Autonomic dysfunction in experimental autoimmune neuritis: Heart rate

Autonomic nervous system (ANS) dysfunction occurs in more than half of Guil lain-Barre syndrome (GBS) patients and is an important cause of death in th e disease. In this study we examined heart rate (HR) changes in an animal m odel of GBS, experimental autoimmune neuritis (EAN), induced by immunizatio n with myelin extracted from bovine spinal roots. The animals developed pro gressive motor weakness accompanied by significant weight loss and hypother mia. HR was measured in 33 EAN rats at rest (rHR) and followings stressful stimulation (sHR). Average pre-immunization rHR was 341 +/- 28 beats per mi nute (b.p.m.) and sHR was 486 +/- 21 bpm. Although the mean rHR in rats wit h EAN was not significantly different compared to that at baseline, there w as a significant increase of variation of rHR with six rats demonstrating b radycardia (<280 b.p.m.) and 10 tachycardia (>400 b.p.m.) (P<0.01, F-test). sHR in EAN rats was significantly lower (P<0.01), suggesting sympathetic s ystem impairment. These findings may serve as a basis for testing treatment s of ANS dysfunction in EAN. (C) 2001 Published by Elsevier Science B.V.