes Mellitus Experimental/fisiopatología , Femenino , Isquemia/fisiopatología , Neuronas Motoras/fisiología , Conducción Nerviosa , Neuronas Aferentes/fisiología , Nociceptores/fisiología , Nervios Periféricos/fisiología , RatasRESUMEN
A bilaterally synchronous 3/sec spike and wave pattern in the EEG can be obtained during stimulation of the nucleus medialis dorsalis (nMD) and nucleus paracentralis (nPC) of the thalamus, in lightly anaesthetized juvenile monkeys. The spike and wave EEG patterns have a frequency of 2 1/2 to 3Hz and occur during low frequency stimulation, without continuing into the post-stimulatory phase. Stimulation of the mesencephalic reticular formation (MRF) at higher voltages inhibits the thalamic-induced spike and wave response. This finding has heuristic significance, as activating stimuli arrest the wave and spike EEG pattern of human absence (petit mal epilepsy) seizures. The study also demonstrates the morphological similarity of the 3/sec spike and wave thalamic induced response in experimental and clinical absence states as well as similarities in their alterations with different levels of activation.